Download or read book Design of Efficient Cobalt based Bi functional Catalysts for Zinc air Batteries written by Guihua Liu and published by . This book was released on 2019 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to its high theoretical specific energy and low-cost, rechargeable zinc-air batteries have attracted tremendous attention as a promising next-generation energy conversion system. However, there are some challenges that need to overcome before its practical application. One of the key issues is the slow reaction kinetics in the air cathode of the batteries towards the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). This would cause insufficient charge/discharge efficiency and poor cycle stability of the batteries. Therefore, the development of efficient ORR-OER bi-functional electrocatalysts with high catalytic activity and durability is essential for the development of rechargeable zinc-air batteries. In this work, a series of catalyst design strategies have been explored to improve the activity and durability of cobalt-based bi-functional catalysts especially under the oxidative condition of OER reaction. The latter would cause catalyst oxidation and aggregation, and therefore deteriorate the cycling performance of the bi-functional catalysts in zinc-air batteries. In the first study, a surface engineering approach was adopted to prepare efficient bi-functional catalyst consists of mildly oxidized, N-doped Co9S8 catalyst supported on N-doped reduce graphite oxide (O-N-Co9S8@N-RGO). The surface decorated electrocatalyst shows excellent activity for both ORR and OER, and maintains good stability over 900 charge-discharge cycles at 10 mA cm-2 in zinc-air battery. Interestedly, it was found that O-N-Co9S8 nanoparticles responsible for the OER reaction were completely converted into Co3O4 after OER reaction, indicating Co3O4 is the actual active phase for OER. On the basis of this observation, we propose and demonstrate that oxides in-situ generated cobalt oxides during OER reaction are more active than the directly calcined oxides. This work advances fundamental insight and the design of metal chalcogenides-based bi-functional "catalysts". On the recognition of the high catalytic activity of surface-engineered Co9S8 material, a three-dimensionally ordered mesoporous (3DOM) structured surface-engineered Co9S8 catalyst was developed to explore the benefits of the 3DOM structural design for its catalytic performance. Different from the N-RGO supported O-N-Co9S8, the 3DOM-Co9S8 catalyst is self-supported, which contains only an inner carbon layer within its mesoporous structure. Due to the 3D interconnected architecture and large surface area, the air electrode delivers excellent cell performance and cycling durability. However, the partial structure crush of N-Co9S8 after long-time OER testing was observed, demonstrating that the highly oxidative operating condition of rechargeable zinc-air batteries could cause significant structural integrity issues of porous chalcogenide electrocatalysts. Thus, in the last study, a new strategy focusing on the oxidation-resistive catalyst support design using oxygen vacancy (OV)-rich, low-bandgap semiconductor was proposed. The OVs promote the electrical conductivity of the semiconductor support, and at the same time offer a strong metal-support interaction (SMSI). The SMSI enables the catalysts with small metal size, high catalytic activity, and high stability. This strategy is demonstrated by successfully synthesizing ultrafine Co metal decorated 3DOM titanium oxynitride (3DOM-Co@TiOxNy). The catalyst not only exhibits good ORR-OER activities, but also shows excellent cycling stability in alkaline conditions, e.g. less than 1% energy efficiency loss over 900 charge-discharge cycles at 20 mA cm-2. Theoretical calculation confirmed that the high stability of this catalyst is attributed to the strong SMSI between Co and 3DOM-TiOxNy. This study will provide an alternative strategy for the design of efficient and durable non-precious electrocatalysts using OV-rich semiconductors as support materials. In summary, a series of catalyst design strategies for efficient and durable bi-functional ORR-OER catalyst were developed in this work. It was found that NH3 treatment is an effective surface-engineering approach to develop highly active ORR-OER catalysts. The in-situ transformation or oxidation of Co9S8 into Co3O4 observed in post-OER analysis advanced our understanding of the chemical, structural transformation and real catalytic phase for OER "catalyst". Moreover, the results show that the 3DOM design of self-supported Co9S8 catalyst could also benefits the catalytic performance by facilitating the mass and electronic transportation within the 3DOM framework. Finally, based on our up-to-date understanding of the OV in semiconductor physics and heterogeneous catalysis, a novel bi-functional catalyst support design strategy was proposed and demonstrated using OV-rich TiOxNy semiconductor. Excellent cycling stability and activity performance of such semiconductor supported cobalt catalyst in rechargeable zinc-air batteries is achieved.

