Academic literature on the topic 'Zinc metal battery'

The hierarchical honeycomb-like transition-metal/nitrogen co-doped carbon materials were fabricated, and they acted as highly efficient electrocatalysts for the cathode of a zinc–air battery and the anode of a zinc-ion battery.

Many efforts have been devoted to the improvement of metal-air batteries. Aluminum (Al) is the most abundant metal in the Earth’s crust and has high electrochemical potential. Therefore, the aluminum-air battery is one of the most attractive metal-air batteries. To overcome some disadvantages of the aluminum-air battery, some alloys of aluminum and several metals have been proposed. In this study, the performance improvement of the aluminum-air battery by doping zinc (Zn) to the aluminum anode was investigated. Zinc was doped to aluminum by a simple process. The difference in the characteristics of Zn-doped Al due to different heating temperature during the doping process was also investigated. The maximum power density of the battery was 2.5 mW/cm2.

Integrating a photoelectrode into a zinc-air battery is a promising approach to reducing the overpotential required for charging a metal-air battery by using solar energy. In this work, a photo-fuel cell employing a Nb2O5/CdS photoanode and a Zn foil as a counter-electrode worked as a photoelectrochemical battery that saves up to 1.4 V for battery charging. This is the first time a Nb2O5-based photoelectrode is reported as a photoanode in a metal-air battery, and the achieved gain is one of the top results reported so far. Furthermore, the cell consumed an organic fuel, supporting the idea of using biomass wastes as a power source for sunlight-assisted charging of metal-air batteries. Thus, this device provides additional environmental benefits and contributes to technologies integrating solar energy conversion and storage.

A rechargeable cement-based battery was developed, with an average energy density of 7 Wh/m2 (or 0.8 Wh/L) during six charge/discharge cycles. Iron (Fe) and zinc (Zn) were selected as anodes, and nickel-based (Ni) oxides as cathodes. The conductivity of cement-based electrolytes was modified by adding short carbon fibers (CF). The cement-based electrodes were produced by two methods: powder-mixing and metal-coating. Different combinations of cells were tested. The results showed that the best performance of the rechargeable battery was the Ni–Fe battery, produced by the metal-coating method.

Zinc–air batteries are promising candidates as stationary power sources because of their high specific energy density, high volumetric energy density, environmental friendliness, and low cost. The oxygen-related reactions at the air electrode are kinetically slow; thus, the air electrode integrated with an oxygen electrocatalyst is the most critical component, and inevitably determines the performance of a Zn–air battery. The aim of this paper was to document progress in researching bifunctional catalysts for Zn–air batteries. The catalysts are divided into several categories: noble metal, metal nanoparticle (single and bimetallic), multicomponent nanoparticle, metal chalcogenide, metal oxide, layered double hydroxide, and non-metal materials. Finally, the battery performance is compared and discussed.

Zinc-air battery is a promising battery system as it possesses high theoretical energy density and is cost-effective3. The theoretical energy density of a Zinc-air battery is 1086 Wh kg-1, which is five times greater than that of lithium-ion batteries2. Moreover, zinc metal is one of the most abundant metals in the earth’s crust and is inexpensive. Rechargeable metal-air batteries operate based on two fundamental electrochemical reactions as Oxygen Reduction Reaction (ORR) during discharge and Oxygen Evolution Reaction (OER) during recharge processes, respectively3. Electrocatalytic activity of the bifunctional electrocatalyst towards these two oxygen reactions will decide the performance of the battery1. Recent advancements in catalyst development are the fabrication of rechargeable air electrodes using a single active material that is capable of bifunctionally catalyzing ORR and OER3. The development of bifunctional catalysts with high activity is necessary for rechargeable metal-air batteries, such as zinc-air batteries3. In this work, a perovskite-type LaFeO3 material was synthesized using a citric acid-assisted sol-gel method and is investigated as bifunctional oxygen electrocatalyst for electrically rechargeable zinc-air batteries. Structural studies using X-ray diffraction revealed the formation of phase pure LaFeO3 in space group Pbnm. This catalyst displayed considerable bifunctional catalytic activity for both oxygen reduction (0.74 V vs. RHE) and oxygen evolution reactions (0.40 V vs. RHE at 10 mA cm-2) in 1 M KOH electrolyte. Electrically rechargeable zinc-air batteries assembled using LaFeO3 as the oxygen electrocatalyst deliver a specific capacity of 936.38 mAh g( Zn) -1 after the 1st discharge. Further details will be discussed in the poster. Financial support from Department of Science and Technology, Govt. of India under research grant number DST/TMD/MECSP/2K17/20 is gratefully acknowledged. References: [01] Y. Li, M. Gong, et. al., Nature communications, 4, (2013), 1-7 [02] P. Gu, M. Zheng, et. al., Journal of Material Chemistry, (2017), 1-17 [03] D. U. Lee, P. Xu, et. al., Journal of Material Chemistry, 4, (2016), 7107-7134

