Добірка наукової літератури з теми "Na-S Batteries"

Many problems associated with Li–S and Na–S batteries essentially root in the generation of their soluble polysulfide intermediates. While conventional wisdom mainly focuses on trapping polysulfides at the cathode using various functional materials, few strategies are available at present to fully resolve or circumvent this long-standing issue. In this study, we propose the concept of sulfur-equivalent cathode materials, and demonstrate the great potential of amorphous MoS3 as such a material for room-temperature Li–S and Na–S batteries. In Li–S batteries, MoS3 exhibits sulfur-like behavior with large reversible specific capacity, excellent cycle life, and the possibility to achieve high areal capacity. Most remarkably, it is also fully cyclable in the carbonate electrolyte under a relatively high temperature of 55 °C. MoS3 can also be used as the cathode material of even more challenging Na–S batteries to enable decent capacity and good cycle life. Operando X-ray absorption spectroscopy (XAS) experiments are carried out to track the structural evolution of MoS3. It largely preserves its chain-like structure during repetitive battery cycling without generating any free polysulfide intermediates.

Imaging techniques are increasingly used to study Li-ion batteries and, in particular, post-Li-ion batteries such as Li–S batteries, Na-ion batteries, Na–air batteries and all-solid-state batteries. Herein, we review recent advances in the field made through the use of these techniques.

The use of chalcogenide elements, such as sulfur (S) and selenium (Se), as cathode materials in rechargeable lithium (Li) and sodium (Na) batteries has been extensively investigated. Similar to Li and Na systems, rechargeable potassium–sulfur (K–S) and potassium–selenium (K–Se) batteries have recently attracted substantial interest because of the abundance of K and low associated costs. However, K–S and K–Se battery technologies are in their infancy because K possesses overactive chemical properties compared to Li and Na and the electrochemical mechanisms of such batteries are not fully understood. This paper summarizes current research trends and challenges with regard to K–S and K–Se batteries and reviews the associated fundamental science, key technological developments, and scientific challenges to evaluate the potential use of these batteries and finally determine effective pathways for their practical development.

Rechargeable batteries are a major element in the transition to renewable energie systems, but the current lithium-ion battery technology may face limitations in the future concerning the availability of raw materials and socio-economic insecurities. Sodium–sulfur (Na–S) batteries are a promising alternative energy storage device for small- to large-scale applications driven by more favorable environmental and economic perspectives. However, scientific and technological problems are still hindering a commercial breakthrough of these batteries. This review discusses strategies to remedy some of the current drawbacks such as the polysulfide shuttle effect, catastrophic volume expansion, Na dendrite growth, and slow reaction kinetics by nanostructuring both the sulfur cathode and the Na anode. Moreover, a survey of recent patents on room temperature (RT) Na–S batteries revealed that nanostructured sulfur and sodium electrodes are still in the minority, which suggests that much investigation and innovation is needed until RT Na–S batteries can be commercialized.

The purpose of this diploma thesis is to describe the impact of compaction pressure on the electrochemical parameters of lithium-sulfur batteries. Theoretical part of this thesis contains briefly described terminology and general issues of batteries and their division. Every kind of battery is provided with a closer description of a specific battery type. A separate chapter is dedicated to lithium cells, mainly lithium-ion batteries. Considering various composition of lithium-ion batteries, this chapter deeply analyzes mostly used active materials of electrodes, used electrolytes and separators. Considering that the electrochemical principle of Li-S and Li-O batteries is different to Li-ion batteries, these accumulators of new generation are included in individual subhead. In the experimental part of this thesis are described methods used to measure electrochemical parameters of Li-S batteries. Next chapter contains description of preparing individual electrodes and their composition. Rest of the experimental part of my thesis is dedicated to the description of individual experiments and achieved results.

The presented master´s thesis deals with lead-acid batteries and methods of their charging. First part shortly describes the problems of lead-acid batteries. There are introduced common principles, type of construction and requirements, that should be complied with lead-acid batteries. Following part discusses the basic characteristics of charging. There is given a detailed description of current pulse charging method, on which is also mainly focused this master´s thesis. For this charging method, several basic experiments were done in order to verify functionality of the measuring device, software, the tested cells and primarily to verify charging modes. The goal of this thesis is to find out suitable mode of pulse charging, which would be fast as well as tested cells-friendly. The conclusion of this master´s thesis contains a resume of acquired theoretical knowledge and an evaluation of measured results, on which was the appropriate charging mode proposed.