Download or read book Spinel Oxides and Heteroatom doped Carbon Nano composite as Bi functional Oxygen Electrocatalyst for Rechargeable Zinc air Battery written by Moon Gyu Park and published by . This book was released on 2015 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: With continued increase in energy demand for high energy-required devices such as portable electronics and electric vehicles, development of innovative energy conversion and storage systems has attracted tremendous attention. Even though lithium-ion battery technology is currently the most developed energy storage technology and employed for multiple applications, their insufficient energy density and critical problem in intrinsic chemistry limit their further development for fulfilling the ultimate requirements. As an attractive alternative technology, metal-air battery has recently captured the spotlight as promising sustainable energy conversion and storage technology. Metal-air batteries with the open architecture provide many attractive characteristics containing environmental benignity, high power and energy densities. In addition, with a wide range of selection in different metals determines different energy capacity and efficiency. Among a various types of metal-air batteries, zinc-air battery system has especially been considered as the most mature technology due to its abundance, low cost, ease handling, and safe operation as well as high energy efficiency. However, some technological challenges of zinc-air batteries such as insufficient cycling durability, low charge/discharge activity and efficiency, and poor rate capability still must be addressed for future commercialization. These main challenges interrupting the development of electrically rechargeable zinc-air batteries are primarily due to very sluggish oxygen reduction and evolution reactions generated during discharge and charge processes on air electrode. The slow oxygen reactions create large overpotentials during both discharge and charge processes, which significantly decrease energy efficiency of zinc-air battery. Accordingly, the use of electrocatalysts in air electrode has been highly required to facilitate the reactions and even propel the zinc-air batteries to practical energy applications. Therefore, it is considerably necessary to develop highly active and durable bi-functional electrocatalysts toward both ORR and OER for the sake of successful commercialization of electrically rechargeable zinc-air batteries. In this point of view, design and synthesis of advanced oxygen electrocatalysts at low cost has been favorably considered. Despite extensive efforts made, however, developing air electrode catalysts with the high activity and the long durability at low cost remain a huge challenge because mostly precious metal-based catalysts such as platinum (Pt) and iridium (Ir) show greatly high activities toward ORR and OER, respectively. However, the use of the materials as electrocatalysts for zinc-air battery is highly challengeable in that they are extremely scarce, expensive, and unstable during the oxygen reactions. Therefore, it is significantly important to develop proper materials which are inexpensive, abundant, and stable during the oxygen reactions, where they are called “non-precious catalysts” primarily composed of transition metals or metal oxides, nano-carbons, and their hybrids. The strong objectives make us focus on the design of a class of novel composite architecture for high-performance electrochemical energy storage, electrically rechargeable zinc-air battery. In this work, the strategy is based on a fast solvation-induced assembly that directly exploits strong hydrophobicity of both cobalt oxide nanocrystals (Co3O4 NCs) and Nitrogen-doped carbon nanotubes (N-CNTs). A two-phase method is exploited to prepare the nearly mono-dispersed, highly crystalline, nano-sized cobalt oxide. The reaction of the two-phase system happens at the interface between the oil (nonpolar) and water (polar) phases and the interface is an exclusive site for both nucleation and growth. N-CNTs were synthesized by a single step chemical vapor deposition technique using either ferrocene as a catalyst and etylenediamine as a carbon source. Simply at first, cobalt oxide NCs and N-CNTs are dispersed in nonpolar solvent (e.g., toluene). Upon addition of polar solvent (e.g., methanol), solvation forces induce the hydrophobic cobalt oxide NCs to assemble around the hydrophobic CNTs, which leads to the formation of cobalt oxide NCs-decorated on the N-CNTs. As an electrochemical catalyst for air electrode, Co3O4 nanoparticle is a material with little ORR activity by itself. However, when it is decorated on Nitrogen-doped carbon nanotubes, their hybrid shows unexpected, surprisingly high performance in ORR that is further enhanced by nitrogen doping of N-CNTs. The Co3O4 NC/N-CNT hybrid exhibits comparable ORR catalytic activity but superior stability to a commercial carbon-supported Pt catalyst in alkaline solutions, thus leading to a novel bi-functional catalyst for ORR. The same hybrid is also highly active for OER, making it a high-performance non-precious metal-based bi-functional catalyst for both ORR and OER. The unusual catalytic activity arises from synergetic coupling effects between Co3O4 and N-CNTs. The full cell electrochemical catalytic activity is evaluated by preparing air electrodes of rechargeable zinc-air batteries utilizing ambient air to emphasize practicality. The galvanodynamic charge and discharge behaviors are superior to Pt/Carbon and N-CNT counterparts particularly at high applied current densities. Electrochemical impedance spectroscopy reveals that Co3O4 NC/N-CNT hybrid electrode results in significantly less internal, solid-electrolyte interface, and charge transfer resistances which lead to highly efficient electrochemical reactions. Superior rechargeability has also been confirmed where virtually no voltage drops are observed over 200 pulse cycles. The practicality of Co3O4 NC/N-CNT hybrid is highlighted by demonstrating comparable discharge voltages and greatly outperforming charge voltages with excellent electrochemical stability than commercial Pt/Carbon catalyst.