ABSTRACTFlexible zinc-air batteries were fabricated using an inexpensive screen-printing technique. The anode and cathode current collectors were printed using commercial nano-silver conductive ink on a polyethylene terephthalate (PET) substrate and a polypropylene (PP) membrane, respectively. Air cathodes made of blended carbon black with inexpensive metal oxides including manganese oxide (MnO2) and cerium oxide (CeO2), were studied. The presence of the metal oxides in the air cathodes enhanced the oxygen reduction reaction which is the most important cathodic reaction in zinc-air batteries. The battery with 20 %wt CeO2showed the highest performance and provided an open-circuit voltage of 1.6 V and 5 – 240 mA.cm-2ohmic loss zone. The discharge potential of this battery at the current density of 5 mA.cm-2was nearly 0.25 V higher than that of the battery without metal oxides. Finally, the battery was tested for its flexibility by bending it so that its length decreased from 2.5 to 1 cm. The results showed that the bending did not affect characteristics on potential voltage and discharging time of the batteries fabricated.

Aqueous zinc-ion batteries (ZIBs) as a new battery technology have received great attention due to the high energy and power density, low cost, high safety and environmental friendliness. However, their practical deployment has been restricted by some serious issues such as corrosion of zinc metal anode in aqueous electrolyte, undesired growth of zinc dendrites, and hydrogen evolution from the water splitting. Therefore, tremendous efforts have been devoted to mitigate these issues and significant progresses have been achieved. In this paper, we review some key recent progresses of aqueous ZIBs, focusing on materials engineering strategies that are able to address the major challenges. Moreover, we provide rational perspectives on the future development of ZIBs.

Zinc-air battery technology is gaining recognition as a promising energy storage device to be used in portable electronics and electric vehicles. Despite possessing high theoretical energy density, environmental and operational safety, and easy accessibility of zinc reservoirs, the successful commercialization of zinc-air batteries suffers due to the poor oxygen electrocatalysis kinetics at the air cathode. The kinetically inept oxygen reduction and oxygen evolution reactions at the cathode lead to a large overpotential barrier and poor charge-discharge cyclic performance of the rechargeable zinc-air battery. This work demonstrates designing a multi-principal metal bifunctional electrocatalyst that is directly deposited on conductive, porous, and flexible substrates to eliminate the necessity of polymeric binders. The flexible bifunctional oxygen electrocatalyst used for the cathode of solid-state ZAB is assembled with gel polymer electrolyte and zinc anode giving excellent charge-discharge cyclic stability and constant discharge voltage (close to 1.65 V). These multi-principal metal electrocatalysts constituting quasi-equimolar concentration, provide numerous combinations of surface functionality, multiple adsorption sites, and electronic environments thus enabling better optimization of the catalytic performance.

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Lead (Pb) is a metal that is very stable in soil and highly toxic to humans and animals. Exposure to Pb occurs via inhalation of particles from industry and soil, as well as household dust, water, and contaminated food. A greenhouse experiment was carried out to evaluate Pb contents and allocation in vegetable crops grown in soil contaminated by battery recycling wastes. The experiment was conducted in a randomized block design factorial 8x4, with four replicates. Four parts (root, stem, leaf and edible parts) of eight plant species (tomato, sweet pepper, beet, carrot, cabbage, green collards, eggplant, and okra) were studied. The results showed that carrot, green collards, beet, and okra were the most Pb tolerant species, while the others were very Pb-sensitive, since they did not complete their cycle. The decreasing order for Pb concentration in the root of crops was: carrot > okra > tomato and eggplant > sweet pepper > kale > cabbage. Taking into account Pb allocation in plants, the order was: root > stems > leaves > edible parts. Pb allocated in the edible parts may exceed o tolerable limit.
Os metais pesados podem ser deletérios ou essenciais aos seres vivos. Entre os deletérios, o Pb tem destaque por ser extremamente tóxico para humanos. A intensificação das atividades industriais e agrícolas, devido ao aumento populacional nos últimos anos, tem contribuído à poluição dos solos agrícolas com Pb, podendo torná-los inadequados à produção de alimentos saudáveis. Com relação aos metais essenciais, o Zn tem causado preocupação, tendo em vista que a escassez deste elemento nos alimentos tem sido um dos maiores responsáveis pela desnutrição em grande parte da população do planeta. Para reduzir os efeitos da desnutrição, pesquisas estão sendo desenvolvidas através da estratégia de biofortificação de partes comestíveis de vegetais, visando a produção de alimentos saudáveis e com qualidade, que apresentem menor teor de contaminantes inorgânicos e maior concentração de micronutrientes essenciais. No entanto, no Brasil ainda são poucas as pesquisas que visam avaliar teores de metais deletérios e micronutrientes em alimentos vegetais e, nesse contexto, no presente trabalho foram desenvolvidos quatro experimentos tendo como objetivos avaliar: 1) teores e alocação de Pb por hortaliças cultivadas em solo contaminado com resíduos de reciclagem de baterias; 2) o efeito do Pb na concentração de nutrientes em olerícolas, bem como o potencial de transferência desse elemento de um solo contaminado por baterias automotivas para as partes comestíveis das hortaliças; 3) o efeito do Pb sobre a absorção de micronutrientes, distribuição do Pb entre as frações de um Espodossolo e a relação dessas frações com a disponibilidade do metal para hortaliças e 4) a transferência de Zn do solo para partes comestíveis de cenoura, couve manteiga e quiabeiro cultivadas em latossolo tratado com doses de zinco. Os resultados desses experimentos demonstraram que o teor de Pb determinado nas espécies obedeceu a ordem: cenoura > quiabo > tomate > berinjela > pimentão > couve-manteiga > repolho > beterraba, com alocação preferencialmente na raiz, seguida por caule, folha e parte comestível. A concentração de Pb transferida à parte comestível da cenoura foi superior ao limite de tolerância máximo estipulado na legislação. O Pb promoveu desbalanço nutricional nas plantas, sendo ainda observado que os macronutrientes concentraram-se, preferencialmente, nas folhas, enquanto que os micronutrientes foram alocados nas raízes. Plantas de couve manteiga apresentaram maior potencial para concentrar Zn em sua parte comestível, comparativamente à cenoura e quiabeiro, sendo indicadas para utilização em programas de biofortificação.

