Zinc-air Battery System Research Articles

Leaf-like Multiphase Metal Phosphides as Bifunctional Oxygen Electrocatalysts toward Rechargeable Zinc-Air Batteries.

Developing a bifunctional oxygen electrocatalyst is crucial to improve the reversibility and cycle life of a rechargeable zinc-air battery (RZAB). Here, transition metal phosphides (TMPs) with a leaf-like hierarchical structure and multiphase composition can be synthesized by the "alloying-dealloying-phosphating" strategy. The as-prepared P-NiCo(1:1) electrode takes advantage of its internal dense nanoholes and synergistic effects induced by NiCoP-containing polyphase to reveal multifunctional catalysis, such as OER and ORR. In combination of these advantages, P-NiCo(1:1) exhibits an extremely low OER overpotential of 220 mV at 10 mA cm-2, a higher half-wave potential of 0.79 V for ORR, and a smaller potential difference (ΔE) of 0.66 V. The liquid RZAB with P-NiCo(1:1) as a cathodic bifunctional catalyst delivers a higher open-circuit voltage (OCV), a larger power density of 175 mW cm-2, and longer cycling life for more than 180 h. Even when applied in solid-state flexible RZABs, the lightweight module could start high-power devices. With theoretical confirmation, the major phase NiCoP of P-NiCo(1:1) is helpful to increase the density of states, regulate the d-band center, and decrease the energy barrier to 2.13 eV, which are significantly superior to those of Co2P and Ni2P. It is believable that the synthetic strategy and activity-promoting mechanism acquired from this research can offer a guide to designing a promising rechargeable zinc-air battery system.

A photothermal assisted zinc-air battery cathode based on pyroelectric and photocatalytic effect

Zinc–air battery as one of the new generations of battery system, its theoretical specific energy is as high as 1086 Wh kg−1, specific capacity up to 820 mAh/g, and zinc has the advantages of environmental friendliness, resource abundance, low cost and good safety, so it has attracted much attention. However, due to its slow reaction kinetic process, zinc–air battery will produce a large charging overpotential usually up to 2 V, it is far beyond the theoretical voltage of 1.65 V, so reducing the overpotential of zinc–air batteries is extremely necessary, and the most common way to solve this problem is to use excellent catalyst cathode to improve the oxygen reduction and oxygen evolution kinetics of zinc–air batteries. So we developed a new photothermal assisted zinc–air battery system with Hollow carbon nanosphere@poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)@CdS(HCN@PVTC@CdS) photocathode, the pyroelectric and photocatalysis effect can effectively promote the reaction kinetics and reduce the reaction overpotential. With the pyroelectric and photocatalysis synergistic effect, the zinc–air has displayed a high discharge potential of 1.33 V and a low charging potential of 1.5 V with good cycle stability. This multi-assist technology with built-in electric and light fields paves the way for the development of high-performance zinc–air batteries and other energy storage systems.

Green Energy Storage: Chitosan-Avocado Starch Hydrogels for a Novel Generation of Zinc Battery Electrolytes.

Meeting the ever-increasing global energy demands through sustainable and environmentally friendly means is a paramount challenge. In response to this imperative, this study is dedicated to the development of biopolymer electrolytes, which hold promise for improving the efficiency, safety, and biodegradability of energy systems. The present study aims to evaluate hydrogels synthesized from chitosan biopolymer and starch from avocado seed residues in different ratios, and dried using freeze-thawing and freeze-drying techniques. Epichlorohydrin was used as a chemical crosslinker to create a suitable degree of swelling using an ionic solution. Physical freezing crosslinking strategies such as freezing-thawing and freezing-drying were performed to generate a denser porous structure in the polymer matrix. Subsequently, synthesized electrolytes were immersed in 12 M KOH solution to improve their electrochemical properties. The effect of the different ratios of starch in the hydrogels on the structural properties of the materials was evaluated using characterization techniques such as FTIR and XRD, which allowed to confirm the crosslinking between chitosan and starch. The electrochemical performance of the hydrogels is assessed using electrochemical impedance spectroscopy. A maximum conductivity value of 0.61 S·cm-1 was achieved at room temperature. The designed materials were tested in prototype zinc-air batteries; their specific capacity value was 1618 mA h·g-1, and their obtained power density was 90 mW·cm-2. These substantial findings unequivocally underscore the potential of the synthesized hydrogels as highly promising electrolytes for the application in zinc-air battery systems.

