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1
Qi, Yue. "(Invited) Modeling the Charge Transfer Reactions at Li/SEI/Electrolyte Interfaces in Lithium-Ion Batteries". ECS Meeting Abstracts MA2023-01, n. 45 (28 agosto 2023): 2452. http://dx.doi.org/10.1149/ma2023-01452452mtgabs.
Testo completoAbstract (sommario):
Two kinds of charge transfer reactions are critical for the performance and life of lithium battery: the desired ion transfer reaction occurring during each charge/discharge cycle, , and the undesired electron transfer reactions leading to the parasitic chemical decomposition of the electrolyte and solid electrolyte interphase (SEI) formation/growth. The heterogeneous multi-component nature of SEI dominates its ionic and electronic transport properties and controls these two charge transfer reactions. Density Functional Theory (DFT)-informed multiscale modeling has been providing valuable insights under the scarcity of quantitative experiments. For example, the LiF/Li2CO3 interface was demonstrated to increase the ionic conductivity of mixed SEI nanocomposite by forming an ionic space charge region near the interface and promoting more Li-ion interstitials in Li2CO3, although LiF itself has low Li-ion conducting carriers and conductivity. To form a LiF-rich SEI layer, the electrolyte compositions need to be designed. Since the SEI formation occurs on the charged surface, the electric double layer (EDL) structure near the charged surfaces needs to be incorporated into the modeling. Here interactive classical molecular dynamics (MD), DFT, and data statistical analysis were combined to illustrate the effect of EDL on SEI formation in two essential electrolytes, the carbonate-based electrolyte for Li-ion batteries and the ether-based electrolyte for batteries with Li-metal anodes. It was found the effectiveness of adding fluoroethylene carbonate (FEC) to form the beneficial F-containing SEI component (e.g., LiF) varies with the electrolyte and temperature, because of the interplay of ion-solvent interactions with the surface charge. These integrated modeling provided quantitative guidance for electrolyte/SEI/Li-metal interface design.
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Morasch, Robert, Hubert A. Gasteiger e Bharatkumar Suthar. "Li-Ion Battery Material Impedance Analysis II: Graphite and Solid Electrolyte Interphase Kinetics". Journal of The Electrochemical Society 171, n. 5 (1 maggio 2024): 050548. http://dx.doi.org/10.1149/1945-7111/ad48c0.
Testo completoAbstract (sommario):
Li-ion battery graphite electrodes form a solid-electrolyte-interphase (SEI) which is vital in protecting the stability and efficiency of the cell. The SEI properties have been studied extensively in the context of formation and additives, however studying its kinetic features after formation have been neglected. In this study we show the dynamic resistive behavior of the SEI after formation. Via electrochemical impedance spectroscopy measurements on Cu-foil after SEI formation we show how the SEI shows a potential-dependent resistance which can be explained by a change in charge carriers (Li+) in the SEI. Additional measurements on graphite exhibit a similar behavior and allow us to separate the charge transfer kinetics from the SEI resistance, showing that the SEI resistance is the dominating resistance in the graphite kinetics. Measurements on pre-formed electrodes also show how the SEI resistance changes when in contact with electrolyte of different LiPF6 salt concentrations, with the resistance decreasing for increasing salt concentrations. Ultimately, we show that the SEI resistance affects Li-plating by acting as an offset to the plating reaction but does not affect the nucleation overpotential itself.
3
Lee, Sangyup, e Soon-Ki Jeong. "Investigation of the electrochemical properties of a propylene carbonate-derived SEI in an ethylene carbonate-based solution". BIO Web of Conferences 62 (2023): 04002. http://dx.doi.org/10.1051/bioconf/20236204002.
Testo completoAbstract (sommario):
Herein, we aim to explore and analyze the influence of electrolytes on the creation of a solid electrolyte interface (SEI) within ethylene carbonate (EC) and propylene carbonate (PC)-based electrolyte solutions. Our investigation reveals that despite variations in the charge consumption during SEI formation, a comparable SEI is generated in a high-concentration PC-based electrolyte as observed in an EC-based electrolyte. However, it is noteworthy that the SEI originating from the PC-based electrolyte exhibits a significantly higher resistance to lithium ion transport when compared to the SEI formed from the EC-based electrolyte. Moreover, an increase in the charge transfer resistance at the graphite/electrolyte interface is observed in the PC-based electrolyte. These significant findings strongly imply that the choice of electrolyte solvent is a critical factor that must be taken into consideration in order to achieve the formation of an effective SEI.
4
Jeong, Soon Ki. "Effects of Lithium Salt on Interfacial Reactions between SiC and EC-Based Solutions in Lithium Secondary Batteries". Applied Mechanics and Materials 873 (novembre 2017): 112–16. http://dx.doi.org/10.4028/www.scientific.net/amm.873.112.
Testo completoAbstract (sommario):
Electrochemical reactions occurring at a SiC electrode were investigated to gain insight into the effects of lithium salts, such as LiPF6, LiClO4, LiCF3SO3, and LiBF4, on the interfacial resistance. Lithium salts were found to exert little effect on the magnitude of the resistance of the solid-electrolyte interphase (SEI). In contrast, the charge-transfer reactions observed in the LiCF3SO3-containing solution exhibited the smallest resistance. Charge-discharge analysis revealed that the nature of the SEI was significantly different from that formed in ethylene carbonate-based solutions containing different lithium salts. The SiC electrode exhibited large discharge capacity and low coulombic efficiency in the LiCF3SO3-containing solution. This might be closely related to the smallest charge-transfer resistance.
5
Tsujimoto, Shota, Changhee Lee, Yuto Miyahara, Kohei Miyazaki e Takeshi Abe. "Effect of Electrolyte on Sodium-Ion Storage Behavior into Non-Graphitizable Carbon Negative Electrode". ECS Meeting Abstracts MA2023-02, n. 4 (22 dicembre 2023): 806. http://dx.doi.org/10.1149/ma2023-024806mtgabs.
Testo completoAbstract (sommario):
Introduction Sodium-ion batteries (SIBs) are expected to be an alternative power source to lithium-ion batteries (LIBs) because their abundant resources reduce the cost of SIBs. As the negative electrode of SIBs, non-graphitizable carbon recieves a lot of attention because it can store ions not only in the graphene interlayer but also in its internal pores.[1] By controlling the pores, it is possible to achieve larger reversible capacity of more than 400 mAh g−1.[2] While many researchers have studied non-graphitizable carbon from the viewpoint of thermodynamics, there are a few reports that pay attention to kinetic viewpoint. The kinetic viewpoint is a very important factor because it affects the rate performance of the battery. We have focused on the interfacial reactions of non-graphitizable carbon electrodes and found that the charge-transfer resistance and the activation energy of the charge-transfer reaction in SIBs were larger than those in LIBs.[3] This result and the Lewis acidity indicated that the desolvation process was not identified as the rate determining step in the charge-transfer reaction. One of the significant factors responsible for the increased resistance is the effect of the solid electrolyte interphase (SEI). Objective In this work, we used six types of electrolytes and formed SEI on the surface of non-graphitizable carbon. The interfacial reaction of non-graphitizable carbon with SEI derived from these electrolytes was investigated. In this paper, we report about the effects of SEI on the interfacial reaction between electrolyte and non-graphitizable carbon electrode. Experimental Non-graphitizable carbon heat-treated at 2273 K (HC-2000) was used as the negative electrode material. A three-electrode cell was used for electrochemical measurements. HC-2000 composite electrode, natural graphite composite electrode, and sodium metal were used as the working electrode, counter electrode, and reference electrode, respectively. The electrolytes were prepared using sodium bis(trifluoromethanesulfonyl) amide (NaTFSA), sodium bis(fluorosulfonyl) amide (NaFSA), and NaPF6 as sodium salts and ethylene carbonate (EC) + diethyl carbonate (DEC) (1:1 by volume) and fluoroethylene carbonate (FEC) as solvents. Cyclic voltammetry (CV) was performed to form SEI on HC-2000. The scan rate and range were 0.1 mV s−1 and 0–2.5 V, respectively. After CV, electrochemical impedance spectroscopy (EIS) was performed with an electrode potential of 0.2 V and an AC amplitude of 10 mV in the frequency range of 100 kHz–10 mHz. In addition, X-ray photoelectron spectroscopy (XPS) was used to analyze the electrode after CV measurements with respect to SEI. Results and discussion Figure 1 shows the Nyquist plots obtained from the EIS analyses. The semicircles in the low frequency region were attributed to the charge-transfer resistances. Among EC+DEC solvents, the system of NaFSA had the largest charge-transfer resistance. For NaTFSA and NaPF6, the charge-transfer resistances increased in the FEC solvent, while no significant differences in the charge-transfer resistance were observed for the NaFSA system in the EC+DEC and FEC solvents. The SEI components of the HC-2000 composite electrode in each electrolyte were determined by XPS analysis after CV measurements. In NaFSA/EC+DEC system, the amount of NaF was remarkably large, while the amount of NaF was relatively small in NaTFSA/EC+DEC and NaPF6/EC+DEC systems. On the other hand, in FEC solvents, the amount of NaF increased in NaTFSA and NaPF6 systems. The systems with higher NaF contents had the larger charge-transfer resistances. This result indicates that NaF was involved in the charge-transfer resistance. Finally, EIS analyses were performed at different temperatures. The activation energies were calculated using Arrhenius plots and the Arrhenius equation. The values of the activation energies were in the range of 60–70 kJ mol−1. There was a slight variation in the values, but they were within the error range and were not significantly different for all systems. These results showed that NaF affects the frequency factor rather than the activation energy. Conclusion The effects of SEI on the interfacial reaction between electrolyte and non-graphitizable carbon were investigated. The systems with the large charge-transfer resistance had a large amount of NaF. NaF did not affect the activation energy of charge-transfer resistance but did affect the frequency factor. References [1] D. A. Stevens and J. R. Dahn, J. Electrochem. Soc., 147(4), 1271-1273 (2000). [2] A. Kamiyama, K. Kubota, D. Igarashi, Y. Youn, Y. Tateyama, H. Ando, K. Gotoh, and S. Komaba, Angew. Chem. Int. Ed., 60, 5114-5120 (2021). [3] S. Tsujimoto, Y. Kondo, Y. Yokoyama, Y. Miyahara, K. Miyazaki, and T. Abe, J. Electrochem. Soc., 168, 070508 (2021). Figure 1
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Zhou, Xuan, Ping Li, Zhihao Tang, Jialu Liu, Shaowei Zhang, Yingke Zhou e Xiaohui Tian. "FEC Additive for Improved SEI Film and Electrochemical Performance of the Lithium Primary Battery". Energies 14, n. 22 (9 novembre 2021): 7467. http://dx.doi.org/10.3390/en14227467.