The ever-increasing energy consumption and the environmental issues from the excessive rely on fossil fuels have triggered intensive research on the next generation power sources. Metal-air batteries, as one of the most promising technologies emerged, have attracted enormous attention due to its low cost, environmental benignity and high energy density. Among all types of metal-air batteries, Zn-air batteries in particular have tremendous potential for use as alternative energy storage primarily by the low-cost, abundance, low equilibrium potential, environmental benignity, a flat discharge voltage and a longer shell life. However, there are still issues in pertinent to the anode, electrolyte and cathode that remain to be overcome. In particular, the electrocatalyst at the cathode of a metal-air battery which catalyzes the electrochemistry reactions during charge and discharge of the cell plays the most crucial role for the successful commercialization of the metal-air technology. A series of studies from the carbon nanofibres to spinel cobalt oxide and perovskite lanthanum nickelate was conducted to explore the ORR/OER catalytic properties of those materials which lead to further investigations of the non-precious metal oxide/carbon hybrids as bifunctional catalysts. Introducing ORR active species such as nitrogen, sulfur, boron and phosphorus into high surface area carbon has been an effective strategy to fabricate high catalytic activity ORR electrocatalyst. Carbon nanofibre is an abundant, low cost and conductive material that has tremendous potential as ORR catalyst, especially via KOH activation and nitrogen-doping post-treatments. These two post-treatment methods serve as simplistic methodologies to enhance the carbon surface area and ORR catalytic activity of the pristine carbon nanofibres, respectively. The activated and nitrogen-doped carbon nanofibres demonstrated 26% of improved half-wave potential and 17% of increased limiting current density as a comparison to the pristine carbon nanofibre via RDE testing in alkaline electrolyte. To realize the catalytic activity of activated and nitrogen-doped carbon nanofibres in a more practical condition, they are further evaluated in Zn-air batteries. Polarization curves retrieved from Zn-air cell testing showed 75% higher voltage obtained by activated and nitrogen-doped carbon nanofibres than pristine carbon nanofibres at 70mAcm-2 current density. Structured oxides such as spinels and perovskites have been widely reported as ORR and OER catalyst in metal-air batteries. It is widely known that the properties of nanostructures are closely pertinent to their morphologies. The initial performance and durability of cubic Co3O4 synthesized from Feng et al and LaNiO3 from modified sol-gel method are tested in RDE system. After the durability testing, the ORR onset potential and limiting current density of cubic Co3O4 has decreased by 50% and 25%, respectively, whereas the OER limiting current density dropped significantly from ~15mAcm2 to almost zero current density. LaNiO3 with different particle sizes synthesized from modified sol-gel method was prepared and evaluated in RDE system. A particle size related performance can be clearly seen from the RDE results. The ORR limiting current of the lanthanum nickelate with smaller particle size (LNO-1) is higher than that of lanthanum nickelate with larger particle size (LNO-0) by 40% and the OER limiting current of LNO-1 is almost tripled that of LNO-0. With the previous experience on carbon material and structured oxides, two hybrid bifunctional catalysts were prepared and their performance was evaluated. cCo3O4/ExNG was made by physically mixing of cCo3O4 with ExNG with 1to 1 ratio. The hybrid showed enhanced bifunctional catalytic activities compared to each of its individual performance. Based on the voltammetry results, a significant positive shift (+0.16V) in ORR half-wave potential and tripled limiting current were observed in the case of the hybrid compared to the pure cobalt oxide. By combing cCo3O4 and ExNG, the OER limiting current of the hybrid exceeds that of cCo3O4 by ca. 33% and four-fold that of the ExNG. The kinetic current density at -0.4V for cCo3O4/ExNG is 15.9 mAcm-2 which is roughly 4 times the kinetic current density of the ExNG (3.8 mAcm-2) and over 10 times greater than that of cCo3O4 (1.1 mAcm-2). Electrochemical impedance spectroscopy showed that the charge transfer resistance of the hybrid is ca. one third of cCo3O4 and roughly only one half of ExNG which suggests a more efficient electrocatalysis of the hybrid on the air electrode than the other two. Mixing structured oxides with carbon material provides a simple method of fabricating bifunctional catalysts, however the interactions between those two materials are quite limited. In-situ synthesis of cCo3O4/MWCNT hybrid by chemically attaching cCo3O4to the acid-functionalized MWCNT is able to provide strong interactions between its components. Through RDE testing, the ORR activity of cCo3O4/MWCNT outperformed its individual component showing the highest onset potential (-0.15V) and current density (-2.91 mAcm-2 at -0.4V) with ~4 electron transfer pathway. Moreover, the MWCNT and cCo3O4 suffered from significant OER degradation after cycling (92% and 94%, respectively) whereas the hybrid material demonstrated an outstanding stability with only 15% of performance decrease, which is also far more superior to the physical mixture (30% higher current density). Among all the catalyst studied, cCo3O4/MWCNT has the highest performance and durability. The excellent performance of the hybrid warrants further in-depth research of non-precious metal oxide/carbon hybrids and the information presented in this thesis will create afoundation for future investigation towards high performance and durability bifunctional electrocatalysts for metal-air battery applications.