Download or read book Advanced Bifunctional Electrochemical Catalysts for Metal Air Batteries written by Yan-Jie Wang and published by CRC Press. This book was released on 2018-12-14 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal-air batteries (MABs) have attracted attention because of their high specific energy, low cost, and safety features. This book discusses science and technology including material selection, synthesis, characterization, and their applications in MABs. It comprehensively describes various composite bifunctional electrocatalysts, corrosion/oxidation of carbon-containing air cathode catalysts, and how improvements can be achieved in the catalytic activities of oxygen reduction reaction and oxygen evolution reaction and their durability/stability. This book also analyzes, compares, and discusses composite bifunctional electrocatalysts in the applications of MABs, matching the fast information of commercial MABs in requirements. Aimed at researchers and industry professionals, this comprehensive work provides readers with an appreciation for what bifunctional composite electrocatalysts are capable of, how this field has grown in the past decades, and how bifunctional composite electrocatalysts can significantly improve the performance of MABs. It also offers suggestions for future research directions to overcome technical challenges and further facilitate research and development in this important area.

Download or read book Bifunctional 2D structured catalysts for air electrodes in rechargeable metal air batteries written by Chengang Pei and published by OAE Publishing Inc.. This book was released on 2024-01-03 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inherent technical challenges of metal-air batteries (MABs), arising from the sluggish redox electrochemical reactions on the air electrode, significantly affect their efficiency and life cycle. Two-dimensional (2D) nanomaterials with near-atomic thickness have potential as bifunctional catalysts in MABs because of their distinct structures, exceptional physical properties, and tunable surface chemistries. In this study, the chemistry of representative 2D materials was elucidated, and the comprehensive analysis of the primary modification techniques, including geometric structure manipulation, defect engineering, crystal facet selection, heteroatom doping, single-atom catalyst construction, and composite material synthesis, was conducted. The correlation between material structure and activity is illustrated by examples, with the aim of leading the development of advanced catalysts in MABs. We also focus on the future of MABs from the perspective of bifunctional catalysts, definite mechanisms, and standard measurement. We expect this work to serve as a guide for the design of air electrode materials that can be used in MABs.

Download or read book Material Design and Engineering for Polymer Electrolyte Membrane Zinc air Batteries written by Jing Fu and published by . This book was released on 2018 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc-air batteries, whose advantages include relatively high energy density (1218 Wh kg-1), abundance of zinc in earth's crust, and very safe operational characteristics, are promising for applications in consumer electronics, electrified transportation, grid storage, and other fields. At the moment, primary zinc-air batteries are produced for low-drain electronic gadgets such as hearing aids. However, secondary (i.e., electrically rechargeable) zinc-air batteries have eluded widespread adoption due mainly to the slow reaction kinetics of oxygen evolution at the air electrode during recharge. A bifunctional oxygen electrocatalyst that can recharge the batteries more efficiently is required. Moreover, in the presence of aqueous alkaline electrolytes, zinc-air batteries suffer from low durability and performance loss due mainly to the formation of zinc dendrites during charging, the loss of aqueous electrolytes, the detachment of the catalyst layer and the precipitation of carbonates at the air electrode. These persistent issues have motivated a shift in electrolyte design towards efficient hydroxide ion-conductive polymeric electrolytes. A combination of efficient bifunctional oxygen electrocatalysts and polymeric electrolyte improvements may enable zinc-air batteries to be implemented in widespread applications in flexible/lightweight electronic devices and electric vehicles. In this work, I present a feasible strategy combining material innovations with engineering methods to develop a new type of zinc-air battery, i.e., a flexible, rechargeable polymer electrolyte membrane zinc-air battery (PEMZAB). In the first study, a proof of concept of a film-shaped, rechargeable PEMZAB was conducted by using a KOH-doped poly(vinyl alcohol) (PVA) gel electrolyte, porous zinc electrode and bifunctional air electrode comprising a commercial Co3O4 nanoparticles-loaded carbon cloth. Then, a novel hydroxide ion-conductive polymeric electrolyte membrane and an efficient bifunctional oxygen zinc-air