Testo completoAbstract (sommario):
The solid electrolyte interphase (SEI) film plays a significant role in the capacity and storage performance of lithium primary batteries. The electrolyte additives are essential in controlling the morphology, composition and structure of the SEI film. Herein, fluoroethylene carbonate (FEC) is chosen as the additive, its effects on the lithium primary battery performance are investigated, and the relevant formation mechanism of SEI film is analyzed. By comparing the electrochemical performance of the Li/AlF3 primary batteries and the microstructure of the Li anode surface under different conditions, the evolution model of the SEI film is established. The FEC additive can decrease the electrolyte decomposition and protect the lithium metal anode effectively. When an optimal 5% FEC is added, the discharge specific capacity of the Li/AlF3 primary battery is 212.8 mAh g−1, and the discharge specific capacities are respectively 205.7 and 122.3 mAh g−1 after storage for 7 days at room temperature and 55 °C. Compared to primary electrolytes, the charge transfer resistance of the Li/AlF3 batteries with FEC additive decreases, indicating that FEC is a promising electrolyte additive to effectively improve the SEI film, increase discharge-specific capacities and promote charge transfer of the lithium primary batteries.
7
Li, Galina, Aleksander Rumyantsev, Ekaterina Astrova e Maxim Maximov. "Growth of the Cycle Life and Rate Capability of LIB Silicon Anodes Based on Macroporous Membranes". Membranes 12, n. 11 (25 ottobre 2022): 1037. http://dx.doi.org/10.3390/membranes12111037.
Testo completoAbstract (sommario):
This work investigated the possibility of increasing the cycle life and rate capability of silicon anodes, made of macroporous membranes, by adding fluoroethylene carbonate (FEC) to the complex commercial electrolyte. It was found that FEC leads to a decrease in the degradation rate; for a sample without FEC addition, the discharge capacity at the level of Qdch = 1000 mAh/g remained unchanged for 220 cycles and the same sample with 3% FEC added to the electrolyte remained unchanged for over 600 cycles. FEC also improves the power characteristics of the anodes by 5–18%. Studies of impedance hodographs showed that in both electrolytes (with 0% and 3% FEC, respectively) the charge transfer resistance grows with an increasing number of cycles, while Solid Electrolyte Interphase (SEI) parameters, such as its resistance and capacitance, show little change. However, the addition of FEC more than halves the overall system impedance and reduces the resistance of the liquid electrolyte and all current carrying parts as well as the SEI film and charge transfer resistances.
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Housel, Lisa M., Alyson Abraham, Genesis D. Renderos, Kenneth J. Takeuchi, Esther S. Takeuchi e Amy C. Marschilok. "Surface Electrolyte Interphase Control on Magnetite, Fe3O4, Electrodes: Impact on Electrochemistry". MRS Advances 3, n. 11 (2018): 581–86. http://dx.doi.org/10.1557/adv.2018.294.
Testo completoAbstract (sommario):
ABSTRACTIn battery systems, a solid electrolyte interphase (SEI) is formed through electrolyte reaction on an electrode surface. The formation of SEI can have both positive and negative effects on electrochemistry. The initial formation of the layer protects the electrode from further reactivity, which can improve both shelf and cycle life. However, if the layer continues to form, it can impede charge transfer, which increases cell resistance and limits cycle life. The role of SEI is particularly important when studying conversion electrodes, since phase transformations which unveil new electroactive surfaces during reduction/oxidation can facilitate electrolyte decomposition. This manuscript highlights recent developments in the understanding and control of SEI formation for magnetite (Fe3O4) conversion electrodes through electrolyte and electrode modification.
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Zhuang, Qinqin, Weihuang Yang, Wei Lin, Linxi Dong e Changjie Zhou. "Gas Sensing of Monolayer GeSe: A First-Principles Study". Nano 14, n. 10 (ottobre 2019): 1950131. http://dx.doi.org/10.1142/s1793292019501315.
Testo completoAbstract (sommario):
The adsorption of various gas molecules (H2, H2O, CO, NH3, NO and NO[Formula: see text] on monolayer GeSe were investigated by first-principles calculations. The most stable configurations, the adsorption energies, and the amounts of charge transfer were determined. Owing to the appropriate adsorption energies and the non-negligible charge transfers, monolayer GeSe could be a promising candidate as a sensor for NH3, CO, NO and NO2. According to the band structures of the H2O, CO, NH3, NO and NO2 adsorbed systems, the reductions of the bandgaps are caused by the orbital hybridizations between the gas molecules and the underlying GeSe. The partial densities of states reveal the degrees of these orbital hybridizations. The mechanisms of charge transfer are discussed in the light of both traditional and orbital mixing charge transfer theories. The charge transfer of the paramagnetic molecules NO and NO2 could be governed by both charge transfer mechanisms, while for the other gas molecules H2, H2O, CO and NH3, it was most likely determined by the mixing of the HOMO or LUMO with the GeSe orbitals.
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Potapenko, Anna V., Oleksandr V. Potapenko, Oleksandr V. Krushevskyi e Miaomiao Zhou. "EIS Analysis of Sulfur Cathodes with Water-Soluble Binder NV-1A for Lithium-Sulfur Batteries". ECS Transactions 105, n. 1 (30 novembre 2021): 225–29. http://dx.doi.org/10.1149/10501.0225ecst.
Testo completoAbstract (sommario):
The paper discusses the electrochemical behavior of a Li-S battery with a new water-soluble binder NV-1A. It is shown that the main contribution is made by the interface, which is formed on the lithium counter electrode. It is noteworthy that the nonlinear growth of the resistance of SEI layer during the discharge process correlates with the change in the resistance of charge transfer through the interface.
11
Singh, Triesha, e Bryan D. McCloskey. "Correlating Solid-Electrolyte Interface Composition to Charge Transfer Resistance for Improved Low-Temperature Performance of Lithium-Ion Batteries". ECS Meeting Abstracts MA2023-02, n. 5 (22 dicembre 2023): 883. http://dx.doi.org/10.1149/ma2023-025883mtgabs.
Testo completoAbstract (sommario):
The adverse impact of low temperatures on Li-ion batteries (LIBs) is a well known challenge. Currently, at subfreezing temperatures, the efficiency of conventional LIBs greatly decreases compared to their room temperature performance, which of course severely limits the performance of applications using LIBs in the colder regions on the planet. From a fundamental perspective, the causes of such performance decreases are yet to be fully understood, but are believed to be related to the ability of ions to move through the various phases (as well as move across phase interfaces) that exist in the battery. Several studies have been conducted to improve the low-temperature performance of LIBs, most of them focusing on using solvents with lower viscosity and higher dielectric constant to promote transport through the electrolyte at the lower temperatures so as to achieve lower bulk resistance (Rbulk) of the cell. However, our Electrochemical Impedance Spectroscopy (EIS) studies at low temperatures have indicated that it is the charge transfer resistance (Rct) that grows exponentially as we go to sub-zero Celsius temperatures and is responsible for the increase in the total resistance of the cell. EIS on 3-electrode cells have shown that the anode side (Gr) is predominantly responsible for the poor cell performance, necessitating our focus on the charge transfer process in the Gr-electrolyte interface. We observe that the Rct is not only related to the Li-solvation shell but also to the composition of the Solid Electrolyte Interface (SEI). By modifying the electrolyte, such as by changing the salt concentration, adding additives, and changing the solvent, significant changes in the interface and hence in the RSEI and Rct of the cell have been observed. By combining EIS with various techniques like mass spectrometry, differential capacity analysis and SEM, we have been able to better understand the SEI composition and its impact on interfacial resistances. We specifically focus on the influence of SEI composition on the charge-transfer resistance of the cell, correlating the effect of amounts of LiF and carbonates in the SEI with the interfacial performance of the cell. Through these relations, we aim to facilitate the development of electrolytes by having a better understanding of the solvation shells and the SEI composition for low temperature performance.
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Li, Yunsong, e Yue Qi. "Energy landscape of the charge transfer reaction at the complex Li/SEI/electrolyte interface". Energy & Environmental Science 12, n. 4 (2019): 1286–95. http://dx.doi.org/10.1039/c8ee03586e.
Testo completo
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Kallel, Ahmed Yahia, Viktor Petrychenko e Olfa Kanoun. "State-of-Health of Li-Ion Battery Estimation Based on the Efficiency of the Charge Transfer Extracted from Impedance Spectra". Applied Sciences 12, n. 2 (16 gennaio 2022): 885. http://dx.doi.org/10.3390/app12020885.
Testo completoAbstract (sommario):
Several studies show that impedance spectroscopy is a suitable method for online battery diagnosis and State-of-Health (SoH) estimation. However, the most common method is to model the acquired impedance spectrum with equivalent circuits and focus on the most sensitive parameters, namely the charge-transfer resistance. This paper introduces first a detailed model of a battery cell, which is then simplified and adapted to the observable spectrum behavior. Based on the physical meaning of the model parameters, we propose a novel approach for SoH assessment combining parameters of the impedance spectrum by building the ratio of the solid electrolyte interphase (SEI) resistance to the total resistance of SEI and the charge transfer. This ratio characterizes the charge-transfer efficiency at the electrodes’ surfaces and should decrease systematically with SoH. Four different cells of the same type were cycled 400 times for the method validation, and impedance spectroscopy was performed at every 50th cycle. The results show a systematic correlation between the proposed ratio and the number of cycles on individual cell parameters, which build the basis of a novel online method of SoH assessment.
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Gu, Xin, Li Zhang, Wenchao Zhang, Sailin Liu, Sheng Wen, Xinning Mao, Pengcheng Dai et al. "A CoSe–C@C core–shell structure with stable potassium storage performance realized by an effective solid electrolyte interphase layer". Journal of Materials Chemistry A 9, n. 18 (2021): 11397–404. http://dx.doi.org/10.1039/d1ta01107c.
Testo completoAbstract (sommario):
A CoSe–C@C core–shell structure is designed as a novel potential anode for PIBs. The introduction of KFSI salt is found to contribute to the formation of an inorganic-compound-rich SEI layer, benefiting the K ion diffusion and charge transfer dynamics.
15
Park, Kyoung Soo, Soon Ki Jeong e Yang Soo Kim. "Electrochemical Properties of NbO as a Negative Electrode Material for Lithium Secondary Batteries". Applied Mechanics and Materials 835 (maggio 2016): 126–30. http://dx.doi.org/10.4028/www.scientific.net/amm.835.126.