Lithium/sodium-sulfur (Li/Na-S) batteries hold practical promise for next-generation batteries because of high energy density and low cost. Development is impeded at present however because of unsatisfied discharge capacity and stability in long cycling. Advanced materials can serve as sulfur host materials to improve the capacities and stability of the lithium/sodium-sulfur batteries. More importantly, they provide suitable models with which to connect and test experimental results with theoretical predictions. This is crucial to develop insight into the relationship between electrochemical behavior of sulfur and the structural properties of sulfur host materials. This thesis explores sulfur and its intermediates adsorption/redox conversion mechanisms and investigate crucial structural-property relationships of the advanced nanomaterials as sulfur host materials in high-performance lithium/sodium-sulfur batteries. First, A unique three-dimensional hybrid of nickel sulfide and carbon hollow spheres was synthesized as a sulfur host. The uniformly distributed nickel sulfide can greatly promote adsorption capability towards polysulfides. Meanwhile, the hollow carbon spheres increase sulfur loading as well as the overall conductivity of the sulfur host. Utilized in an electrode, this 3D hybrid sulfur host achieved a capacity of 695 mA h g-1 after 300 cycles at 0.5 C and a low capacity decay of 0.013% per cycle. Second, a two-dimensional (2D) MoN-VN heterostructure is investigated as a model sulfur host. The 2D heterostructure can regulate polysulfides and improve sulfur utilization efficiency. This resulted in superior rating and cycling performance. More importantly, incorporation of V in the heterostructure can effectively tailor the electronic structure of MoN. This leads to enhanced polysulfides adsorption. Last, a two-dimensional (2D) metal-framework (MOF) is investigated as a model sulfur host for Na-S batteries. The MOF can enhance polysulfides adsorption and conversion kinetics. This resulted in superior rating and cycling performance. Through a combination of advanced experimental characterization techniques and theoretical computations based on the 2D nanomaterials, an in-depth understanding of sulfur redox and the structure-properties relationships in metal-sulfur batteries have been obtained.
Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering & Advanced Materials, 2019