battery performance. Specifically, highly quaternaized cellulose nanofibers were synthesized to produce a hydroxide ion-conductive electrolyte membrane (referred to as QAFC). The QAFC membrane shows advantages of a high ionic conductivity of 21.2 mS cm-1, good chemical stability, mechanical robustness and flexibility, and inhibition of zinc dendrites and carbonations. In addition to the QAFC electrolyte membrane development, a hybrid bifunctional oxygen electrocatalyst, consisting of cobalt oxysulfide nanoparticles and nitrogen-doped graphene nanomeshes (CoO0.87S0.13/GN), was prepared. The defect chemistries of both oxygen-vacancy-rich cobalt oxysulfides and edge-nitrogen-rich graphene nanomeshes lead to a remarkable improvement in electrocatalytic performance, where CoO0.87S0.13/GN exhibits strongly comparable catalytic activity and much better stability than the best-known benchmark noble metal catalysts. A simple, water-based filtration method for a direct assembly of the QAFC membrane and the CoO0.87S0.13/GN catalyst film was demonstrated with the PEMZAB. Such a fabrication approach enables intimate contact between the solid-solid catalyst-electrolyte interfaces for facile charge transfer. Moreover, benefiting from the performance improvement of the QAFC electrolyte membrane and the CoO0.87S0.13/GN bifunctional catalyst, the resulting battery possesses a higher energy density of 857.9 Wh kg-1 and a more stable cycling performance, over 300 hours of operation at 20 mA cm-2 under ambient conditions, than those of a battery using PVA-KOH gel electrolyte and commercial Co3O4 bifunctional catalysts. In the last study, the knowledge gained from the hybrid CoO0.87S0.13/GN bifunctional catalyst is transferred to the fabrication of a hybrid catalyst/current collector assembly for the bifunctional air electrode. In this assembly, a hair-like array of mesoporous cobalt oxide nanopetals in nitrogen-doped carbon nanotubes is grown directly on a stainless-steel mesh through chemical vapor deposition and electrodeposition methods. Such integrative design not only ensures a large number of catalytically active sites in a given electrode surface, but also increases the electron transfer between each individual catalyst and the conductive substrate. This advanced air electrode assembly further boosts the PEMZAB performance, with a high peak power density of 160.7 mW cm-2 at 250 mA cm-2 and a remarkable cycling durability: lasting over 600 hours of operation at 25 mA cm-2 under ambient conditions.

Download or read book Design and Engineering of Hierarchically Porous Transition Metal based Electrocatalysts for Rechargeable Zn air Batteries written by Moon Gyu Park and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrochemical oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the critical cathodic and anodic reactions, respectively, in electrically rechargeable Zn-air battery. With a variety of advantages including relatively high energy density (1218 Wh kg-1), the abundance of zinc in the earth, and secure handling and safe operation, electrically rechargeable (secondary) Zn-air battery technology has been regarded as highly promising energy applications in consumer electronics, electric vehicles, and smart grid storage. Zn-air batteries consist of not only zinc anode, polymer separator, and an alkaline electrolyte that are typical battery components, but also air-breathing cathode that makes Zn-"air" battery unique technology. Unlike other general battery systems such as lithium-ion batteries, there is no active material stored in cathode, but gaseous oxygen molecules in the air are used as the fuel for energy-generating reaction in the air cathode of Zn-air technology. The reactions occurring during battery discharge and charge are ORR and OER, respectively, which are mostly dominating the overall energy efficiency of the Zn-air battery system due to their intrinsically sluggish kinetics. The high energy barrier attributed to conversions between oxygen molecules diffused from the air and hydroxide ions in the electrolyte at the thin layer of the electrode leads to low charge/discharge energy efficiency and insufficient cycle stability hindering the commercialization of rechargeable Zn-air batteries to the market. Therefore, it is necessarily required to facilitate the slow kinetics of oxygen electrocatalytic reactions by using bifunctionally active and durable oxygen electrocatalyst materials to progress the reactions at practically viable and stable rates. With the use of bifunctional oxygen catalysts, kinetics of ORR and OER can be improved, leading to enhancement of Zn-air battery performances such as higher operating voltage and longer battery cycling life. The current best-known catalysts for ORR and OER are noble metals, including platinum (Pt) and iridium (Ir), respectively. However, high cost and scarcity of the precious metal-based catalysts hinder their employment in large scale energy applications. Furthermore, the electrochemical stability of these materials is well known to be very insufficient for long term