Testo completoAbstract (sommario):
The electrochemical properties of niobium monoxide, NbO, were investigated as a negative electrode material for lithium-ion batteries. Lithium ions were inserted into and extracted from NbO material at potentials < 1.0 V versus Li/Li+, involving formation of a solid electrolyte interface (SEI) on the NbO surface in the first cycle. Its reversible capacity is ~67 mAh g–1 with the capacity retention of ~109% after 50 cycles. The magnitude of charge transfer resistance was greatly decreased by ball-milling the pristine NbO, whereas the ball-milling had no effect on the SEI resistance.
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Saito, Morihiro, Yoshiyuki Nakano, Mikihiro Takagi, Takuma Maekawa, Akimasa Tasaka, Minoru Inaba, Hitoshi Takebayashi e Yoshio Shodai. "Effect of Surface Fluorination on the Charge/Discharge Properties of High Potential Negative Electrode TiO2(B) for LIBs". Key Engineering Materials 582 (settembre 2013): 127–30. http://dx.doi.org/10.4028/www.scientific.net/kem.582.127.
Testo completoAbstract (sommario):
Surface fluorination of TiO2(B) powder was conducted by pure F2 gas at room temperature for 1 h and the effect on the charge/discharge properties was examined as a negative electrode of Li-ion batteries (LIBs). X-ray diffraction (XRD) pattern was not changed before and after the surface fluorination though the peak intensities became weaker than that of the pristine sample, indicating the etching of the surface of SF-TiO2(B) power. This was supported by scanning electron microscopy (SEM) observation. However, X-ray photoelectron spectroscopy (XPS) analysis clearly revealed that F atoms exist on the surface of TiO2(B) particles and probably were covalently bonded with Ti atoms near the surface. From the charge/discharge tests at a C/6 rate, the SF-TiO2(B) exhibited a higher 1st discharge (203 mAh g-1) than the pristine sample (181 mAh g-1) with a good cycleability. Impedance analysis revealed that both resistances of solid electrolyte interphase (SEI) film and charge transfer at the SEI /active material interface were reduced by surface fluorination, implying the improvement of SEI film and permeability of the electrolyte solution to the interphase. The rate capability was improved by the surface fluorination up to 1C rate, at which the SF-TiO2(B) exhibited a high discharge capacity of around 150 mAh g-1.
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Tsujimoto, Shota, Changhee Lee, Yuto Miyahara, Kohei Miyazaki e Takeshi Abe. "Effect of Solid Electrolyte Interphase on Sodium-Ion Insertion and Deinsertion in Non-Graphitizable Carbon". Journal of The Electrochemical Society 170, n. 9 (1 settembre 2023): 090526. http://dx.doi.org/10.1149/1945-7111/acf8fe.
Testo completoAbstract (sommario):
Non-graphitizable carbon allows reversible sodium-ion intercalation and hence enables stable and high-capacity sodium storage, making it a promising material for achieving long-term cycling stability in sodium-ion batteries (SIBs). This study investigated the interfacial reactions between various electrolytes and a non-graphitizable carbon electrode for their use in SIBs. The morphology and particle diameter of the non-graphitizable carbon, HC-2000, remained unchanged after heat treatment, indicating its stability. The X-ray diffraction pattern and Raman spectrum suggested a disordered structure of HC-2000 carbon. The interlayer spacing, Brunauer–Emmett–Teller specific surface area, and density were determined to be 0.37 nm, 5.8 m2 g−1, and 1.36 g cm−3, respectively. Electrochemical impedance spectroscopy analysis showed that the charge transfer resistances differed between the Na salts and other electrolytes. Therefore, the use of a large amount of NaF in the solid electrolyte interphase (SEI) resulted in high charge transfer resistances at the non-graphitizable electrodes. However, there were no apparent differences in the activation energy or reversible capacity. In summary, NaF obstructs the penetration pathway of sodium ions into non-graphitizable carbon, impacting the charge transfer resistance and rate stability of SIBs. Charge–discharge measurements revealed reversible capacities of 260–290 mAh g−1, and the rate performance varied depending on the electrolyte. Therefore, an SEI containing minimal inorganic species, such as NaF, is desirable for efficient sodium-ion insertion into non-graphitizable carbon.
18
Yao, Koffi Pierre, Rownak Jahan Mou e Sattajit Barua. "Electrophoretic Deposition of Chitosan as Synthetic SEI for Silicon Anode: A Model System Investigation". ECS Meeting Abstracts MA2023-01, n. 2 (28 agosto 2023): 523. http://dx.doi.org/10.1149/ma2023-012523mtgabs.
Testo completoAbstract (sommario):
The cycling performance of high-energy silicon (Si) based lithium-ion (Li-ion) battery is greatly hindered by the instability of the solid electrolyte interphase (SEI). Large volume change of Si during (de)-lithiation causes continuous cracking and re-formation of the SEI on the anode surface, eventually resulting in loss of Li inventory and extensive consumption of electrolyte. Our work aims to devise, ex situ, an artificial polymeric SEI that retains its integrity against the large volume expansion of Si (~300%) during lithiation, passivates the anode surface, and thus prolongs the cycling and calendar life of Si-based anodes. Electrophoretic deposition (EPD) was used to coat model silicon thin film surfaces with a layer of chitosan, an ionically conductive cationic polymer, with and without the addition of CH3COOLi in the precursor solution. Morphological study of the coated surface at nano and macroscale via AFM-nanoIR and SEM-EDX show CH3COOLi promotes conformal electrodeposition of chitosan. Electrochemical testing shows a boost in capacity retention and lower charge transfer resistance in the presence of the chitosan synthetic SEI. XPS and ATR-FTIR spectroscopy suggest that CH3COOLi caps the -NH2 group of the deposited chitosan via an amidation reaction which suppresses excess electroreduction of the cell electrolyte. Our work provides a pathway for controlling the chemistry and properties of the SEIs in batteries.
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Wu, Liang-Ting, Santhanamoorthi Nachimuthu, Daniel Brandell, Chia-Ni Tsai, Pei-Hsuan Wang, Yeh-Wei Li e Jyh-Chiang Jiang. "Role of Copper as Current Collectors in the Reductive Reactivity of Polymers for Anode-Free Lithium Metal Batteries - Insights from DFT and AIMD Studies". ECS Meeting Abstracts MA2023-02, n. 5 (22 dicembre 2023): 845. http://dx.doi.org/10.1149/ma2023-025845mtgabs.
Testo completoAbstract (sommario):
Understanding the role of current collectors (CCs) in the reductive reactivity of polymers on Li metal and the resultant solid electrolyte interphase (SEI) formation is essential for improving the performance of anode-free lithium metal batteries (AFLMBs). In this study, we have examined the reactivity of three polymeric hosts: poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(trimethylene carbonate) (PTMC) at Li metal supported on Cu surfaces (Li/Cu) using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. In particular, the effect of copper (Cu) CCs on polymer stability, electronic structure, and their reduction reactions is investigated and compared to that of pure Li (100) surface. Through time-dependent Bader charge transfer analysis, electron transfer is identified as the triggering factor for polymer reduction. Based on the simulations, we find that the Cu CCs have a significant influence on the charge distribution of the Li metals, which increases electron transfer to the polymers and thereby accelerates polymers reduction. This thereby leads to different reaction mechanisms as compared to on Li-metal. The findings suggest that utilization of Cu CCs avoid production of CO molecules and improves the quality of the formed SEI layer. Figure 1
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Ovejas, Victoria, e Angel Cuadras. "Impedance Characterization of an LCO-NMC/Graphite Cell: Ohmic Conduction, SEI Transport and Charge-Transfer Phenomenon". Batteries 4, n. 3 (10 settembre 2018): 43. http://dx.doi.org/10.3390/batteries4030043.
Testo completoAbstract (sommario):
Currently, Li-ion cells are the preferred candidates as energy sources for existing portable applications and for those being developed. Thus, a proper characterization of Li-ion cells is required to optimize their use and their manufacturing process. In this study, the transport phenomena and electrochemical processes taking place in LiCoO2-Li(NiMnCo)O2/graphite (LCO-NMC/graphite) cells are identified from half-cell measurements by means of impedance spectroscopy. The results are calculated from current densities, instead of absolute values, for the future comparison of this data with other cells. In particular, impedance spectra are fitted to simple electrical models composed of an inductive part, serial resistance, and various RQ networks—the parallel combination of a resistor and a constant phase element—depending on the cell. Thus, the evolution of resistances, capacitances, and the characteristic frequencies of the various effects are tracked with the state-of-charge (SoC) at two aging levels. Concretely, two effects are identified at the impedance spectrum; one is clearly caused by the charge transfer at the positive electrode, whereas the other one is presumably caused by the transport of lithium ions across the solid electrolyte interphase (SEI) layer. Moreover, as the cells age, the characteristic frequency of the charge transfer is drastically reduced by a factor of around 70%.
21
Wang, Qi, Rui Zhang, Dan Sun, Haiyan Wang e Yougen Tang. "Manipulating Electrolyte Interface Chemistry Enables High-Performance TiO2 Anode for Sodium-Ion Batteries". Batteries 10, n. 10 (11 ottobre 2024): 362. http://dx.doi.org/10.3390/batteries10100362.
Testo completoAbstract (sommario):
Titanium dioxide (TiO2) has emerged as a candidate anode material for sodium-ion batteries (SIBs). However, their applications still face challenges of poor rate performance and low initial coulomb efficiency (ICE), which are induced by the unstable solid-electrolyte interface (SEI) and sluggish Na+ diffusion kinetics in conventional ester-based electrolytes. Herein, inspired by the electrode/electrolyte interfacial chemistry, tetrahydrofuran (THF) is exploited to construct an advanced electrolyte and reveal the relationship between the improved electrochemical performance and the derived SEI film on TiO2 anode. The robust and homogeneously distributed F-rich SEI film formed in THF electrolyte favors fast interfacial charge transfer dynamics and excellent interfacial stability. As a result, the THF electrolyte endows the TiO2 anode with greatly improved ICE (64.5%), exceptional rate capabilities (186 mAh g−1 at 5.0 A g−1), and remarkable cycling stability. This study elucidates the control of interfacial chemistry by rational electrolyte design and offers insights into the development of high-performance and long-lifetime TiO2 anode.
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Kondo, Yasuyuki, Tomokazu Fukutsuka, Yuko Yokoyama, Yuto Miyahara, Kohei Miyazaki e Takeshi Abe. "Kinetic properties of sodium-ion transfer at the interface between graphitic materials and organic electrolyte solutions". Journal of Applied Electrochemistry 51, n. 4 (7 febbraio 2021): 629–38. http://dx.doi.org/10.1007/s10800-020-01523-z.