In this thesis, we have attempted to understand the working principle of Li(Na)-S(Se) battery and following such understandings we have attempted towards the design of various S(Se)- cathode materials for the alkali based chalcogen batteries. In the final chapter, we have focussed on the development of anode materials for full Li-ion cell. The summary of the various chapters is as follows. Chapter 2 discusses about NaY-xS-PAni exhibiting remarkable electrochemical performance as a cost-effective sulfur cathode for rechargeable Li-S batteries. The superior electrochemical stability and performance of the NaY-xS-PAni is directly correlated to the novel NaY electrode structure in combination with the host polarity and ionic conductivity. The zeolite provides an optimum geometrical and chemical environment for precise confinement of the sulfur while the polyaniline coating provides electron conduction pathway along with extra polysulfide confinements. This cathode material exhibits very stable cycling for more than 200 cycles with relatively low specific capacity and modest rate capability. To develop a material for obtaining high specific capacity value we moved to carbon based host and the details are covered in chapter 3 and 4. To summarize Chapter 3, we have successfully extended the pressure induced capillary filling method for confinement of sulfur and selenium in the interior core of the MWCNTs. This method results in ultra-high loading yields of the chalcogens inside the MWCNTs. The ensuing composites S-CNT have been convincingly demonstrated as prospective cathodes in Li-S rechargeable batteries exhibiting very high specific capacities ~ 1000 mAh g-1 at C/10 current rates. The novelity of this host has been established by extending the work in encapsulating Se with the similar protocol and studying its electrochemical activity. The high efficiency of the Li-S/Se electrochemical reaction observed here is directly attributed to the efficacy of the encapsulation protocol of S/Se inside the CNTs. The polyselenides/polysulfides are completely confined within the precincts of the CNT cavity leading to an exceptionally stable battery performance at widely varying current densities. With the success of this encapsulation technique for the carbon based host, we developed another interconnected mesoporous microporous carbon host for sulfur encapsulation the details of which constitute the next chapter. In chapter 4, we have discussed here a novel S-cathode where the sulfur confining hierarchical carbon host synthesized using a sacrificial template can be very effectively employed for in Li-S rechargeable battery. The hierarchical mesoporous-microporous architecture comprising of both mesopores and micropores provide an optimal potential landscape which in turn traps high amounts of sulfur as well as polysulfides formed during successive charge-discharge cycles. The uniqueness of the carbon matrix translates to exceptionally stable reversible cycling and rate capability for Li. Such promising result with Li-S battery compelled us to check the performance with Na anode. This led to the development of intermediate temperature Na-S battery with JNC-S as the prospective cathode. It is envisaged that such materials design will be very promising in general for battery chemists especially for higher valent metal-sulfur systems (e.g. magnesium, aluminum). The host discussed here will be ideally suitable for introduction of dopants such as nitrogen, boron, thus enhancing it’s versatility as a heterodoped mesoporous-microporous host for varied applications. In all the preceding chapters, the focus was to encapsulate sulfur in some host structures. Chapter 5 deals with an alternative configuration for the Li-S battery that uses an oxide based interlayer to restrict the polysulfides. From the study discussed here, it can be concluded that NiOH-np/NiO-np can act as an efficient interlayer material for superior anode protection. The interlayer provides an anchor to hold back the polysulfides primarily on the cathode side by forming intermediates such as NiS3(OH) and NiS4(OH). Although, the specific capacity is less compared to the theoretically estimated value for S-cathode, the high cyclability coupled with extremely good rate capability performance makes this a very promising configuration of Li-S cell assembly for practical applications and deployment. The success of this strategy is expected to decrease the need for design of sophisticated S-scaffolds and lead to simpler Li-S rechargeable batteries. After an extensive discussion on development of cathodes for alkali based chalcogen batteries, we shifted gears and tried our hands in developing some eco-friendly anode materials. The details of graphitic carbonitride as an anode material for Li-ion cell has been discussed in chapter 6. To conclude, we have discussed here in detail the unique layered structure of the as-synthesized gCN and its impact on the intrinsic charge transport properties. Both factors eventually determine their electrochemical performance. The gCN discussed here is obtained using a very simple synthesis protocol in large yields from a very cheap organic precursor. The work highlights again the important role of chemical composition and structure on the functionality of the intercalation host. These have a strong bearing on the electronic charge distribution in the host and its eventual interaction with the intercalating ions. Compared to several non-trivial layered carbonaceous structures, the gCN interestingly displays 3-D ion transport. Additionally, it also sustains facile electron transport (2-D) despite the low concentration of carbon. In spite of the modest specific capacities as observed in case of the half cells, the gCN when assembled with (high) voltage cathodes in full Li-ion cells, the performance is quite encouraging. To the best of our knowledge this is for the first time that graphitic carbon nitrides have been demonstrated as an anode in full Li-ion cells. The potential of majority of the reported high surface area and high capacity complex carbonaceous structures in Li-ion cells are inconclusive. This is mainly due to the fact that the percentage of reports on full Li-ion cell performance is very rare. The full cell analysis of the gCN discussed here conclusively rules out the necessity of the requirement of high specific capacity materials in practical/commercial full cells. We envisage that the work discussed here will pave the way for synthesis of many such electrode materials from renewable resources resulting in the development of green and sustainable batteries. Overall we have been able to address some of the potential problems of Li-S and Li-ion battery systems. There is further scope of betterment with extensive study and this work opens the scope for it in future.

