Electrocatalysts For Rechargeable Zinc-air Batteries Research Articles

A novel layered cobalt oxide Ba2Co9O14 as an efficient and durable bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries

In this work, a layered cobalt oxide Ba2Co9O14 (BCO), belongs to a Ban+1ConO3n+3(Co8O8) family composed by alternating CdI2 based layers (Co8O8) with n (111) perovskite blocks (Ban+1ConO3n+3), has been developed as a potential bifunctional oxygen electrocatalyst candidate for efficient and durable rechargeable zinc-air battery (ZAB) application. Because of the greatly increased the specific surface area caused by ball-milling, the as-milled BCO material exhibits strongly enhanced bifunctional electrocatalytic activity towards oxygen reduction and oxygen evolution reaction in alkaline medium. Moreover, the assembled BCO-based ZAB yields an effectively improved maximum output power density of 166 mW cm−2, a considerable specific capacity of 789 mAh g−1, and excellent charge-discharge cycle stability of over 250 h at 10 mA cm−2 with over 1500 cycles.

FeNi alloy embedded in three-dimensional nitrogen-doped porous carbon as bifunctional oxygen electrocatalysts for rechargeable Zn-air batteries

Iron‑nickel (FeNi) alloy is one of the efficient bifunctional oxygen electrocatalysts for zinc-air batteries (ZABs). However, FeNi alloy nanoparticles prepared by traditional synthesis strategies are easy to agglomerate and have non-uniform sizes, which is not conducive to the improvement of catalytic activity and stability. Here, we have successfully encapsulated two different kinds of nitrogen-rich metal phthalocyanines (MPcs) in situ doping in zeolitic imidazolate framework (ZIF-8) homogeneously by the “double solvents” method. The ligand nitrogen and macrocyclic structure of MPcs encapsulated in ZIF-8 not only helps metal dispersion and enhances the metal-ligand‑nitrogen (M-Nx) structure, but also enhances the graphitisation of three-dimensional (3D) porous carbon after pyrolysis. Thus, a FeNi alloy uniformly embedded in 3D nitrogen-doped porous carbon materials (FeNi@NC) was constructed in the subsequent pyrolysis process and used as an efficient bifunctional oxygen reduction/evolution (ORR/OER) electrocatalyst for rechargeable ZABs. Impressively, the FeNi@NC catalyst carries high half-wave potential (0.850 V) in ORR and the low overpotential (291 mV) in OER, significantly better than Pt/C (0.830 V) and RuO2 (307 mV), respectively. In addition, the rechargeable ZAB assembled with FeNi@NC air cathode has a specific capacity of 649 mW cm−2 and shows no significant degradation after 240 h of charging and discharging cycles. This study provides a new design idea for the manufacture of carbon-supported non-noble metal alloy catalysts with bifunctional oxygen catalytic activity, and verifies the feasibility of regulating the composition of non-noble metals to construct a rechargeable ZABs with excellent performance.

Surfactant-assisted synthesis of NiCo alloy with specific nanopore architecture as a bifunctional electrocatalyst for rechargeable zinc-air batteries

Designing the effective active sites and reaction areas of catalytic materials is important for the development of bifunctional electrocatalysts for zinc-air batteries (ZABs). In this paper, a catalyst with a uniform nanopore structure (noted as NiCo-PS) was one-pot synthesized by using transition metals nickel and cobalt as catalytic active components, sucrose as a carbon source, and triblock copolymers as a soft template. The N2 absorption and desorption isotherms curves show that the pore size distribution of NiCo-PS modified by surfactant is mainly in 3.6 nm range. NiCo-PS exhibits exceptional bifunctional electrocatalysis due to its effective triple-phase reaction interface from its mesoporous structure, with a positive half-wave potential of 0.758 V for ORR and a low overpotential of 390 mV at 10 mA ⋅ [Formula: see text] for OER. Furthermore, the rechargeable ZABs with the NiCo-PS catalyst exhibit a high open-circuit voltage of 1.31 V, a significant peak power density of 105 mA ⋅ [Formula: see text] at 0.56 V, and good stability throughout 270 h testing. This result offers valuable insights for designing catalysts that enhance the active region of the reaction within the cathodes of ZABs and hold significant promise for practical applications.