usage even under typical device operating conditions. Therefore, the development of non-precious transition metal-based electrocatalysts has significantly been a momentous research field. Along with this movement, the facile synthesis and inexpensive preparation of highly active and durable electrocatalysts will take the top priority for the fulfillment of practically available rechargeable Zn-air battery technology in a variety of energy applications from portable electronics to electric vehicles and smart grid storage systems. In this work, novel design strategies of bifunctionally active and durable electrocatalysts possessing robust three-dimensional framework with hierarchical porosity are presented. A porous structure with a large surface area is essential to improve the oxygen electrocatalysis since the oxygen reactions take place at the surface of materials, where active sites reside, and thereby the large surface indicating plenty of catalytically active sites enhances kinetics of the reactions. Additionally, the porous architecture facilitates diffusion of oxygen gas molecules during the oxygen electrocatalysis, leading to enhanced mass transport of reactants and reduced overpotentials for ORR and OER polarizations, eventually resulting in improved activities. In addition to the improvement of activities, electrochemical stability is an essential fundamental property for the rational design of electrocatalysts. Thus, the 3D porous structure must have robust framework which can endure the highly oxidative environment in OER potential range. Therefore, the work presented in this thesis is aiming for the design and engineering of hierarchically porous transition metal-based electrocatalysts involving high porosity as well as electrocatalytically robust frameworks to improve the oxygen electrocatalytic activities and durability and thereby put the rechargeable Zn-air battery technology at a commercially viable level. In the first study, a facile polymer template-derived method has been used to synthesize three-dimensionally ordered meso/macro-porous (3DOM) spinel cobalt oxide as a bifunctional oxygen electrocatalyst. Physicochemical characterizations have revealed the morphology of the designed electrocatalyst to be a hierarchically meso/macro-porous metal oxide framework. As investigated by electrochemical characterizations, 3DOM Co3O4 shows far enhanced ORR and OER activities with improved kinetics compared to the bulk material. The enhancement is majorly attributed to the five times higher specific surface area and significantly greater pore volume, leading to the increased number of catalytic active sites and facilitated diffusion of oxygen molecules into and out of the structure, respectively. Moreover, the robust frameworks of 3DOM Co3O4 helps to withstand harsh cycling environments by exhibiting significantly small performance reduction and retaining the original morphology. The improved oxygen electrocatalytic activity and durability have been well demonstrated in the rechargeable Zn-air battery system. 3DOM Co3O4 presents remarkably enhanced rechargeability over 200 cycles while retaining quite comparable operating voltage gap in comparison with the precious benchmark catalyst. In the second study, palladium (Pd) nanoparticle is deposited on the surface of 3DOM Co3O4 via a simple chemical reduction process. The morphological advantages of the 3DOM framework, as confirmed in the previous study, are expected to facilitate diffusion of oxygen molecules into and out of the structure leading to the decreased overpotentials during ORR and OER. However, using metal oxides as electrocatalysts restricts fast electron transfer leading to limited activity for oxygen catalysis due to their intrinsically low electrical conductivity. Therefore, Pd nanoparticles are introduced into 3DOM Co3O4 by expecting synergy from the combination of the morphological advantage of 3DOM architecture and the significant thermodynamic stability as well as the excellent ORR activity of palladium metal. Electrochemical characterizations have revealed that the combination demonstrates synergistically improved bifunctional electrocatalytic activity and durability. Moreover, computational simulation via density-functional-theory (DFT) verifies Pd@Co3O4(3DOM) is superior in two ways; (i) Activity-wise: the d-band center of Pd deposited on 3DOM Co3O4 was found to decrease significantly, resulting in increased electron abundance at the Fermi level, which in turn enhanced the overall electrical conductivity; (ii) Durability-wise: synergistic hybrid of Pd and 3DOM Co3O4 resulted in a significantly improved corrosion resistance, due to the much higher carbon oxidation potential and bulk-like dissolution potential of Pd nanoparticles on 3DOM Co3O4. The remarkable electrochemical activities and stabilities of Pd@3DOM-Co3O4 obtained from the half-cell testing resulted in excellent rechargeability of a prototype Zn-air battery, demonstrating the synergistic introduction of Pd into 3DOM Co3O4. In the last study, a type of metal-organic-framework (MOF) is selected as a template to synthesize MOF-based electrocatalyst possessing robust framework with multi-level porosity. Typically, MOF materials consist of metal centers linked by functional organic ligands, which gives them unique material characteristics such as high porosity and surface area, morphological and compositional flexibility, and high crystallinity. Especially, transition metal-based Prussian blue analogue (PBA) nanocubes with a chemical formula MxII[MyIII(CN)6]z▪H2O, where MII and MIII are divalent and trivalent transition metal cations, respectively, are employed as the MOF precursors due to a several material advantages such as simple precipitation synthesis, various possible compositions, and robust structure with high porosity