The thesis entitled “Design of Electroactive Materials and Mechanistic Investigations of Metal (Li, Na, Mg)-Sulfur Batteries’’ deliberates on some of the important issues impeding the progress of metal sulfur battery (Li/S, Na/S, Mg/S) and discusses possible materials design as well as alternative cell configuration strategies to alleviate them. The major factor hindering the practical applications of metal sulfur battery is the dissolution of intermediate polysulfides into the ether-based electrolyte during the battery cycling. The present thesis discusses in detail the usage of conductive additive in sulfur cathode as one of the important strategies for the confinement of intermediate polysulfides at the S-cathode. This chemical design strategy is highly effective for both Na/S and Li/S batteries. Apart from the polysulfides dissolution, volume expansion and safety concerns are the other challenges in practical applications of metal sulfur battery. To alleviate such issues, an alternative cell configuration has been proposed. Instead of the sulfur element cathode, fully expanded state of polysulfides viz. lithium sulfide (final discharge product of S8  Li2S) is used as the cathode and lithium metal is replaced by lithiated anatase TiO2. The various stages of redox reaction occurring in the metal-sulfur battery have been extensively investigated using various operando and ex-situ spectroscopic techniques. Apart from the design strategy of the S-cathode, the present thesis also discusses the major challenges associated with electrolyte in bivalent metal sulfur battery system viz. the Mg/S system. Majority of the literature reports the Mg/S battery performance with TEGDME and THF solvent-based electrolyte. However, the persistent concern regarding the lower current density and poor cyclability of TEGDME and higher volatility of THF put Mg/S on the backfoot for practical applications. The present thesis discusses a new class of electrolyte using 1,3-Dioxalane (DOL)/1,2-Dimethoxyethane (DME) binary solvent in Mg/S battery. Like Li/S and Na/S battery system, various intermediate polysulfides formation take place in the Mg/S system as well. The present thesis discusses in detail the polysulfide confinement mechanism in the Mg/S system using operando and ex-situ spectroscopic techniques.
DST Nano Mission

Energy storage has recently attracted significant interest as an enabling technology for integrating stochastic, variable renewable power into the electric grid. To meet the renewable portfolio standards targets imposed by 29 U.S. states and the District of Columbia, electricity production from wind technology has increased significantly. At the same time, wind turbines, like many renewables, produce power in a manner that is stochastic, variable, and non-dispatchable. These attributes introduce challenges to generation scheduling and the provision of ancillary services. To study the impacts of the stochastic variability of wind on regional grid operation and the role that energy storage could play to mitigate these impacts, Pacific Northwest National Laboratory (PNNL) has developed a series of linked, complex techno-economic-environmental models to address two key questions: A) What are the future expanded balancing requirements necessary to accommodate enhanced wind turbine capacity, so as to meet the renewable portfolio standards in 2020? Specific analyses are conducted for the four North American Electric Reliability Corporation (NERC) western subregions. B) What are the most cost-effective technological solutions for providing either fast ramping generation or energy storage to serve these balancing requirements? PNNL applied a stochastic approach to assess the future, expanded balancing requirements for the four western subregions with high wind penetration in 2020. The estimated balancing requirements are quantified for four subregions: Arizona-New Mexico-Southern Nevada (AZ-NM-SNV), California-Mexico (CA-MX), Northwest Power Pool (NWPP), and Rocky Mountain Power Pool (RMPP). Model results indicate that the new balancing requirements will span a spectrum of frequencies, from minute-to-minute variability (intra-hour balancing) to those indicating cycles over several hours (inter-hour balancing). The sharp ramp rates in the intra-hour balancing are of significant concern to grid operators. Consequently, this study focuses on analyzing the intra-hour balancing needs. A detailed, life-cycle cost (LCC) modeling effort was used to assess the cost competitiveness of different technologies to address the future intra-hour balancing requirements. Technological solutions considered include combustion turbines, sodium sulfur (NaS) batteries, lithium ion (Li-ion) batteries, pumped-hydro energy storage (PHES), compressed air energy storage (CAES), flywheels, redox flow batteries, and demand response (DR). Hybrid concepts were also evaluated. For each technology, distinct power and energy capacity requirements are estimated. LCC results for the sole application of intra-hour balancing indicate that the most cost competitive technologies include Na-S batteries, flywheels, and Li-ion assuming future cost reductions. Demand response using smart charging strategies was found to also be cost-competitive with natural gas combustion turbines. This finding is consistent among the four subregions and is generally applicable to other regions.