Testo completoAbstract (sommario):
AbstractGraphitic materials cannot be applied for the negative electrode of sodium-ion battery because the reversible capacities of graphite are anomalously small. To promote electrochemical sodium-ion intercalation into graphitic materials, the interfacial sodium-ion transfer reaction at the interface between graphitized carbon nanosphere (GCNS) electrode and organic electrolyte solutions was investigated. The interfacial lithium-ion transfer reaction was also evaluated for the comparison to the sodium-ion transfer. From the cyclic voltammograms, both lithium-ion and sodium-ion can reversibly intercalate into/from GCNS in all of the electrolytes used here. In the Nyquist plots, the semi-circles at the high frequency region derived from the Solid Electrolyte Interphase (SEI) resistance and the semi-circles at the middle frequency region owing to the charge-transfer resistance appeared. The activation energies of both lithium-ion and sodium-ion transfer resistances were measured. The values of activation energies of the interfacial lithium-ion transfer suggested that the interfacial lithium-ion transfer was influenced by the interaction between lithium-ion and solvents, anions or SEI. The activation energies of the interfacial sodium-ion transfer were larger than the expected values of interfacial sodium-ion transfer based on the week Lewis acidity of sodium-ion. In addition, the activation energies of interfacial sodium-ion transfer in dilute FEC-based electrolytes were smaller than those in concentrated electrolytes. The activation energies of the interfacial lithium/sodium-ion transfer of CNS-1100 in FEC-based electrolyte solutions were almost the same as those of CNS-2900, indicating that the mechanism of interfacial charge-transfer reaction seemed to be the same for highly graphitized materials and low-graphitized materials each other. Graphic abstract
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Sunderraj, Niranjan, Shankar Raman Dhanushkodi, Ramesh Kumar Chidambaram, Bohdan Węglowski, Dorota Skrzyniowska, Mathias Schmid e Michael William Fowler. "Development of Semi-Empirical and Machine Learning Models for Photoelectrochemical Cells". Energies 17, n. 21 (25 ottobre 2024): 5313. http://dx.doi.org/10.3390/en17215313.
Testo completoAbstract (sommario):
We introduce a theoretical model for the photocurrent-voltage (I-V) characteristics designed to elucidate the interfacial phenomena in photoelectrochemical cells (PECs). This model investigates the sources of voltage losses and the distribution of photocurrent across the semiconductor–electrolyte interface (SEI). It calculates the whole exchange current parameter to derive cell polarization data at the SEI and visualizes the potential drop across n-type cells. The I-V model’s simulation outcomes are utilized to distinguish between the impacts of bulk recombination and space charge region (SCR) recombination within semiconductor cells. Furthermore, we develop an advanced deep neural network model to analyze the electron–hole transfer dynamics using the I-V characteristic curve. The model’s robustness is evaluated and validated with real-time experimental data, demonstrating a high degree of concordance with observed results.
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Schlaier, Jonas, Roman Fedorov, Shixian Huang, Yair Ein-Eli, Michael Schneider, Christian Heubner e Alexander Michaelis. "Electrochemical Characterization of Artificial Solid Electrolyte Interphase Developed on Graphite Via ALD". ECS Meeting Abstracts MA2023-02, n. 60 (22 dicembre 2023): 2909. http://dx.doi.org/10.1149/ma2023-02602909mtgabs.
Testo completoAbstract (sommario):
During formation of Li-ion batteries, a ‘natural’ solid electrolyte interphase (SEI) is formed at the anode side by decomposition products of the electrolyte. The properties of the SEI are extremely decisive for the overall battery properties, such as rate capability and cycling stability. However, the SEI formation consumes Li, leading to so called ‘formation losses’ that can make up to 15% of the theoretical energy density of the battery. Several approaches have been presented to overcome formation losses while preserving excellent overall battery properties. Particularly, electrochemical prelithiation and the application of artificial SEIs prior cell assembly are considered to effectively reduced formation losses while improving the interfacial charge transfer properties and increasing cycling stability. Herein, the authors present an innovative approach of applying a multifunctional artificial SEI on anode material powders via consecutive atomic layer deposition (ALD) cycles. As a model system, graphite powder has been chosen to be modified and characterized. The resulting electrodes show substantially improved electrochemical performance in half cells and full cells, regarding initial capacity loss, CE and cycling stability. Furthermore, model electrodes consisting of a single layer of graphite particles were manufactured, which exclude the effects of a typical composite electrode and therefore reveal the intrinsic properties of the active material. Using this approach, the interfacial kinetics and the rate capability are investigated comparatively between pristine and ALD coated electrodes, revealing the impact of the artificial SEI on the materials level.
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Stich, Michael, Jesus Eduardo Valdes Landa, Isabel Pantenburg, Bernhard Roling e Andreas Bund. "Combined Operando Investigations Reveal Correlation between Formation Parameters and Transport Mechanisms in Solid Electrolyte Interphases of Lithium-Ion Battery Anodes". ECS Meeting Abstracts MA2023-02, n. 5 (22 dicembre 2023): 887. http://dx.doi.org/10.1149/ma2023-025887mtgabs.
Testo completoAbstract (sommario):
Despite its thickness being only in the nanometer range, the solid electrolyte interphase (SEI) of lithium-ion battery anodes has proven to be a crucial component, contributing critically to the battery’s longevity and long-term rate capability. This is due to the SEI’s passivating properties, protecting the battery electrolyte from further decomposition during operation while maintaining a good conductivity for lithium ions to be intercalated into the active anode material. Notwithstanding prolonged scientific efforts, a reliable SEI characterization is still very challenging, due to its fragile and inherently unstable nature which can easily lead to the introduction of artifacts in its evaluation, when dried, rinsed, or exposed to ambient atmospheric conditions. Thus, the relation between SEI formation parameters and the resulting morphological, compositional, and electrochemical properties is still poorly understood. To overcome the limitations of often-employed ex-situ methods, we developed an interlocked combination of several non-destructive operando characterization methods consisting of atomic force microscopy (AFM), electrochemical quartz-crystal microbalance (EQCM) and electrochemical impedance spectroscopy (EIS) to provide a plethora of information on the SEI’s morphological evolution, mass and thickness development and its viscoelastic and electrochemical properties like charge transfer resistance. All this information is gathered in the same electrochemical cell during the SEI formation on carbon model electrodes in typical LIB electrolytes containing 1 M LiPF6 in various carbonate mixtures. The combination of AFM, EQCM and EIS data gives us the opportunity to correlate the different growth modes during formation and resulting compositions of the SEI with its dominant transport mechanisms. Additional redox probe experiments help to further distinguish the transport parameters for lithium ions, solvent molecules, and redox molecules. A better understanding of these correlations allows battery researchers to find optimized SEI formation procedures and SEI forming additives, which reduce the formation duration during battery production and can thus contribute to lowering costs of lithium-ion batteries.
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Yamamoto, Satoshi, Ryotaro Sakakibara, Munekazu Motoyama, Norikazu Ishigaki, Wataru Norimatsu e Yasutoshi Iriyama. "LiPON/Multilayer-Graphene Interface Enables High-Rate Charging and Discharging". ECS Meeting Abstracts MA2023-02, n. 5 (22 dicembre 2023): 839. http://dx.doi.org/10.1149/ma2023-025839mtgabs.
Testo completoAbstract (sommario):
Graphite is the anode-active material commonly used in LIBs. In LIB, solid electrolyte interphase (SEI) is formed by the reduction of the liquid electrolyte, and the SEI plays a role as a passive film. In the charging process, Li ions transport in the liquid electrolyte and SEI, desolvation reactions of Li ions occur, and then Li ions insert into the graphite anode. It has been reported that the desolvation reaction of Li ions is the rate-limiting process[1]. Lithium phosphorous oxynitride glass (LiPON) is a well-known material as a solid electrolyte. However, it has been reported that the electrochemical window of LiPON ranges from 0.68 V to 2.63 V[2]. Therefore, it is possible that the decomposition reaction of LiPON occurs when the electrochemical cell is charged. Since the decomposition products can be a resistance, LiPON that is not easily reduced is required. In this study, we focused on the lithium phosphorus oxynitride glass (LiPON) electrolyte/multilayered graphene (MGr) film interface as an example without the desolvation process. In addition, we have investigated the relationship between LiPON composition ratio, electronic properties, and interfacial resistance by changing the sputtering conditions for LiPON film. Consequently, we found that the charge-transfer resistance at the MGr/LiPON interface was significantly small, although the MGr/LiPON interface was supposed to have inorganic solid electrolyte interphase resulting from the LiPON reduction decomposition. The figure shows a schematic illustration of the Liquid Electrolyte/MGr interface and the LiPON/MGr interface. Figure 1
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Mosallanejad, Behrooz, Mehran Javanbakht, Zahra Shariatinia e Mohammad Akrami. "Phenyl Vinylsulfonate, a Novel Electrolyte Additive to Improve Electrochemical Performance of Lithium-Ion Batteries". Energies 15, n. 17 (26 agosto 2022): 6205. http://dx.doi.org/10.3390/en15176205.
Testo completoAbstract (sommario):
Irreversible capacity fading, originating from the formation of the solid electrolyte interphase (SEI), is a common challenge encountered in lithium-ion batteries (LIBs) containing an electrolyte based on ethylene carbonate (EC). In this research, phenyl vinyl sulfonate (PVS) is examined as a novel electrolyte additive to mitigate this issue and subsequently enhance the cyclic stability of LIBs. As evidenced by density functional theory (DFT) calculations, PVS has a higher reduction potential than that of EC, which is in accordance with the cyclic voltammetry (CV) measurements. Accordingly, the PVS-containing electrolyte demonstrated a reduction peak at ~1.9 V, which was higher than that of the electrolyte without an additive (at ~1.7 V). In contrast to the SEI derived from the reference electrolyte, the one built-in PVS-containing electrolyte was capable of completely inhibiting the electrolyte reduction. In terms of the Raman spectroscopy and electrochemical impedance spectroscopy (EIS) analysis, SEI formation as the result of PVS reduction can lead to less structural disorder in the graphite electrode; the battery with the additive showed less interfacial and charge transfer resistance. The Li/graphite cell with 1 wt % of PVS delivered capacity retention much higher than that of its counterpart without the additive after 35 cycles at 1 C.
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Schmidt-Meinzer, Noah, e Ingo Krossing. "Synthesis and Electrochemical Characterization of Novel Electrolyte Additives for High Performance in Lithium-Ion Batteries with Si-Based Anodes". ECS Meeting Abstracts MA2023-02, n. 65 (22 dicembre 2023): 3093. http://dx.doi.org/10.1149/ma2023-02653093mtgabs.