碩士
國立聯合大學
能源工程學系碩士班
106
In this study, composite technology was applied to the development of metal bipolar plates for vanadium redox flow battery (VRFB) and zinc electrode for zinc-air battery. The performance these two batteries were also evaluated. These batteries had great potential for energy storage application. Composite carbon material has good electric conductivity, corrosion resistance, and low cost. They are widely used in batteries. Replacing the carbon bipolar plate of VRFB battery to a metal bipolar plate, not only greatly reduces the internal resistance of the battery, but also increases the power density of the battery. The use of metal composites needs to overcome the problem of metal corrosion. This study developed a conductive anti-corrosion layer for protecting the surface of metal bipolar plates. The paste ratio, process conditions, and process methods of different carbon materials and binders were studied to improve the coating of conductive anti-corrosion layer. The composite carbon material can also be applied to a zinc electrode a zinc-air battery. The zinc electrode may produce dendritic crystals during charging and cause damage to the battery. In this study, different proportions of 5-20% carbon powder was mixed with zinc powder to form the zinc electrode. These electrodes were tested by using simulated charging and discharging to evaluate the effectiveness of this zinc electrode.

碩士
國立清華大學
材料科學工程學系
104
With the rapidly increasing development of global technological civilization, energy demand is increasing, too. Due to energy production system and energy storage system developing rapidly; the damage to the environment has become more and more critical. How to take account the two aspects of energy demand and environmental protection will be the focus of future energy-related technology. In the process of developing new energy technologies, the field of electric vehicles is paid the considerable attention to. Because of the insufficiency of the battery’s efficiency on the electric vehicles and the highly price on the batteries, it is needed to develop a more suitable technology for the electric vehicle energy storage. And Zinc-air battery is quite potential in this area. According to many related literatures about air battery, the researchers are devoted to improve electrical properties of charging and discharging, energy and power density and cycle life. As to the part of the metal electrode, the researchers changed the morphology of the electrode , the materials of the electrode, adding alloying elements, and the surface modification, etc. In view of the part of alkaline aqueous electrolyte, many literatures investigated the influence of additives for electrode corrosion, and improved the performance of batteries effectively. It is rare to find the literatures which mentioned both about electrode and an electrolyte additive. As a result, it will discuss for both in this study. In this study, the metal electrode with template method was produced. First of all, PU polyurethane porous foam was used as the template. And then it employed the method of activation in Palladium membrane, non-electroplated and electroplated methods of Nickel sequentially. Next, a three-dimensional electrode with stable structure was produced, and this was a unique novelty. And then the charging and discharging properties of the electrode in Zinc-air batteries was improved by plating Tin on surface modification and doing Zinc pre-deposition in this study. Concerning the electrolyte, it used Tin sheet as electrode firstly and was measured by CV curves and Tafel polarization curves to investigate the influence of additives for electrode corrosion. And according to the result of the experiment, EDTA and Tween 20 was selected as the additives for battery testing. In addition to battery testing, the material analysis was made for each step in the electrode making process, including SEM analysis for surface topography and coating thickness, EDS analysis for category and ratio of element, and XRD analysis for metal crystalline, crystal structure and element types in this study. It also discussed both the nature of the materials for the electrode, and the characteristics of electrochemical charging and discharging .