Carbon-Encapsulated Cobalt Phosphide Nanowires as Trifunctional Catalysts for Water Splitting Devices

Cobalt-based catalysts have been widely proved to be promising electrocatalysts for oxygen reduction (ORR), hydrogen evolution (HER), and oxygen evolution (OER). In this paper, to maximize the trifunctional reactivity of the catalyst, a series of one-dimensional carbon-coated cobalt-based compound nanowires with changed anions were reported, and their trifunctional activities were systematically investigated. Among the cobalt-based compounds with different anions, carbon-encapsulated cobalt phosphide nanowires (CoP/C NWs) show impressive trifunctional catalytic activity toward ORR, OER, and HER. Using CoP/C NWs as a trifunctional electrocatalyst, an integrated device of the two-electrode water splitting device powered by the zinc–air battery system was realized. The assembled zinc–air battery exhibits high power density (115 mW cm–2) and long-term cycle stability (over 350 h, 1050 cycles). This work provides an insight into the effects of anion substitution on electrocatalytic activity and provides a highly effective feasibility for the design of energy-related devices with high-activity and durable catalysts.

3D Spiral Zinc Electrode for Rechargeable Aqueous Zinc-Air Battery

Zinc metal has emerged as seeded anode material in the field of high-efficiency aqueous metal-air battery system due to the advantages of abundant reserves, strong reversibility and high capacity. Unfortunately, the conventional zinc electrodes commonly adopt a flat structure, and the dendrite accumulation and corrosion during the cycle process lead to sub-optimal efficiency and performance. Herein, the zinc electrode is designed as a three-dimensional (3D) spiral structure to improve the utilization efficiency of zinc and the quality of the battery. Compared with the zinc plate, the 3D spiral zinc electrode can shorten the movement distance of the particles in space and the operation period in time, increase the specific surface area of the reaction, reduce the resistance of mass and charge transfer, and achieve the effect of optimizing the performance of the battery system. The results show that the aqueous zinc-air battery made of 3D spiral zinc electrode exhibits better charge-discharge characteristics, higher power density and narrower voltage windows. This study demonstrates a zinc anode with simple feasibility properties and a special structure, aiming to provide a new research direction and innovation strategy for the development of high-performance rechargeable zinc-air battery systems.

A Long‐Overlooked Pitfall in Rechargeable Zinc–Air Batteries: Proper Electrode Balancing

AbstractIn times of an ever‐increasing demand for portable energy storage systems, post‐lithium‐based battery systems are increasingly coming into the focus of current research. In this realm, zinc–air batteries can be considered a very promising candidate to expand the existing portfolio of lithium‐based rechargeable battery systems due to their high theoretical energy density of 1086 Wh kg−1. Despite a steady increase in research over the past 5 years, a breakthrough in realizing fully electrically rechargeable zinc–air batteries has yet to come. This perspective article highlights pitfalls that have probably hampered the development of rechargeable zinc–air batteries over years. This involves a fundamental evaluation of the zinc–air battery system, whereby fallacies of an alleged rechargeability are uncovered. Especially, the electrode balancing of the zinc anode as well as the interface between anode and electrolyte is focused herein. Known phenomena such as morphological changes are re‐evaluated by taking the contrasting battery stresses from shallow discharge to a highly desirable deep discharge into account. Existing challenges are discussed and prospected based on current approaches aiming to shed new light on a fundamental understanding and an opening of new avenues for rechargeability in zinc–air batteries.

Sustainable Graphene Quantum Dots (GQDs) as an Electrolyte Additive for Zinc-Air Battery System

Sustainable Graphene Quantum Dots (GQDs) as an Electrolyte Additive for Zinc-Air Battery System

MOF-Derived Nanoporous Carbon As an Efficient Bifunctional Oxygen Electrocatalyst for Erzabs