Testo completoAbstract (sommario):
Silicon is a promising active material for the anode in lithium-ion batteries (LIB), since it enables much higher energy densities than graphite - the state-of the art material for LIB-anodes. However, the utilization of silicon brings many challenges, which originate mainly from the enormous volume change between the lithiated and delithiated state (300%). One of the consequences is a constant re-formation of the solid electrolyte interphase (SEI), which is accompanied by a loss of active Li+. This leads to a strong capacity fading, which results in a very short cycle life. [1] An efficient and economical approach to tackle these problems is the utilization of additives in the electrolyte. Additives are small molecules or salts that decompose during the first cycles of the battery life resulting in an interphase with modified composition and thereby an improved SEI. Depending on the additive the SEI can reduce the impedance of the cell and help to maintain the structural stability of the anode. [2] In this work four new additives were synthesized and electrochemically tested with a silicon-based anode. Improvements regarding capacity retention were found for all additives in half-cell measurements. Hence, after 500 cycles additive 1 showed a 26 % increased capacity retention, while additive 4 induced an improvement of 43 % compared to the base electrolyte. Electrochemical impedance measurements were conducted and simulated directly after the formation as well as after 100 cycles. The resistance of the first semi-circle showed a reduction of 40 % and 26 % after formation and 100 cycles respectively, when the additive 1 is used. The second semi-circle showed no significant change after formation, but a 27 % reduction of resistance after 100 cycles, when the additive 1 is used. The semi-circles can be attributed to the Li ion migration in the SEI. Therefore, the SEI build from the decomposition of additive 1 favours charge-transfer compared to the SEI build from the base electrolyte. Scanning electron microscopy (SEM) images of lithiated and delithiated electrodes show smaller cracks on the surface when using additive 1 compared to the electrode treated with the base electrolyte. This phenomenon shows an increased cohesive force of the new formed SEI mitigating the effects of the enormous volume expansion in the electrode. [1] Zuo X., Zhu J., Müller-Buschbaum P. & Cheng Y.-J. Silicon based lithium-ion battery anodes: A chronicle perspective review. Nano Energy. 31, 213-143; 10.1016/j.nanoen.2016.11.013 (2017) [2] Eshetu, G.G., Zhang, H., Judez, X. et al. Production of high-energy Li-ion batteries comprising silicon-containing anodes and insertion-type cathodes. Nat Commun 12, 5459; 10.1038/s41467-021-25334-8 (2021) Figure 1
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Zheng, Lu, Liang Bin Liu, Xiao Jing Zhou e Yu Zhong Guo. "An Electrochemical Impedance Spectroscopy (EIS) Study of Zn-Doped Li (Ni1/3Co1/3Mn1/3) O2 Cathode Materials in the First Delithiation Process". Advanced Materials Research 833 (novembre 2013): 50–55. http://dx.doi.org/10.4028/www.scientific.net/amr.833.50.
Testo completoAbstract (sommario):
Li (Ni1/3Co1/3Mn1/3) O2 cathode materials doped by Zn were synthesized by a co-precipitation routine, the first delithiation process of the samples with 0-4wt% of Zn doping were studied by electrochemical impedance spectroscopy (EIS) under the polarized voltage of 2.8-4.6V. The fitting results based on EIS data indicate that delithiation reactions happen within the voltage range of 3.7-4.4V ; The resistances of SEI film and charge transfer are both decreased significantly, whereas Li+ diffusion ability through layered crystalline lattice is improved largely with the increase of zinc doping from 0 to 4wt%.
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Genov, Ivan, Alexander Tesfaye, Svetlozar Ivanov e Andreas Bund. "Investigations on the Initial-Stages of Lithium Deposition/Dissolution Processes in Sulfolane Based Electrolytes". ECS Meeting Abstracts MA2023-02, n. 5 (22 dicembre 2023): 833. http://dx.doi.org/10.1149/ma2023-025833mtgabs.
Testo completoAbstract (sommario):
Li metal could be the ideal anode for rechargeable battery technologies, due to its negative redox potential (ca. -3 V vs. SHE), high specific capacity (3860 mAh g−1), and low density (0.534 g cm−3) [1-3]. Recent advances show a new design concept where there are no initial active materials in the anode (no carbon, Si, or Li metal) and the corresponding Li quantity is directly deposited on the current collector during charging. This approach will result in important practical advantages such as enhanced volumetric and gravimetric specific energies, ease of manufacturing and reduced complexity/safety concerns of the recycling process (ideally Li is completely removed in the discharged state). However, the applicability of the Li-metal batteries is constrained by the nonuniform lithium deposition, accompanied by dendrite growth and the formation of dead lithium during long-term cycling, which lead to low Coulombic efficiency and even cell failure [2]. The initial structure and morphology of the Li deposit has a vital influence on the later progression of the Li layer [4]. This underpins the importance of a fundamental understanding of the electrodeposition process. However, the presence of a solid-electrolyte interphase (SEI) makes such investigations difficult, since after the transport of the Li ions through the SEI, a subsequent charge transfer and nucleation growth process at the substrate-SEI interface, instead of substrate-liquid electrolyte interface occurs. This contribution will discuss lithium electrodeposition in a sulfolane based, localized high concentrated electrolyte system. Possible phase formation mechanisms as well as kinetic and thermodynamic aspects during the initial stages of the process are studied by classical electrochemical methods (Fig. 1, left). Furthermore, the mass-charge balance during deposition and stripping was monitored (Fig. 1, right) via in-situ microgravimetry (electrochemical quartz crystal microbalance). In the contribution we will discuss these transients in terms of lithium layer growth and SEI formation. References: [1] X. Cheng et al., (2017) Chemical Reviews, 117 (15), p. 10403-10473. [2] J. Cui et al., (2017) Chinese Chemical Letters, 28 (12), p. 2171-2179. [3] Z. Hu et al., (2020) Frontiers in chemistry 8, p. 409. [4] A. Pei et al., (2017) Nano Letters, 17 (2), p. 1132–1139. Figure 1
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Aboonasr Shiraz, Mohammad Hossein, Erwin Rehl, Hossein Kazemian e Jian Liu. "Durable Lithium/Selenium Batteries Enabled by the Integration of MOF-Derived Porous Carbon and Alucone Coating". Nanomaterials 11, n. 8 (31 luglio 2021): 1976. http://dx.doi.org/10.3390/nano11081976.
Testo completoAbstract (sommario):
Lithium-selenium (Li-Se) batteries are a promising energy storage system in electric vehicles due to their high capacity and good kinetics. However, the shuttle effect issue, caused by polyselenide dissolution from the Se cathode, has hampered the development of Li-Se batteries. Herein, we developed a facile preparation of porous carbon from a metal-organic framework (MOF) to confine Se (Se/CZIF) and protect the Se/CZIF composite with an alucone coating by molecular layer deposition (MLD). The optimal alucone coated Se/CZIF cathode prepared exhibits a one-step reversible charge/discharge process in the carbonate electrolytes. The inhibition of polyselenide dissolution is credited with the improved electrochemical performance, formation of thin and stable solid electrolyte interphase (SEI) layers, and a reduction in charge transfer resistance, thus improving the overall performance of Li-Se batteries.
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Joshi, Prerna, Katsuhito Iwai, Sai Gourang Patnaik, Raman Vedarajan e Noriyoshi Matsumi. "Reduction of Charge-Transfer Resistance via Artificial SEI Formation Using Electropolymerization of Borylated Thiophene Monomer on Graphite Anodes". Journal of The Electrochemical Society 165, n. 3 (2018): A493—A500. http://dx.doi.org/10.1149/2.0141803jes.
Testo completo
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Flasque, Miguel, Albert Nguyen Van Nhien, Davide Moia, Piers R. F. Barnes e Frédéric Sauvage. "Consequences of Solid Electrolyte Interphase (SEI) Formation upon Aging on Charge-Transfer Processes in Dye-Sensitized Solar Cells". Journal of Physical Chemistry C 120, n. 34 (23 agosto 2016): 18991–98. http://dx.doi.org/10.1021/acs.jpcc.6b05977.
Testo completo
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Cora, Saida, e Niya Sa. "Mechanisms of Si Stabilization for Future Anode Design". ECS Meeting Abstracts MA2022-02, n. 4 (9 ottobre 2022): 359. http://dx.doi.org/10.1149/ma2022-024359mtgabs.
Testo completoAbstract (sommario):
Silicon owing to its abundance, low working potential and high theoretical specific capacity has been regarded as one of the promising anode materials for the next generation lithium-ion batteries (LIBs). The bottleneck of Si anode practical application is its large volume variation and formation of reactive silicide species at the anode/electrolyte interface during lithiation which result in continuous SEI formation and consumption of active electrolyte components. The new electrolyte design strategies have shown to stabilize the Si electrode via an in situ electrochemical formation of a metastable ternary Li-Mg-Si phase. In this study, the effect of electrolyte modification on the dynamic formation of solid electrolyte interphase (SEI) on Si anode is investigate in the pre-lithiation versus post-lithiation stages of electrochemical cycling. In addition, combined EQCM-EIS are used to investigate the charge transfer mechanism and the resistivity of the surface film at various stages of cycling. The understanding of the stabilization effect of Mg salt on Si surface chemistry may have a great impact on the development of Si-based anodes for lithium-ion batteries.
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Nesterova, Inara, Liga Britala, Anatolijs Sarakovskis, Beate Kruze, Gunars Bajars e Gints Kucinskis. "The Impact of Graphene in Na2FeP2O7/C/Reduced Graphene Oxide Composite Cathode for Sodium-Ion Batteries". Batteries 9, n. 8 (3 agosto 2023): 406. http://dx.doi.org/10.3390/batteries9080406.
Testo completoAbstract (sommario):
This study presents a thorough investigation of Na2FeP2O7 (NFP) cathode material for sodium-ion batteries and its composites with carbon and reduced graphene oxide (rGO). Our findings demonstrate that rGO sheets improve cycling performance in NFP/C/rGO composite in the absence of solid electrolyte interphase (SEI)-stabilizing additives. However, once SEI is stabilized with the help of fluoroethylene carbonate electrolyte additive, NFP with carbon additive (NFP/C) exhibits a superior electrochemical performance when compared to NFP/rGO and NFP/C/rGO composites. The decreases in capacity and rate capability are proportional to the amount of rGO added, and lead to an increase in overvoltage and internal resistance. Based on our results, we attribute this effect to worsened sodium kinetics in the bulk of the electrode—the larger ionic radius of Na+ hinders charge transfer in the presence of rGO, despite the likely improved electronic conductivity. These findings provide a compelling explanation for the observed trends in electrochemical performance and suggest that the use of rGO in Na-ion battery electrodes may present challenges associated with ionic transport along and through rGO sheets.