碩士
國立中正大學
化學工程研究所
107
Zinc air battery (ZAB) is one of the most important research fields in energy storage application. The study of ZAB mainly development focuses on the catalysts with high efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) so that the battery is capable of conducting with charging and discharging processes. In this study, carbon-nanotube (CNT) -grafted and Co3O4-doped porous carbon was prepared by the carbonization of the synthesized zeolitic imidazolate framework (ZIF-67/ZIF-8) compound followed by an oxidation treatment. The novel catalyst demonstrated excellent ORR and OER because of the Co3O4 nanoparticles and nitrogen-doped in the carbon framwork (NC). In addition, the carbon nanotube grafted on the framework provided a good electrical conductivity while the carbon framework matrix provided a porous skeleton which is beneficial for the mass transfer of electrolyte. In the ORR study, the novel catalyst, CNT-Co3O4/NC, showed a half-wave potential of -0.124 V at 0.1 M KOH (Pt/carbon: -0.152 V) while the limited current density is 4.84 mA/cm2 (Pt/ carbon: 4.9 mA/cm2). In terms of OER performance, the potential is 0.819 V at current density of 10 mA/cm2 (Ir/carbon: 0.771 V). In the ZAB study, with CNT-Co3O4/NC catalyst, a specific capacitance of 814 mAh/g (1.19 V at 50 mA/cm2) was obtained, which is very close to the theoretical capacitance (820 mAh/g) and maximum power density was 267 mW/cm2 (0.746 V at 385 mA/cm2) while 255 mW/cm2 (0.711 V at 360 mA/cm2) was obtained using Pt/carbon catalyst. We believe that the novel CNT-Co3O4/NC can be used as an excellent catalyst in the zinc-air battery.

碩士
國立中正大學
化學工程研究所
105
The first part of the study is to investigate the performance of the manganese dioxide nanowires used in the catalyst layer for zinc air battery. Carbon nanocapsule and mesoporous carbon were employed as the substrates for dioxide manganese nanowires. The properties of the CNC/MnO2 N.W. and MPC/MnO2 N.W. were analyzed with scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). The results confirmed that the cryptomelane-type MnO2 was formed. The CNC/MnO2 N.W. had the highest number of electrons transferred which is calculated as 3.94 by rotating ring-disk electrode test (RRDE). The discharge voltage of 1.1 V and the specific capacity of 819 mA/g were achieved at 50 mA/cm2. The maximum power density is 131 mW/cm2 at 179 mA/cm2. The discharge potential retention is 89.2 % after 300 cycles test. Polyimide carbon fibers containing metal catalyst were prepared by electrospinning technology. The materials properties of the CoCl2/PI-CNF and Co(acac)2/PI-CNF were analyzed with scanning electron microscope (SEM), X-ray diffraction (XRD). The results confirmed that cubic β-phase pure cobalt metal was formed. The CoCl2/PI-CNF had the highest number of electrons transferred which is calculated as 3.83 by rotating ring-disk electrode test (RRDE). During full battery test, the discharge voltage of CoCl2/PI-CNF is about 1.1 V and the specific capacity is 799 mA/g at 50 mA/cm2. The maximum power density is 112 mW/cm2 at 158 mA/cm2. The discharge potential retention of battery is 91 % after 300 cycling test. Current collectors were studied using a rariety of metal materials with different mesh numbers. The battery performance was investigated as function of the different mesh size of the stainless steel mesh. According the results of full battery, the power density of 119 mW/cm2 at 169 mA/cm2, can be achieved by the stainless steel with mesh number of 500. Keywords：Manganese dioxide, Nano, Electrospinning, Current collector

碩士
國立中正大學
化學工程研究所
103
Carbon nanocapsele (CNC) is employed as substrates for petal-like MnO2 nanostructures on surface (CNC@MnO2) by reflux synthesis. The characterization of the materials were conducted with scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Raman analysis. The results confirm that the birnessite-type MnO2 was formed. The number of electrons transferred is calculated as 3.94 by rotating ring-disk electrode (RRDE). The discharge voltage of 1.1 V and specific capacity of 804 mAhg-1 are obtained at 50 mAcm-2. A maximum power density is 138 mWcm-2 at 200 mAcm-2. After cycling test (300 cycles), the discharge potential retention of cell was about 92.7 %. Formation of catalyst-nanoparticles-embeded were achieved by electrospinning technology. The characterization of the materials were conducted with scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Raman analysis, mapping and Auger electron spectroscopy(AES). The results confirms that the nanoparticles on carbon fiber is Co3O4,The number of electrons transferred is calculated as 3.94 by rotating ring-disk electrode (RRDE). By full cell test, The discharge voltage of 1.13 V and specific capacity of 802 mAhg-1 are obtained at 50 mAcm-2. A maximum power density is 127 mWcm-2 at 175 mAcm-2. After cycling test(300cycles), the discharge potential is the same as 20 wt% Pt/C.