Zinc-air batteries are cost-effective batteries that possess a high energy density (1086 Wh Kg-1), compared to other conventional battery systems. In order to improve the electrochemical performance of electrically rechargeable zinc-air batteries (ERZABs), an effective bifunctional oxygen electrocatalyst is required. Hence, the development of non-noble metal bifunctional catalysts for ORR and OER is of prime importance. The transition metal-based catalysts have increasing demand since they are promising alternatives, in terms of cost and durability, to noble metal catalysts. Metal-organic frameworks (MOF) based catalysts show high catalytic activity due to adjustable pore size, ultra-high surface area, and structural designability[1].Increasing porosity can augment the catalytic activity by increasing the surface area, thereby enhancing the ORR kinetics.In the present work, a CFZ-NPC (CoFeZn-MOF derived nanoporous carbon) was synthesized via hydrothermal method and investigated as a bifunctional catalyst for rechargeable zinc-air batteries[2]. The catalyst shows a high electrochemical activity towards oxygen reduction reaction with a half-wave potential of 830 mV vs. RHE and a comparable oxygen evolution activity (overpotential of 379 mV vs. RHE at 10 mA cm-2 ) with IrO2 (Over potential of 377 mV at 10 mA cm-2). The binder-free CFZ-NPC air electrode when applied into a Zinc-air battery system, delivers a low charge-discharge potential gap of 862 mV at 5 mA cm-2. Interestingly, the catalyst possesses an excellent electrochemical performance in the electrically rechargeable Zn-air battery over 1000 cycles at selected DOD for 157 h with a specific capacity of 890 mAh g(Zn) -1 without much efficiency drop.Financial support from Department of Science and Technology, Govt. of India under research grant number DST/TMD/MECSP/2K17/20 is gratefully acknowledged References; [1] Ren, Shuangshuang et al. 2020. “Bifunctional Electrocatalysts for Zn-Air Batteries: Recent Developments and Future Perspectives.” Journal of Materials Chemistry A 8(13): 6144–82.[2] Tang, Jing et al. 2016. “Bimetallic Metal-Organic Frameworks for Controlled Catalytic Graphitization of Nano porous Carbons.” Nature Publishing Group (April): 1-8.

Spatiotemporally super-resolved dendrites nucleation and early-stage growth dynamics in Zinc-ion batteries

Safety and lifespan problems caused by the zinc dendrite formation continue to impede the application of zinc-based batteries. To address this severe issue, it is crucial to fully understand the nanoscale nucleation and early-stage dendrite growth process. However, the key dynamic process can hardly be resolved at the nanoscopic level under ambient working conditions with the current in situ / operando methods. Here, we develop a highly sensitive, super-resolution operando imaging approach for directly investigating the initial electroplating process in the zinc-air battery system. With this approach, millisecond/nanometer-resolution observation is achieved, providing nucleation rate, growth heterogeneity, and direction information at the single zinc nuclei level, and revealing nanoscopic details of early-stage dendrite growth. The spatiotemporally super-resolved observation elucidates that dynamic change in the local electrochemical environment is the key factor for the formation of the zinc dendrites. This novel straightforward approach can enable a deep understanding of the electrochemical interfacial issues and facilitate problem solving in diverse battery systems. Super-resolution operando imaging of zinc initial electroplating process Millisecond/nanometer resolution observation of single zinc nuclei formation Zinc nucleation rate, growth heterogeneity, and direction obtained Super-resolved early-stage dendrites formation and role of zinc depletion In-depth understanding of initial electroplating dynamics is crucial for designing/developing safer batteries. Here, Ye et al. develop a super-resolution microscopy with nanoscale and millisecond resolution, that enables the direct imaging and analysis of highly dynamic zinc nucleation and early-stage dendrite growth under ambient conditions. This new approach can be used for probing key interfacial electrochemical issues in diverse battery systems.

Zeolitic Imidazolate Framework-Derived Ordered Pt–Fe Intermetallic Electrocatalysts for High-Performance Zn-Air Batteries

Aiming to explore novel oxygen reduction reaction (ORR) catalysts with advanced electrochemical performance and economical and long-term stability is crucial to fuel cells or metal-air batteries. Herein, ordered Pt–Fe intermetallic with an ultralow Pt loading is facilely achieved via the thermal treatment of Pt nanocrystals anchored to the Fe, N-codoped surface-functioned carbon derived from zeolitic imidazolate frameworks. Benefiting from the ordered Pt–Fe intermetallic formed by the rationally applied calcination treatment, the optimized catalyst shows a larger mass activity and better long-term durability compared with Pt/C. Besides, when the optimized sample is applied in the configuration of a zinc-air battery system, it has a higher maximum power density, a better specific capacity as well as a longer discharge time, surpassing those of the Pt/C catalyst.