Download or read book Transition Metal Oxides Anchored Onto Heteroatom Doped Carbon Nanotubes as Efficient Bifunctional Catalysts for Rechargeable Zinc air Batteries written by Alexandra McDougall and published by . This book was released on 2021 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is well known that renewable energy, e.g., wind and solar power, are intermittent energy sources. This means that energy storage devices are needed to store the energy for when it is needed. Currently Li-ion batteries are used as these energy storage devices, not only for alternative energy plants but in vehicles and electronics. There are several drawbacks with using Li-ion batteries, such as low safety, harmful Li mining practices, and high material costs. Rechargeable zinc-air batteries (ZABs) have gained a lot of traction recently due to their low cost, high safety, low environmental impact, and high theoretical energy density. However, a major obstacle is the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air electrode, which have hindered practical applications of ZABs. Precious metal catalysts have been applied to help mitigate the slow reaction kinetics; however, these are expensive and complicate manufacturing practices since two different precious metals are needed to achieve a bifunctional catalyst. Therefore, a low-cost bifunctional catalyst is needed to improve the slow reaction kinetics at the air electrode. This work focuses on further investigating a previously developed impregnation technique for air electrode preparation using an array of transition metal (Zn, Ni, Mn, and Co) oxide combinations. Various electrochemical and microstructural characterization techniques, e.g., linear sweep voltammetry, electrochemical impedance spectroscopy, electron microscopy, and energy dispersive X-ray spectroscopy, are used to examine each sample. The first study involved fabricating several catalysts by decorating nitrogen doped carbon nanotubes (N-CNTs) with either tri-metallic (Ni-Mn-Co) or tetra-metallic (Zn-Ni-Mn-Co) oxides, through a simple impregnation method into carbon-based, gas diffusion layers (GDL). Metal oxide compositions were selected based on previous results, preliminary electrochemical testing, and statistical design of experiments (DOE). Microstructural characterization was done using electron microscopy and X-ray photoelectron spectroscopy (XPS), and determined that the oxides fabricated were spinel oxides. Samples were electrochemically tested and the best candidates were subjected to full cell testing and bifunctional cycling for 200 charge/discharge cycles at 10 mA/cm2. The overall bifunctional efficiency, after cycling, of the best NiMnCoOx/N-CNT and ZnNiMnCoOx/N-CNT catalysts was 53.3% and 56.4%, respectively; both outperformed Pt-Ru/C in both overall bifunctional efficiency (38%) and cycling stability. The maximum power density of one of the tetra-metallic oxides exceeded that of Pt-Ru/C (110 mW/cm2) at 134 mW/cm2. The addition of Zn with Ni-Mn-Co oxide particles showed improved cycling stability and overall bifunctional efficiency. The second study investigated the effect of co-doping of carbon nanotubes with nitrogen and sulfur (N,S-CNTs), combined with tri-metallic and tetra-metallic oxides, on the ORR and OER reaction kinetics at the air electrode. The best tri-metallic (Ni-Mn-Co) oxide and tetra-metallic (Zn-Ni-Mn-Co) oxide from the first study were used in this investigation. Microstructural characterization analysis revealed that the Co and Mn valences increased for the Ni-Mn-Co and Zn-Ni-Mn-Co oxides, respectively. Electrochemical testing revealed that the Ni-Mn-Co oxide was comparable to the Pt-Ru/C catalyst with a power density of ~95 mW/cm2 and Zn-Ni-Mn-Co oxide was comparable to the Pt-Ru/C catalyst with an efficiency of 56.0% at 20 mA/cm2. The addition of sulfur to the N-CNTs positively impacted the Ni-Mn-Co oxide, leading to a round trip bifunctional cycling efficiency of 55.1% for 200 charge-discharge cycles at 10 mA/cm2. The impact of sulfur did not have a positive impact on the Zn-Ni-Mn-Co oxide; the LSV results were significantly worse than the equivalent oxide on N-CNTs and the full cell testing was comparable to the N-CNT oxide. Both tri-metallic and tetra-metallic oxides outperformed Pt-Ru/C during bifunctional cycling.