Global warming and depletion in fossil fuels have forced the society to search for alternate, clean sustainable energy sources. An obvious solution to the aforesaid problem lies in electrochemical energy storage systems like fuel cells and batteries. The desirable properties attributed to these devices like quick response, long life cycle, high round trip efficiency, clean source, low maintenance etc. have made them very attractive as energy storage devices. Compared to many advanced battery chemistries like nickel-metal hydride and lithium - ion batteries, metal-air batteries show several advantages like high energy density, ease of operation etc. The notable characteristics of metal - air batteries are the open structure with oxygen gas accessed from ambient air in the cathode compartment. These batteries rely on oxygen reduction and oxygen evolution reactions during discharging and charging processes. The efficiency of these systems is determined by the kinetics of oxygen reduction reaction. Platinum is the most preferred catalyst for many electrochemical reactions. However, high cost and stability issues restrict the use of Pt and hence there is quest for the development of stable, durable and active electrocatalysts for various redox reactions. The present thesis is directed towards exploring the electrocatalytic aspects of titanium carbonitride. TiCN, a fascinating material, possesses many favorable properties such as extreme hardness, high melting point, good thermal and electrical conductivity. Its metal-like conductivity and extreme corrosion resistance prompted us to use this material for various electrochemical studies. The work function as well as the bonding in the material can be tuned by varying the composition of carbon and nitrogen in the crystal lattice. The current study explores the versatility of TiCN as electrocatalyst in aqueous and non-aqueous media. One dimensional TiC0.7N0.3 nanowires are prepared by simple one step solvothermal method without use of any template and are characterized using various physicochemical techniques. The 1D nanostructures are of several µm size length and 40 ± 15 nm diameter (figure 1). Orientation followed by attachment of the primary particles results in the growth along a particular plane (figure 2). (a) (b) (c) Figure 1. (a) SEM images of TiC0.7N0.3 nanowires (b) TEM image and (c) High resolution TEM image showing the lattice fringes. (a) (b) (d) Figure 2. Bright field TEM images obtained at different time scales of reaction. (a) 0 h; (b) 12 h; (c) 72 h and (d) 144 h. The next aspect of the thesis discusses the electrochemical performance of TiC0.7N0.3 especially for oxygen reduction. Electrochemical oxygen reduction reaction (ORR) reveals that the nanowires possess high activity for ORR and involves four electron process leading to water as the product. The catalyst effectively converts oxygen to water with an efficiency of 85%. A comparison of the activity of different (C/N) compositions of TiCN is shown in figure 3. The composition TiC0.7N0.3 shows the maximum activity for the reaction. The catalyst is also very selective for ORR in presence of methanol and thus cross-over issue in fuel cells can be effectively addressed. Density functional theory (DFT) calculations also lead to the same composition as the best for electrocatalysis, supporting the experimental observations. Figure 3. Linear sweep voltammetric curves observed for different compositions of titanium carbonitride towards ORR. The next chapter deals with the use of TiC0.7N0.3 as air cathode for aqueous metal - air batteries. The batteries show remarkable performance in the gel- and in liquid- based electrolytes for zinc - air and magnesium - air batteries. A partial potassium salt of polyacrylic acid (PAAK) is used as the polymer to form a gel electrolyte. The cell is found to perform very well even at very high current densities in the gel electrolyte (figures 4 and 5). Figure 4 Photographs of different components of the gel - based zinc - air battery. (a) (b) Figure 5. a) Discharge curves at different current densities of 5, 20, 50 and 100 mA/cm2 for zinc-air system with TiC0.7N0.3 cathode b) Charge – discharge cycles at 50 mA/cm2 for the three electrode configuration with TiC0.7N0.3 nanowire for ORR and IrO2 for OER and Zn electrode (2h. cycle period). Similarly, the catalytic activity of TiC0.7N0.3 has also been explored in non-aqueous electrolyte. The material acts as a bifunctional catalyst for oxygen in non- aqueous medium as well. It shows a stable performance for more than 100 cycles with high reversibility for ORR and OER (figure 6). Li-O2 battery fabricated with a non-aqueous gel- based electrolyte yields very good output. (a) (b) (c) Figure 6. Galvanostatic charge –discharge cycles. (a) at 1 mA/cm2 (b) specific capacity as a function of no. of cycles (c) photographs of PAN-based gel polymer electrolyte. Another reaction of interest in non –aqueous medium is I-/I3-. redox couple. TiC0.7N0.3 nanowires show small peak to peak separation, low charge transfer resistance and hence high activity. The catalyst is used as a counter electrode in dye sensitized a solar cell that shows efficiencies similar to that of Pt, state of the art catalyst (figure 7). (a) (b) (c) Figure 7 (a) Cyclic voltammograms for I-/I3 - redox species on TiC0.7N0.3 nanowires (red), TiC0.7N0.3 particle (black) and Pt (blue). (b) Photocurrent density - voltage characteristics for DSSCs with different counter electrodes. TiC0.7N0.3 nanowire (black), TiC0.7N0.3 particle (blue), Pt (red). (c) Photograph of a sample cell. (a) (b) (c) (d) Figure 8 a) Comparison ORR activity for (i) NiTiO3(black), (ii) N-rGO (red), (iii) NiTiO3 – N-rGO (green) and (iv) Pt/C (blue) (b) Linear sweep voltammograms for OER observed on NiTiO3 – N-rGO composite (black), NiTiO3 (brown), N-rGO (blue), glassy carbon (red) in 0.5 M KOH. (c) Galvanostatic discharge curves of NiTiO3 – N-rGO as air electrode (d) Charge – discharge cycle at 5 mA/cm2 for the rechargeable battery with 10 min. cycle period. The last part of the thesis discusses about a ceramic oxide, nickel titanate. The electrocatalytic studies of the material towards ORR and OER reveal that the catalyst shows remarkable performance as a bifunctional electrode. A gel - based zinc - air battery fabricated with nickel titanate – reduced graphene oxide composite shows exceptional performance of 1000 charge-discharge cycles in the rechargeable mode (figure 8). Of course, the primary battery configuration works very well too The thesis contains seven chapters on the aspects mentioned above with summary and future perspectives given as the last chapter. An appendix based on TiN nanotubes and supercapacitor studies is given at the end.