A new silicon oxycarbide based gas diffusion layer for zinc-air batteries

Rational material designs play a vital role in the gas diffusion layer (GDL) by increasing the oxygen diffusion rate and, consequently, facilitating a longer cycle life for metal-air batteries. In this work, a new porous conductive ceramic membrane has been developed as a cathodic GDL for zinc-air battery (ZAB). The bilayered structure with a thickness of 390 μm and an open porosity of 55% is derived from a preceramic precursor with the help of the freeze tape casting technique. The hydrophobic behaviour of the GDL is proved by the water contact angle of 137.5° after the coating of polytetrafluoroethylene (PTFE). The electrical conductivity of 5.59 * 10−3 S/cm is reached using graphite and MWCNT as filler materials. Tested in a ZAB system, the as-prepared GDL coated with commercial Pt-Ru/C catalyst shows an excellent cycle life over 200 cycles and complete discharge over 48 h by consuming oxygen from the atmosphere, which is comparable to commercial electrodes. The as-prepared electrode exhibits excellent ZAB performance due to the symmetric sponge-like structure, which facilitates the oxygen exchange rate and offers a short path for the oxygen ion/-electron kinetics. Thus, this work highlights the importance of a simple manufacturing process that significantly influences advanced ZAB enhancement.

A competitive self-powered sensing platform based on a visible light assisted zinc-air battery system.

We developed a novel competitive self-powered sensing platform based on the discharge process of a visible light assisted zinc-air battery system for the detection of targets with a high open circuit potential signal (Eocpt = 1.5 V), which is a splendid signal among state-of-the-art self-powered sensing platforms.

Dual-active-sites design of CoSx anchored on nitrogen-doped carbon with tunable mesopore enables efficient Bi-Functional oxygen catalysis for ultra-stable zinc-air batteries

Developing highly efficient oxygen electrode is particular important in the application of electrochemical energy conversion and storage technologies. In this work, we report the synthesis of highly dispersed CoSx nanocrystals anchored on N-doped mesoporous carbon (CoSx@NMC) network electrode. CoSx@NMC, derived from Fe/Co dual tuning nitrogen/sulfur-containing polymer as carbon precursor, manifests discrete dual-active-sites endowing excellent bifunctional catalytic activity toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The zinc-air battery system assembled from this CoSx@NMC electrode exhibits an open circuit voltage of 1.44V (vs. Zn/Zn+) and a peak power density of 269.7 mW cm−2. Notably, it exhibits a super stability in the galvanostatic discharge of 5 mA and 50 mA, and the voltage could be maintained stable at 1.25V over 90h galvanostatic discharge. Rechargeable zinc-air battery delivers an excellent cycling stability beyond 1288 charge/discharge cycles. The superior electrochemical catalytic properties for ORR/OER are attributed to the strongly coupled pyridine-N, graphitic-N and nanoscale CoSx, which can promote the simultaneous exposure of both OER and ORR active centres. Further investigations reveal that the microstructure of the mesoporous carbon might experience a structural remodeling during the charge/discharge process.

Selective Ion Transporting Polymerized Ionic Liquid Membrane Separator for Enhancing Cycle Stability and Durability in Secondary Zinc-Air Battery Systems.

Rechargeable secondary zinc-air batteries with superior cyclic stability were developed using commercial polypropylene (PP) membrane coated with polymerized ionic liquid as separators. The anionic exchange polymer was synthesized copolymerizing 1-[(4-ethenylphenyl)methyl]-3-butylimidazolium hydroxide (EBIH) and butyl methacrylate (BMA) monomers by free radical polymerization for both functionality and structural integrity. The ionic liquid induced copolymer was coated on a commercially available PP membrane (Celguard 5550). The coat allows anionic transfer through the separator and minimizes the migration of zincate ions to the cathode compartment, which reduces electrolyte conductivity and may deteriorate catalytic activity by the formation of zinc oxide on the surface of the catalyst layer. Energy dispersive X-ray spectroscopy (EDS) data revealed the copolymer-coated separator showed less zinc element in the cathode, indicating lower zinc crossover through the membrane. Ion coupled plasma optical emission spectroscopy (ICP-OES) analysis confirmed over 96% of zincate ion crossover was reduced. In our charge/discharge setup, the constructed cell with the ionic liquid induced copolymer casted separator exhibited drastically improved durability as the battery life increased more than 281% compared to the pure commercial PP membrane. Electrochemical impedance spectroscopy (EIS) during the cycle process elucidated the premature failure of cells due to the zinc crossover for the untreated cell and revealed a substantial importance must be placed in zincate control.

Novel Anode for High Power Zinc-Air Batteries

This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in zinc-air battery systems. The improved performance of the anodes in two different sizes of battery is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated excellent material utilization at various discharge rates. The zinc-air battery powered an electric bicycle and demonstrated good results.

Fibrous zinc anodes for high power batteries

This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc–air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc–air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc–air battery was used to power an electric bicycle and demonstrated good results.