Download or read book Zinc Air Batteries written by Zongping Shao and published by John Wiley & Sons. This book was released on 2023-01-04 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc–Air Batteries Authoritative and comprehensive resource covering foundational knowledge of zinc–air batteries as well as their practical applications Zinc–Air Batteries provides a comprehensive understanding of the history and development of Zn–air batteries, with a systematic overview of components, design, and device innovation, along with recent advances in the field, especially with regards to the cathode catalyst design made by cutting-edge materials, engineering processes, and technologies. In particular, design principles regarding the key components of Zn–air batteries, ranging from air cathode, to zinc anode, and to electrolyte, are emphasized. Furthermore, industrial developments of Zn–air batteries are discussed and emerging new designs of Zn–air batteries are also introduced. The authors argue that designing advanced Zn–air battery technologies is important to the realization of efficient energy storage and conversion—and, going further, eventually holds the key to a sustainable energy future and a carbon-neutral goal. Edited and contributed to by leading professionals and researchers in the field, Zinc–Air Batteries also contains information regarding: Design of oxygen reduction catalysts in primary zinc–air batteries, including precious metals, single-atoms, carbons, and transition metal oxides Design of bifunctional oxygen catalysts in rechargeable zinc–air batteries, covering specific oxygen redox reactions and catalyst candidates Design of three-dimensional air cathode in zinc–air batteries, covering loading of carbon-based and transition metal catalysts, plus design of the three-phase interface Design of electrolyte for zinc–air batteries, including liquid electrolytes (e.g., alkaline) and gel polymer electrolytes (e.g., PVA hydrogel) For students, researchers, and instructors working in battery technologies, materials science, and electrochemistry, and for industry and government representatives for decision making associated with energy and transportation, Zinc–Air Batteries summarizes the research results on Zn–air batteries and thereby helps researchers and developers to implement the technology in practice.

Download or read book Energy Storage and Conversion Devices written by Anurag Gaur and published by CRC Press. This book was released on 2021-10-28 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a state-of-the-art overview of the research and development in designing electrode and electrolyte materials for Li-ion batteries and supercapacitors. Further, green energy production via the water splitting approach by the hydroelectric cell is also explored. Features include: • Provides details on the latest trends in design and optimization of electrode and electrolyte materials with key focus on enhancement of energy storage and conversion device performance • Focuses on existing nanostructured electrodes and polymer electrolytes for device fabrication, as well as new promising research routes toward the development of new materials for improving device performance • Features a dedicated chapter that explores electricity generation by dissociating water through hydroelectric cells, which are a nontoxic and green source of energy production • Describes challenges and offers a vision for next-generation devices This book is beneficial for advanced students and professionals working in energy storage across the disciplines of physics, materials science, chemistry, and chemical engineering. It is also a valuable reference for manufacturers of electrode/electrolyte materials for energy storage devices and hydroelectric cells.

Download or read book Advanced Materials for Clean Energy written by Qiang Xu and published by CRC Press. This book was released on 2015-04-06 with total page 623 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research for clean energy is booming, driven by the rapid depletion of fossil fuels and growing environmental concerns as well as the increasing growth of mobile electronic devices. Consequently, various research fields have focused on the development of high-performance materials for alternative energy technologies.Advanced Materials for Clean Ene

Download or read book Energy Efficient Strategy for Designing Metal organic Frameworks Based Bifunctional Electrocatalysts and High Performing Rechargeable Zinc air Batteries written by Juntao Li and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Catalysis written by Bruce C. Gates and published by Academic Press. This book was released on 2001-05-14 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface science emerged in the 1960s with the development of reliable ultrahigh vacuum apparatus, providing exact structures of surfaces of metal single crystals, information about their compositions, and relationships between surface structure and composition and catalytic reaction rates. Catalysis, the acceleration of a chemical reaction by a catalyst (substance), provided much of the driving force for the early development of surface science. As surface science continues its rapid development, this book illustrates how it is still driven by the challenges of catalysis and how both theory and scanning tunneling microscopy have forcefully emerged as essential tools. It is also evident how surface science continues to serve as the foundation of catalytic science. This is a compendium written by leading surface scientists presenting an incisive assessment of up-to-date theoretical and experimental results constituting the foundation of fundamental understanding of surface catalysis. This paperback.