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Oroszová, Lenka, Dávid Csík, Gabriela Baranová, Gábor Bortel, Róbert Džunda, László Temleitner, Mária Hagarová, Ben Breitung e Karel Saksl. "Utilizing High-Capacity Spinel-Structured High-Entropy Oxide (CrMnFeCoCu)3O4 as a Graphite Alternative in Lithium-Ion Batteries". Crystals 14, n. 3 (24 febbraio 2024): 218. http://dx.doi.org/10.3390/cryst14030218.
Testo completoAbstract (sommario):
In the realm of advanced anode materials for lithium-ion batteries, this study explores the electrochemical performance of a high-entropy oxide (HEO) with a unique spinel structure. The equiatomic composition of CrMnFeCoCu was synthesized and subjected to a comprehensive materials characterization process, including X-ray diffraction and microscopy techniques. The multicomponent alloy exhibited a multiphase structure, comprising two face-centered cubic (FCC) phases and an oxide phase. Upon oxidation, the material transformed into a spinel oxide with a minor presence of CuO. The resulting high-entropy oxide demonstrated excellent electrochemical behavior when utilized as an anode material. Cyclic voltammetry revealed distinctive reduction peaks attributed to cation reduction and solid electrolyte interphase (SEI) layer formation, while subsequent cycles showcased high reversibility. Electrochemical impedance spectroscopy indicated a decrease in charge transfer resistance during cycling, emphasizing the remarkable electrochemical performance. Galvanostatic charge/discharge tests displayed characteristic voltage profiles, with an initial irreversible capacity attributed to SEI layer formation. The HEO exhibited promising rate capability, surpassing commercial graphite at higher current densities. The battery achieved 80% (275 mAh g−1) of its initial stable capacity at a current density of 500 mA g−1 by the 312th cycle. Post-mortem analysis revealed structural amorphization during cycling, contributing to the observed electrochemical behavior. This research highlights the potential of HEOs as advanced anode materials for lithium-ion batteries, combining unique structural features with favorable electrochemical properties.
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Huang, Yan Dan, Ying Bin Lin e Zhi Gao Huang. "Enhanced Electrochemical Performances of LiFePO4/C Cathode Materials by Deposited with Ge Film". Advanced Materials Research 936 (giugno 2014): 480–85. http://dx.doi.org/10.4028/www.scientific.net/amr.936.480.
Testo completoAbstract (sommario):
LiFePO4/C-Ge electrodes were prepared with vacuum thermal evaporation deposition by depositing Ge films on as-prepared LiFePO4/C electrodes. The effect of Ge film on the electrochemical performances of LiFePO4/C cells was investigated systematically by charge/discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. It was found that Ge-film-surface modified LiFePO4/C showed excellent electrochemical performances compared to that of the pristine one in terms of cyclability and rate capability. At 60°C, LiFePO4/C-Ge film exhibited outstanding cyclability with less than 5% capacity fade after 50 cycles while the pristine one suffers 15%. Analysis from the electrochemical measurements showed that the presence of Ge film on the LiFePO4/C electrode would protect active material from HF generated by the decomposition of LiPF6 in the electrolyte and stabilize the surface structure of active material during the charge and discharge cycle. Electrochemical impedance spectroscopy (EIS) results indicated that Ge film mainly reduced the charge transfer resistance Rct of LiFePO4/C electrode, resulting from the suppression of the solid electrolyte interfacial (SEI) film.
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Kim, Tae Hyeon, Sung Su Park, Min Su Kang, Ye Rin Kim, Ho Seok Park, Hyun-seung Kim e Goojin Jeong. "Accelerated Degradation of SiO/NCM Cell Quick Rechargeability Due to Depth-of-Discharge Range Dependent Failure Induced Li Dendrite Formation". Journal of The Electrochemical Society 169, n. 2 (1 febbraio 2022): 020562. http://dx.doi.org/10.1149/1945-7111/ac53cf.
Testo completoAbstract (sommario):
The failure of the quick rechargeability of SiO-based lithium-ion batteries is examined based on different SOC ranges pre-cycling. In detail, the effect of the SiO electrode during normal C-rate applied cycling on the subsequent quick charge is analyzed. The degradation of the SiO electrode is greatly influenced by the design of cycling SOC range of the SiO/NCM811 cell, and severe mechanical and solid electrolyte interphase degradation of the SiO electrode occurred with highly utilized SiO electrodes, resulting in Li plating on the SiO surface under quick charge conditions due to the low open-circuit voltage of SiO electrode and high charge transfer resistance, which is derived from the Li-trap at SiO and subsequent SEI development and electrode crack. The degraded SiO electrode is vulnerable to Li plating at high C-rate applications; hence, the pre-cycling condition of the SiO electrode influences the quick rechargeability of the SiO/NCM811 cell. Consequently, proper manipulation of the cycling range of SiO-based cells should be conducted to enhance the durability of SiO-based quick rechargeable cells.
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Loghavi, Mohammad Mohsen, Saeed Bahadorikhalili, Najme Lari, Mohammad Hadi Moghim, Mohsen Babaiee e Rahim Eqra. "The Effect of Crystalline Microstructure of PVDF Binder on Mechanical and Electrochemical Performance of Lithium-Ion Batteries Cathode". Zeitschrift für Physikalische Chemie 234, n. 3 (26 marzo 2020): 381–97. http://dx.doi.org/10.1515/zpch-2018-1343.
Testo completoAbstract (sommario):
AbstractIn this paper, the effect of the crystalline microstructures of polyvinylidene fluoride (PVDF), as cathode binder, on mechanical and electrochemical properties of the cathode, and on the cell performance is investigated. The crystalline phases of the PVDF films prepared at different temperatures are determined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) and also mechanical strength of PVDF films evaluated by a tensile test. The cathodes were prepared at altered temperatures to achieve different PVDF phases. The effect of various crystalline phases on the cathode performance was studied. The obtained cathodes were analyzed by scanning electron microscope (SEM), contact angle measurement, and adhesion test. The electrochemical performance of the cathodes was evaluated by charge-discharge cycling test and AC impedance spectroscopy. Mechanical tests results showed that the cathode which is prepared at 60 °C has the best adhesion and mechanical stability. In addition, the charge-discharge cycling studies showed that this cathode has the highest capacity efficiency. AC impedance spectroscopy illustrated that this electrode has the lowest charge transfer resistance and SEI resistance.
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Vlčková, Zuzana, Martin Jindra, Gabriela Soukupová, Tomáš Lapka, Farjana Sonia, Martin Müller, Jiří Červenka, Antonín Fejfar, Fatima Hassouna e Otakar Frank. "In Situ Raman Spectroelectrochemical Investigation of Composite Si Nanoparticle-Based Anode for Li-Ion Batteries during (de)Lithiation Process". ECS Meeting Abstracts MA2023-02, n. 5 (22 dicembre 2023): 823. http://dx.doi.org/10.1149/ma2023-025823mtgabs.
Testo completoAbstract (sommario):
The key degradation processes in the composite anode for the Li-ion batteries (LIBs) prepared using Si nanoparticles (SiNPs) with two types of a conductive carbon-based matrix [carbon black (CB) and carbonized polypyrrole (CPPy)] were studied by in situ Raman spectroelectrochemistry (SEC). This combined technique provides non-destructive and real-time monitoring of the chemical and structural changes that occur during battery operation. These processes, such as the crystal lattice changes (expansion/contraction) and possible degradation/amorphization of silicon, the solid electrolyte interphase (SEI) layer formation on the electrode surface during the charge/discharge reactions, and the stability of the carbon-based matrix, significantly affect the performance of Si-based LIBs in many ways. Especially, the large silicon volume expansion (more than 300%) and associated stress cause mechanical instability resulting in rapid capacity fading. To overcome this challenge, various strategies have been proposed, including the use of CPPy as a conductive matrix to prevent large volumetric changes and also provide a pathway for electron transfer. This study investigates the initial degradation mechanisms such as the formation of the SEI layer, as well as possible structural changes caused by the volume expansion of SiNPs. The shift of the first-order Raman peak of Si at 521 cm-1 which is assigned to crystalline silicon is related to the stress evolution in nanoparticles caused by the (de)lithiation-induced stress (tensile-to-compressive transition) in SiNPs and the native oxide on their surface. Additionally, the detailed in situ Raman measurement of the first lithiation cycle allowed us to detect the decomposition of the electrolyte (LiPF6 in EC/DMC) close to the Si surface which is associated with SEI layer formation. A decrease in the intensity of the Raman vibrational modes (700–1050 cm−1) of EC/DMC corresponding to the decomposition of the electrolyte was observed at reduction potentials of 0.8 V and 0.3 V vs. Li/Li+ corresponding to the same potentials determined by cyclic voltammetry. The Si-based anode containing CPPy as active carbon showed better electrochemical properties (higher charge/discharge capacity and cycling stability) in Li-ion batteries than Si/CB despite the higher conductivity of the latter. The correlation between the chemical structure of the active carbon and the electrochemical properties of the resulting Si-based anodes will be discussed. Acknowledgment: This work was supported by the Czech National Foundation, Project No. 21–09830S.
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Gossage, Zachary Tyson, Nanako Ito, Tomooki Hosaka, Ryoichi Tatara e Shinichi Komaba. "Understanding the Development and Properties of SEI in Concentrated Aqueous Electrolytes Via Scanning Electrochemical Microscopy". ECS Meeting Abstracts MA2023-02, n. 60 (22 dicembre 2023): 2900. http://dx.doi.org/10.1149/ma2023-02602900mtgabs.