In der vorliegenden Dissertation - Kathoden für Metall-Luft Batterien - steht die Komponente Gasdiffusionselektrode (GDE) – oftmals auch als Luft-Kathode bezeichnet – einer wässrigen Metall-Luft Batterie im Fokus. Ziel dieser Arbeit ist die Synthese und Charakterisierung verschiedener Katalysatorsysteme für die Sauerstoffreduktion und -evolution. Dabei soll auf die Verwendung von Edelmetallen verzichtet und der Einsatz von verfügbaren und günstigen Materialien bzw. Herstellungsprozessen favorisiert werden. Auf Basis von bekannten Materialklassen sollen repräsentative Katalysatoren synthetisiert und ihre katalytischen Aktivitäten für die Sauerstoffreduktion und -evolution bestimmt werden. Im Detail wird eine mögliche Korrelation der strukturellen Eigenschaften der Katalysatoren auf die katalytische Aktivität untersucht. Auf Basis dieser Erkenntnisse sollen die Katalysatoren modifiziert werden, um die katalytischen Eigenschaften weiter zu optimieren. Um einen geschlossenen Entwicklungszyklus in dieser Arbeit realisieren zu können, wird parallel ein kostengünstiger und skalierbarer Herstellungsprozess von GDEs entwickelt. Ein weiteres Ziel dieser Arbeit ist es, Konzepte für sekundäre Zink-Luft Energiespeicher zu erarbeiten und deren Umsetzung zu untersuchen. Dabei kommen die zuvor entwickelten Katalysatoren zum Einsatz. Die vorliegende Arbeit gliedert sich, nach der Darlegung der relevanten Grundlagen mit Stand der Wissenschaft und Technik, in vier Teilkapitel, in denen die einzelnen Ziele adressiert sind. Dies sind die Erforschung reiner Katalysatoren und hybrider Katalysatoren sowie die Etablierung eines Herstellungsprozesses für GDEs und die Implementierung dieser in sekundäre Zink-Luft Energiespeicher. Die experimentellen Grundlagen befinden sich im darauffolgenden Kapitel
The dissertation - Cathodes for metal-air batteries - focuses on the component gas diffusion electrode (GDE) - often referred to as air-cathode - of an aqueous metal-air battery. The aim of this work is the synthesis and characterization of different catalyst systems for the oxygen reduction reaction and oxygen evolution reaction. Instead of precious metals, available and cheap materials as well as low cost manufacturing processes are favored. Based on known material classes, representative catalysts will be synthesized and their catalytic activities for the oxygen reduction and evolution will be analyzed. In detail, a possible correlation of the structural properties of the catalysts with the catalytic activity is investigated. Based on these findings, the catalysts should be modified to further optimize the catalytic activity. In order to realize a closed development cycle in this thesis, a cost-effective and scalable manufacturing process for GDEs is being developed in parallel. Another goal of this work is to develop concepts for secondary zinc-air energy storage systems and to investigate their implementation. The present work is divided into four subchapters, in which the individual goals are addressed. These include research of pure catalysts and hybrid catalysts, as well as the establishment of a manufacturing process for GDEs and their implementation in secondary zinc-air energy storage systems

You already know, if you have read Reaction 6, that an electric current is a stream of electrons. If you have also read the section on redox reactions (Reaction 5), which you should, in preparation for this account, then you will also know that in a redox reaction electrons are transferred from one species to another. Although it is now far too late, had you had that information 150 or so years ago, then you might have realized that if those species were at the opposite ends of a piece of wire, the transfer of electrons would then take place in the form of an electric current travelling along the wire and you would have invented the electric battery. All the batteries that are used to generate electricity and drive portable electrical and electronic equipment, from torches, drills, phones, music players, laptops, through to electric vehicles, are driven by this kind of chemically produced flow of electrons. One of the earliest devices for producing a steady electric current was the ‘Daniell cell’, which was invented in 1836 by John Daniell (1790–1845) of King’s College, London in response to the demand in the nineteenth century of the then emerging technology of telecommunication for a steady, cheap source of electricity. I have already touched on the underlying reaction when I explained what happens when a piece of zinc, Zn, is dropped into a solution of copper sulfate (Reaction 5), and this section builds on that account. In that reaction copper is deposited on the zinc and the copper sulfate solution gradually loses its colour as blue Cu2+ ions are replaced by colourless Zn2+ ions. As this reaction takes place, electrons hop from the zinc metal onto Cu2+ ions nearby in the solution. If we were to stand there watching, we would see electrons snapping across from the zinc to the Cu2+ ions wherever the latter came within striking distance of the zinc surface. There would be electron transfer, but no net current of electricity. Daniell did what I outlined in the opening paragraph: he separated the zinc metal and copper ions, so that electrons released by zinc had to travel through an external wire to get to the Cu2+ ions.