Download or read book Zinc Air Batteries written by Shengjie Peng and published by Springer Nature. This book was released on 2023-01-01 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to discuss the cutting-edge materials and technologies for zinc-air batteries. From the perspective of basic research and engineering application, the principle innovation, research progress, and technical breakthrough of key materials such as positive and negative electrodes, electrolytes, and separators of zinc-air batteries are discussed systematically, which can be used to guide and promote the development of zinc-air battery technology. We do believe that our experiences and in-depth discussions would make this book useful for researchers at all levels in the energy area and provide them with a quick way of understanding the development of zinc-air batteries.

Download or read book Design and Construction of Self supported Bi metal Electrode and Hierarchical Bi functional Catalyst for Rechargeable Zinc air Battery written by Tianshun Su and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PEM Fuel Cell Electrocatalysts and Catalyst Layers written by Jiujun Zhang and published by Springer Science & Business Media. This book was released on 2008-08-26 with total page 1147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane (PEM) fuel cells are promising clean energy converting devices with high efficiency and low to zero emissions. Such power sources can be used in transportation, stationary, portable and micro power applications. The key components of these fuel cells are catalysts and catalyst layers. “PEM Fuel Cell Electrocatalysts and Catalyst Layers” provides a comprehensive, in-depth survey of the field, presented by internationally renowned fuel cell scientists. The opening chapters introduce the fundamentals of electrochemical theory and fuel cell catalysis. Later chapters investigate the synthesis, characterization, and activity validation of PEM fuel cell catalysts. Further chapters describe in detail the integration of the electrocatalyst/catalyst layers into the fuel cell, and their performance validation. Researchers and engineers in the fuel cell industry will find this book a valuable resource, as will students of electrochemical engineering and catalyst synthesis.

Download or read book Metal Air Batteries written by Xin-bo Zhang and published by John Wiley & Sons. This book was released on 2019-02-11 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the research developments in the burgeoning field of metal-air batteries An innovation in battery science and technology is necessary to build better power sources for our modern lifestyle needs. One of the main fields being explored for the possible breakthrough is the development of metal-air batteries. Metal-Air Batteries: Fundamentals and Applications offers a systematic summary of the fundamentals of the technology and explores the most recent advances in the applications of metal-air batteries. Comprehensive in scope, the text explains the basics in electrochemical batteries and introduces various species of metal-air batteries. The author-a noted expert in the field-explores the development of metal-air batteries in the order of Li-air battery, sodium-air battery, zinc-air battery and Mg-O2 battery, with the focus on the Li-air battery. The text also addresses topics such as metallic anode, discharge products, parasitic reactions, electrocatalysts, mediator, and X-ray diffraction study in Li-air battery. Metal-Air Batteries provides a summary of future perspectives in the field of the metal-air batteries. This important resource: -Covers various species of metal-air batteries and their components as well as system designation -Contains groundbreaking content that reviews recent advances in the field of metal-air batteries -Focuses on the battery systems which have the greatest potential for renewable energy storage Written for electrochemists, physical chemists, materials scientists, professionals in the electrotechnical industry, engineers in power technology, Metal-Air Batteries offers a review of the fundamentals and the most recent developments in the area of metal-air batteries.

Download or read book Cobalt Hexamine HMT Metal Organic Framework derived Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions written by Yue Niu and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With the high requirement of increasing people's living standards and building a more sustainable society, electrochemical energy storage devices with large energy density, high power density, and long term durability are greatly needed to mitigate the consumption of fossil fuels. Among all those well-known energy storage systems, zinc-air batteries are one of the most appealing candidates due to sufficient and inexpensive resources applied, promising energy density, as well as the high reduction potential of zinc. However, Zn-air batteries always suffer from relatively high overpotential, which is predominantly originated from the sluggish kinetics of oxygen electrocatalytic reactions. Enormous efforts have been devoted to the development of active bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Although noble-metal catalysts, such as platinum, iridium, and their alloys have been proved to own outstanding electrochemical performances for oxygen electrocatalysis, their insufficient catalytic bifunctionality, rarity and high cost hinder the commercial utilization. As a result, the design and synthesis of cost-effective, robust and highly stable bifunctional electrocatalysts to replace noble metal catalysts for zinc-air batteries are greatly desirable to realize the commercialization of Zn-air batteries. In recent years, the metal-organic frameworks (MOFs) are burgeoning as attractive precursors for the fabrication of transition-metal based bifunctional oxygen electrocatalysts with controllable nanostructures due to the structural and compositional advantages of the MOF. Herein, a layered Co-hexamine coordination framework is prepared and used as an efficient precursor to synthesize high-performance ORR/OER bifunctional electrocatalyst featured with cobalt oxide and cobalt phosphide heterostructured structure (denoted as CoO/CoxP).