Testo completoAbstract (sommario):
Solid-electrolyte interphases (SEI) are essential to the stability of high voltage lithium-ion batteries (LIBs) where they act as a protective barrier that prevents electrolyte decomposition during charge-discharge and during storage of the energy. Within emerging water-in-salt electrolytes (WISE), the SEI are thought to play a similar role in preventing electrolyte decomposition and expanding the potential window.(1, 2) The SEI reported in WISE are derived from the electrolyte ions, producing inorganic SEI (e.g. LiF) of similar thickness to non-aqueous batteries.(1) Others suggest the superconcentrated regimes promote anion reduction and shift its reduction potential at similar or more positive potentials to hydrogen evolution. However, our knowledge on the SEI found in concentrated aqueous electrolytes and their properties remains quite limited. Furthermore, WISE full cells can access >1000 cycles at high rates, but their capacities and retention are still heavily lacking compared with commercial LIBs.(2) Improving our understanding of the WISE-based SEI formation process, its stabilization, and prevention of gas evolution are key to achieving higher performing aqueous batteries. Herein, we explore the use of advanced scanning electrochemical microscopy (SECM) methods(3) to characterize an SEI within a highly concentrated K(FSA)0.6(OTf)0.4 electrolyte. Focusing on a 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) composite electrode, we use both ex situ, approach curves as well as in situ single spot measurements to analyze SEI formation (Figure 1a). The approach curves were collected before and after galvanostatic cycling by using a three-electrode cell that could easily be converted between closed (cycling) and open-cell (SECM) measurements. After cycling, we observed passivating SEI structures with electron transfer rates comparable to those found in LIBs (Figure 1b). At the same time, our results indicated the SEI deposition was discontinuous with some regions showing reactivity comparable to an uncycled electrode. We noted an increase in roughness with cycling, which could produce some of the more reactive regions exposed at the electrode surface. Thereafter, we conducted in situ measurements at a constant distance from the PTCDI surface.(4) During the first cycle, we observed a reversible/transient decrease in the feedback current at ~ -0.7 V vs. Ag/AgCl, far positive to H2 evolution (Figure 1c,d). In addition, more stable passivation was observed when the PTCDI electrode reached more negative potentials accessing the second redox process of PTCDI (Figure 1c,e). As the electrode reached potentials more negative to -1.3 V, we observed significant hydrogen evolution. Our results were further confirmed with operando electrochemical mass spectrometry (OEMS). OEMS showed similar potentials for evolving hydrogen as well as the evolution of other gases indicative of SEI formation. In all, our interfacial SECM analyses combined with traditional battery measurements and OEMS provides direct quantification of the passivating properties of the SEI as well as identification of local and bulk gas evolution that can be expanded for other emerging aqueous systems. References 1 L. Suo, et al., Science, 2015, 350, 938-943. 2 L. Droguet, et al., Adv. Energy Mater., 2020, 10, 2002440. 3 Gossage, Z.T., et al., "Application to Batteries and Fuel Cells." Scanning Electrochemical Microscopy. CRC Press, 2022. 481-512. 4 G. Zampardi, et al., RSC Advances, 2015, 5, 31166-31171. Figure 1
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Lee, Dongsoo, Seho Sun, Chanho Kim, Jeongheon Kim, Keemin Park, Jiseok Kwon, Dowon Song, Kangchun Lee, Taeseup Song e Ungyu Paik. "Highly reversible cycling with Dendrite-Free lithium deposition enabled by robust SEI layer with low charge transfer activation energy". Applied Surface Science 572 (gennaio 2022): 151439. http://dx.doi.org/10.1016/j.apsusc.2021.151439.
Testo completo
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Eldesoky, A., E. R. Logan, A. J. Louli, Wentao Song, Rochelle Weber, Sunny Hy, Remi Petibon et al. "Impact of Graphite Materials on the Lifetime of NMC811/Graphite Pouch Cells: Part II. Long-Term Cycling, Stack Pressure Growth, Isothermal Microcalorimetry, and Lifetime Projection". Journal of The Electrochemical Society 169, n. 1 (1 gennaio 2022): 010501. http://dx.doi.org/10.1149/1945-7111/ac42f1.
Testo completoAbstract (sommario):
Part II of this 2-part series examines the impact of competitive graphite materials on NMC811 pouch cell performance using Ultra-High Precision Coulometry (UHPC), isothermal microcalorimetry, and in-situ stack growth. A simple lifetime projection of the best NMC811/graphite cells as a function of operating temperature is made. We show that graphite choice greatly impacts fractional fade, while fractional charge endpoint capacity slippage was largely unchanged due to identical cathodes. We show that an increase in graphite 1st cycle efficiency due to limited redox-active sites—favourable for minimizing Li inventory loss—is concomitant with an increase in negative electrode charge transfer resistance. Further, we demonstrate that cells with competitive artificial graphites (AG) have a lower parasitic heat flow (∼0.060 mW A−1 h−1 at 40 oC) compared to cells with natural graphites (NG), and that the cells with the AGs had minimal stack thickness change with cycling. Finally, we model SEI growth for NMC811 cells limited to 4.06 V with the square-root time model, and project that the best NMC811/graphite cells here can have decades-long lifetimes at 20 –30 °C when Li plating is avoided. Such cells are excellent candidates for grid storage applications where energy density is less important compared to long lifetime.
44
Jayawardana, Chamithri, Nuwanthi Dilhari Rodrigo e Brett L. Lucht. "(Invited) Lithium Tetrafluoroborate Based Ester Electrolyte System for Wide Operating Temperatures Ingraphite/ Lini 0.6 Co 0.2 Mn 0.2 O 2 Cells". ECS Meeting Abstracts MA2023-01, n. 38 (28 agosto 2023): 2237. http://dx.doi.org/10.1149/ma2023-01382237mtgabs.
Testo completoAbstract (sommario):
As Lithium ion batteries (LIB) are utilized in wider scale of applications, operation at a wide range of operating temperatures without a penalty to the energy density is desired. Current LIB only produces a fraction of the room temperature capacity when operated at subzero temperatures. Optimization of the electrolyte composition has long been considered a way of improving low temperature battery performance, as the electrolyte dictates the ionic mobility and the stability of the solid electrolyte interface (SEI), which in turn determine the Li ion intercalation kinetics and cycle life of the cell. Different operating temperatures has different demands from the electrolyte. For room temperature performance, formation of a stable solid electrolyte interface is thought to dictate the capacity and the cycle life of a cell. For low temperature performance, Li ion transport properties and charge-transfer polarization may have a dominant effect on cycling performance. Therefore, in this work, a novel electrolyte system was developed that included lithium tetrafluoroborate and methyl acetate for good low temperature performance and different additives were incorporated to this system to improve the room temperature performance by formation of a stable SEI.
45
Feng, Deshi, Ruiling Zheng, Li Qiao, Shiteng Li, Fengzhao Xu, Chuangen Ye, Jing Zhang e Yong Li. "Metal–Organic Framework-Derived Co9S8 Nanowall Array Embellished Polypropylene Separator for Dendrite-Free Lithium Metal Anodes". Polymers 16, n. 13 (5 luglio 2024): 1924. http://dx.doi.org/10.3390/polym16131924.
Testo completoAbstract (sommario):
Developing a reasonable design of a lithiophilic artificial solid electrolyte interphase (SEI) to induce the uniform deposition of Li+ ions and improve the Coulombic efficiency and energy density of batteries is a key task for the development of high-performance lithium metal anodes. Herein, a high-performance separator for lithium metal anodes was designed by the in situ growth of a metal–organic framework (MOF)-derived transition metal sulfide array as an artificial SEI on polypropylene separators (denoted as Co9S8-PP). The high ionic conductivity and excellent morphology provided a convenient transport path and fast charge transfer kinetics for lithium ions. The experimental data illustrate that, compared with commercial polypropylene separators, the Li//Cu half-cell with a Co9S8-PP separator can be cycled stably for 2000 h at 1 mA cm−2 and 1 mAh cm−2. Meanwhile, a Li//LiFePO4 full cell with a Co9S8-PP separator exhibits ultra-long cycle stability at 0.2 C with an initial capacity of 148 mAh g−1 and maintains 74% capacity after 1000 cycles. This work provides some new strategies for using transition metal sulfides to induce the uniform deposition of lithium ions to create high-performance lithium metal batteries.
46
Xu, Xia, Wei Zeng, Fu-Sheng Liu, Zheng-Tang Liu e Qi-Jun Liu. "First-principles calculations of the structural, elastic, mechanical, electronic and optical properties of monoclinic Hf4CuSi4". International Journal of Modern Physics B 34, n. 06 (25 febbraio 2020): 2050035. http://dx.doi.org/10.1142/s0217979220500356.
Testo completoAbstract (sommario):
In this paper, the structural, electronic, elastic, mechanical and optical properties of monoclinic [Formula: see text] are studied using the first-principles density functional theory (DFT). The calculated structural parameters are consistent with the experimental data. The elastic constants of [Formula: see text] structures are calculated, indicating that [Formula: see text] shows mechanical stability and elastic anisotropy. According to the [Formula: see text] and Poisson’s ratio, monoclinic [Formula: see text] shows a brittle manner. The energy band structure, density of states, charge transfers and bond populations are given. And the band structure shows that the material is a metal conductor. Moreover, the optical properties and optical anisotropy of [Formula: see text] are shown and analyzed.
47
Hossain, Md Jamil, Qisheng Wu, David C. Bock, Amy C. Marschilok, Kenneth J. Takeuchi, Esther S. Takeuchi e Yue Qi. "Designing Localized High Concentration Electrolytes Based on Fluorinated Solvents for Lithium-Ion Batteries". ECS Meeting Abstracts MA2023-01, n. 2 (28 agosto 2023): 650. http://dx.doi.org/10.1149/ma2023-012650mtgabs.