Plug-in hybrid electric vehicles (PHEVs) have the potential to reduce green house gases emissions and provide a promising alternative to conventional internal combustion engine vehicles. However, PHEVs have not been widely adopted in comparison to the conventional vehicles due to their high costs and short charging intervals. Since PHEVs rely on large storage batteries relative to the conventional vehicles, the characteristics and design issues associated with PHEV batteries play an important role in the potential adoption of PHEVs. Consumer acceptance and adoption of PHEVs mainly depends on fuel economy, operating cost, operation green house gas (GHG) emissions, power and performance, and safety among other characteristics. We compare the operational performance of PHEV20 (PHEV version sized for 20 miles of all electric range) based on fuel economy, operating cost, and greenhouse gas (GHG) emissions through Pareto set point identification approach for 15 different types of batteries, including lithium-ion, nickel metal hydride (NiMH), nickel zinc (NiZn), and lead acid batteries. It is found that two from 15 batteries dominate the rest. Among the two, a NiMH (type ess_nimh_90_72_ovonic) gives the highest fuel economy, and a lithium-ion (type ess_li_7_303) yields the lowest operating cost and GHG emissions. From comparing nine batteries that are either on or close to the Pareto frontier, one can see that lithium-ion and NiMH batteries offer better fuel economy than lead-acid batteries. Though lithium-ion batteries bear clear advantage on operating costs and GHG emissions, NiMH and lead-acid batteries show similar performances from these two aspects.

The fossil fuel depletion and the CO2 warming due to the combustion are becoming serious environmental issues. Therefore, alternative energy systems minimumizing fossil fuels dependence are now required to be developted. Hydrogen is a best candidate for alternative energy sources friendly to the environment, but the essential point is how we produce hydrogen, independently of fossil fuel with a minimum energy input. This work aims first at proposing an alternative hydrogen gasifier from acid water by immersing ionicity metals, and second at applying the gasifier to a hydrogen ultra micro gas turbine electric generator charger system to construct hydrogen self supply energy system. First, D2SO4 as acid aqueous solutions and (Zn+Cu) and Zn plates as ionicity metals electrodes are selected here for H2 gasifier. The hydrogen production rate is experimentally characterized by changing the pH and temperature of the solution and the metal surface area. The gasifier has a good performance of hydrogen production of about 18 l/min at 60°C per unit electrode area under the pH = ∼1.0. This flow rate increases almost linearly to the acid temperature. In addition, the zinc resolved into the acid water, ZnSO4 in the case of D2SO4 for example, is able to be easily recrystalized on the electrode by reasonable electricity input of ∼2.5V. Second, the produced hydrogen is applied to ultra micro turbo electric generator / charger as hydrogen self supply system. This smart system is well applicable to hydrogen electric car, because of an ideal power source having small size, lightweight, low vibration, early start, no NOX and CO2 emissions, very low fuel consumption, long trip, etc. In the experiment a car turbo charger is converted into a compressorturbine system, and a high revolution electricity generator is connected to the turbo system. A combustor is designed for very low hydrogen consumption by ultra lean burning which causes almost no NOX emission due to low temperature < 1000°C. The turbo system is tested, resulting in a high efficiency, in spite of its small size, enough to generate electricity for charging a battery of electric car. By using these two elements, we aim to construct HSSES (Hydrogen Self Supply Energy System) which is found to be attractive especially for small electric cars and home cogenerations.

A novel copper-clad liquid crystal polymer material is proposed as a basic material for the construction of galvanic cells. Copper is an ideal material that allows not only the formation of conductor patterns in the material but also can be electroplated selectively with a wide variety of metals to create heterogeneous systems. The use of a novel mask-less patterning system described herein opens up the opportunity for micro fabrication of different microstructures that can be layered to form complex two and potentially three-dimensional micro fluidic networks. Achieving the photo-imprinting by the use of a novel mask-less system not only reduces the cost but also allows for ease and flexibility in making systems and is ideal for research and development environments. In this paper micro galvanic cells actuated by means of fluidic actuators have been designed and constructed. The electrochemical galvanic cells used as power source examples are a Daniell’s (Copper-Zinc) electrochemical battery, and an aluminum-air galvanic system. The choice for the electrochemical systems is discussed and some preliminary results are presented to show the levels of energy available. In addition, the basic concept of an electrically induced expansion mechanism for circuit activation on demand is described. Lastly, the mechanics of the suggested actuation mechanism are discussed.