Testo completoAbstract (sommario):
Reduction at the anode can affect electrolyte decomposition, solid electrolyte interphase (SEI) formation and growth, and thus the lithium solvation/de-solvation near the SEI, and ultimately lead to various perilous side reactions such as inactive lithium formation. Lithium ions solvated in the electrolyte solution along with salt anions diffuse towards the surface of the electrode. At the charged surface, these solvated ions can undertake different pathways leading to various reductive decomposition products to subsequently form the SEI. The transfer of electrons from the electrode to the salt anions form inorganic SEI products. The SEI layer gradually thickens during repeated charge/discharge cycles due to electron exposure to electrolyte or electrolyte diffusion to the anode surface. This gradual thickening of SEI layer decreases active lithium ions, solvents, and salts and increases cell resistance and lowers the cell capacity and Coulombic efficiency. Essentially, the choice of electrolytes has a significant influence on the formation of an SEI and its underlying chemical and mechanical properties. Optimizing the electrolytes is crucial for an SEI formation since the properties of the SEI significantly affect the lithium-ion batteries’ cyclability, life time, capacity retention, high power density, rate capability, and safety. One approach of stabilizing the SEI is to utilize an electrolyte with high concentration of salt, also known as High-Concentration Electrolytes (HCEs). This approach modifies the Li+ solvation structure to form contact ion pairs (CIP) and aggregates (AGG) while decreasing solvent-separated ion pairs (SSIPs) so that the salt anion, such as FSI-, is preferentially decomposed to form a robust LiF-rich SEI. LiF is considered a beneficial SEI component to block electron transport. By introducing a diluent (a non-solvating solvent) in the HCE to form Localized High Concentration Electrolyte (LHCE), the disadvantages of the HCE, such as low ionic conductivity, high viscosity and high cost, can be minimized while retaining the highly concentrated salt-solvent clusters as they are in the HCE. LHCEs based on fluorinated solvents and diluents can further stabilize the electrode-electrolyte interface. Recent studies showed that the presence of fluorine in the SEI, either in the form of simple inorganic fluorides (LiF) or organofluoro-moieties, brought positive impacts such as expanded electrochemical stability window and high ionic transport. Fluorinated solvents can shift the oxidation stability to a higher voltage compared to their nonfluorinated counterparts. Fluorinated electrolytes enable a high lithium plating Coulombic efficiency and suppresses lithium dendrite formation to a greater extent. In this work we focused on identifying the selection rules for the diluent for designing LHCEs to preserve or improve the local high salt concentration clusters to facilitate the formation of an inorganic rich anion derivative film on the anode as well as to enhance ionic conductivity to enable fast charging. Some of the important properties to consider while selecting a diluent are: - diluent molecules must offer little or no solubility to the salt so that they have minimal participation in the solvation clusters, they must be readily miscible with the solvating solvent so that they dissolve and remove some solvent molecules from the clusters; effectively increasing the salt concentration in the solvation clusters, diluents should be distributed on the periphery of salt-solvent clusters, diluents should have low viscosity, to reduce the overall viscosity of the formulated electrolyte, which in turn improves the ionic conductivity since the low viscosity of diluents allow for higher mobility of the ionic clusters. We analyzed LHCEs consisting of different diluents and diluent molar ratios in a comparative fashion to understand their properties in retaining or improving the structures of the high concentration salt-solvent clusters and improving ionic conductivity. We varied the diluent molar ratio to understand its relationship to increasing salt concentration gradients in the center of the solvent-salt clusters. We also analyzed the relationship between diluent molar ratio and ionic conductivity and found that an optimum diluent molar ratio exists for which the ionic conductivity can be maximized. Our findings serve as design guidelines for practical applications of LHCEs.
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Kurc, Beata, Marita Pigłowska e Łukasz Rymaniak. "The Electrochemical Stability of Starch Carbon as an Important Property in the Construction of a Lithium-Ion Cell". Entropy 23, n. 7 (5 luglio 2021): 861. http://dx.doi.org/10.3390/e23070861.
Testo completoAbstract (sommario):
This paper shows use of starch-based carbon (CSC) and graphene as the anode electrode for lithium-ion cell. To describe electrochemical stability of the half-cell system and kinetic parameters of charging process in different temperatures, electrochemical impedance spectroscopy (EIS) measurement was adopted. It has been shown that smaller resistances are observed for CSC. Additionally, Bode plots show high electrochemical stability at higher temperatures. The activation energy for the SEI (solid–electrolyte interface) layer, charge transfer, and electrolyte were in the ranges of 24.06–25.33, 68.18–118.55, and 13.84–15.22 kJ mol−1, respectively. Moreover, the activation energy of most processes is smaller for CSC, which means that this electrode could serve as an eco-friendly biodegradable lithium-ion cell element.
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Reuter, Lennart, Robert Morasch, Jonas Dickmanns, Filippo Maglia, Roland Jung e Hubert Andreas Gasteiger. "Temperature Dependent Formation of the Graphite SEI with Vinylene Carbonate Electrolyte Additive". ECS Meeting Abstracts MA2022-01, n. 2 (7 luglio 2022): 432. http://dx.doi.org/10.1149/ma2022-012432mtgabs.
Testo completoAbstract (sommario):
The charge/discharge efficiency and the cycle life of lithium-ion batteries (LiBs) depends on a large number of competing interfacial processes. Probably the best-known interface in LiBs is the solid-electrolyte-interphase (SEI), which is a passivating layer formed at the negative electrode by electrolyte decomposition during the first cycles.[1–3] Since the SEI stability is a deciding factor with regards to cycle life, understanding and improving the SEI formation process is crucial. In order to yield an effective SEI, commercial battery cells undergo an extensive so-called formation procedure after cell assembly, which generally consist of multiple voltage-holds and current-steps at various temperatures.[4,5] During the first cycles of a LiB, the SEI is generated by the reduction products of the commonly used carbonate-based electrolyte components, such as ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC).[6,7] Additionally, electrolyte additives are commonly added to form an SEI layer with increased cycling stability and reduced irreversible capacity loss during the first cycle.[6,8–10] Among a variety of additives, vinylene carbonate (VC) is the most prominent. Since the reduction of VC initiates at higher reduction potentials compared to alkyl carbonate solvents (e.g., EC), it is reduced preferentially during the first charge and thus strongly affects the SEI composition.[6,11] In the present study we investigated the effect of the formation temperature in a range between 10-60 °C on the performance characteristics of full-cells with a graphite anode (MAGE) and an NCM831205 cathode as well as of MAGE/Li half-cells, both with LP572 (1 M LiPF6 in EC:EMC 3:7wt/wt + 2wt% VC) electrolyte. These include the first-cycle irreversible capacity loss, the negative electrode impedance build-up, the gas evolution during formation, the rate capability, and the cycle life. Employing electrochemical impedance spectroscopy using a µ-reference electrode allowed us to determine the graphite intercalation resistance (R Int), representing the sum of the SEI resistance (R SEI) and of the charge transfer resistance (R CT), after two 0.1C formation cycles at a given temperature. The impedance spectrum was recorded at 25 °C and 40% SOC referenced to 190 mAh/gNCM reversible capacity. As depicted in Figure 1, both R Int of the graphite electrode in the MAGE/NCM83125 full-cell and the first-cycle irreversible Li-loss determined a MAGE/Li half-cell increase with increasing formation temperature. Additionally, on-line electrochemical mass spectrometry (OEMS) was applied to identify and quantify the gaseous reduction products for LP572 in a MAGE/NCM831205 full-cell during one 0.1C formation cycle at different temperatures. As displayed in Figure 1, the relative increase of the total gas evolved, which is the sum of hydrogen, ethylene, carbon monoxide, and carbon dioxide, follows the relative increase of the intercalation resistance. Next to the overall gas amounts, changes in the quantity of the individual gases give insights into the highly temperature dependent reduction mechanisms of VC. Acknowledgement: The authors thank BMW AG for their financial support. References: [1] E. Peled, J. Electrochem. Soc. 1979, 126, 2047–2051. [2] E. Peled, S. Menkin, J. Electrochem. Soc. 2017, 164, 1703–1719. [3] K. Edström, M. Herstedt, D. P. Abraham, J. Power Sources 2006, 153, 380–384. [4] T. Miura, S. Cottte, K. Masanori, Lithium-Ion Battery Formation Process, 2018, WO 2018/153449 Al. [5] S. Amiruddin, B. Li, High Capacity Lithium Ion Battery Formation Protocol and Corresponding Batteries, 2015, US 9,159,990 B2. [6] B. Zhang, M. Metzger, S. Solchenbach, M. Payne, S. Meini, H. A. Gasteiger, A. Garsuch, B. L. Lucht, J. Phys. Chem. C 2015, 119, 11337–11348. [7] B. Strehle, S. Solchenbach, M. Metzger, K. U. Schwenke, H. A. Gasteiger, J. Electrochem. Soc. 2017, 164, A2513–A2526. [8] D. Pritzl, S. Solchenbach, M. Wetjen, H. A. Gasteiger, J. Electrochem. Soc. 2017, 164, A2625–A2635. [9] T. Taskovic, L. Thompson, A. Eldesoky, M. Lumsden, J. R. Dahn, J. Electrochem. Soc. 2021, DOI 10.1149/1945-7111/abd833. [10] M. Nie, J. Demeaux, B. T. Young, D. R. Heskett, Y. Chen, A. Bose, J. C. Woicik, B. L. Lucht, J. Electrochem. Soc. 2015, 162, A7008–A7014. [11] K. U. Schwenke, S. Solchenbach, J. Demeaux, B. L. Lucht, H. A. Gasteiger, J. Electrochem. Soc. 2019, 166, A2035–A2047. Figure 1 . Formation temperature dependent relative increase (normalized to the formation at 10 °C) of the first-cycle irreversible Li-loss (black lines and dots) determined in MAGE/Li half-cells, of the intercalation resistance R Int at 25 °C and 40% SOC after two 0.1C formation cycles (yellow lines and dots) determined in MAGE/NCM8311205 full-cells with a µ-reference electrode, and of the total amount of gas evolved (sum of H2, C2H4, CO, and CO2; blue lines and dots) after one 0.1C formation cycle determined in a MAGE/NCM831205 OEMS cell. Figure 1
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Hubbard, Christopher G., L. Jared West, Juan Diego Rodriguez-Blanco e Samuel Shaw. "Laboratory study of spectral induced polarization responses of magnetite — Fe2+ redox reactions in porous media". GEOPHYSICS 79, n. 1 (1 gennaio 2014): D21—D30. http://dx.doi.org/10.1190/geo2013-0079.1.
Testo completoAbstract (sommario):
Spectral induced polarization (SIP) phase anomalies in field surveys at contaminated sites have previously been shown to correlate with the occurrence of chemically reducing conditions and/or semiconductive minerals, but the reasons for this are not fully understood. We report a systematic laboratory investigation of the role of the semiconductive mineral magnetite and its interaction with redox-active versus redox-inactive ions in producing such phase anomalies. The SIP responses of quartz sand with 5% magnetite in solutions containing redox-inactive [Formula: see text] and [Formula: see text] versus redox-active [Formula: see text] were measured across the pH ranges corresponding to adsorption of these metals to magnetite. With redox inactive ions [Formula: see text] and [Formula: see text], SIP phase response showed no changes across the pH range 4–10, corresponding to their adsorption, showing [Formula: see text] anomalies peaking at [Formula: see text]–74 Hz. These large phase anomalies are probably caused by polarization of the magnetite-solution interfaces. With the redox-active ion [Formula: see text], frequency of peak phase response decreased progressively from [Formula: see text] to [Formula: see text] as effluent pH increased from four to seven, corresponding to progressive adsorption of [Formula: see text] to the magnetite surface. The latter frequency (3 Hz) corresponds approximately with those of phase anomalies detected in field surveys reported elsewhere. We conclude that pH sensitivity arises from redox reactions between [Formula: see text] and magnetite surfaces, with transfer of electrical charge through the bulk mineral, as reported in other laboratory investigations. Our results confirm that SIP measurements are sensitive to redox reactions involving charge transfers between adsorbed ions and semiconductive minerals. Phase anomalies seen in field surveys of groundwater contamination and biostimulation may therefore be indicative of iron-reducing conditions, when semiconductive iron minerals such as magnetite are present.