Multidimensional bimetallic-codoped MOF-derived M@N-CNTs bifunctional electrocatalysts for rechargeable zinc-air batteries

Multidimensional bimetallic-codoped MOF-derived M@N-CNTs bifunctional electrocatalysts for rechargeable zinc-air batteries

Highly Efficient Oxygen Electrocatalyst for Rechargeable Zinc-Air Batteries: Surface-Oxidized Cobaltous Fluoride Nanocrystals Embedded in Carbon Nanofibers

Highly Efficient Oxygen Electrocatalyst for Rechargeable Zinc-Air Batteries: Surface-Oxidized Cobaltous Fluoride Nanocrystals Embedded in Carbon Nanofibers

External Field-Responsive Ternary Non-Noble Metal Oxygen Electrocatalyst for Rechargeable Zinc-Air Batteries.

Despite the increasing effort in advancing oxygen electrocatalysts for zinc-air batteries (ZABs), the performance development gradually reaches a plateau via only ameliorating the electrocatalyst materials. Herein, a new class of external field-responsive electrocatalyst comprising Ni0.5Mn0.5Fe2O4 stably dispersed on N-doped Ketjenblack (Ni0.5Mn0.5Fe2O4/N-KB) is developed via polymer-assisted strategy for practical ZABs. Briefly, the activity indicator ΔE is significantly decreased to 0.618V upon photothermal assistance, far exceeding most reported electrocatalysts (generally >0.680V). As a result, the photothermal electrocatalyst possesses comprehensive merits of excellent power density (319mW cm-2), ultralong lifespan (5163 cycles at 25mA cm-2), and outstanding rate performance (100mA cm-2) for liquid ZABs, and superb temperature and deformation adaptability for flexible ZABs. Such improvement is attributed to the photothermal-heating-enabled synergy of promoted electrical conductivity, reactant-molecule motion, active area, and surface reconstruction, as revealed by operando Raman and simulation. The findings open vast possibilities toward more-energy-efficient energy applications.

CoFe formic-acid framework derived S, N co-doped carbon nanotube composites decorated with a bimetallic sulfide as a bifunctional electrocatalyst for rechargeable zinc–air batteries

A S, N co-doped carbon nanotube ORR/OER electrocatalyst loaded with a cobalt–iron alloy and Co8FeS8 nanoparticles was synthesized using a one-step pyrolysis method.

Hierarchical porous Fe/Ni-based bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries

Developing sustainable and efficient bifunctional catalysts for oxygen reduction (ORR) and evolution (OER) reactions is challenging for energy conversion and storage. This work proposes a hierarchical carbon matrix decorated with nitrogen atoms (NC) as a support for obtaining high-performance electrocatalysts based on iron and nickel (Fe/Ni@N–C). The effect of different Fe:Ni ratios and the pyrolysis conditions on the catalyst performance were investigated by combining electrochemical tests, N2-adsorption-desorption, X-ray diffraction, Transmission Electron Microscopy, and X-ray photoelectron spectroscopy. Once optimized the pyrolysis conditions and the Fe:Ni ratio, the Fe/Ni@N–C catalyst showed high bifunctional OER/ORR activity in a three-electrode cell in an alkaline environment (KOH 1 M), with an overall ΔE for the ORR-OER reaction of 0.75 V. Fe/Ni@N–C was assembled in a rechargeable zinc-air battery, resulting in an excellent electrochemical performance in terms of power density (148.5 mWcm−2) and durability, outperforming the benchmark Pt/C–RuO2.

Facile hydrothermal synthesis of NiMoO4·xH2O nanorods-like structures as bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries

Developing highly active and low-cost bifunctional catalyst materials to replace precious metal species is of utmost importance for the commercialization of clean and sustainable energy systems. In this report, homogenous NiMoO4·xH2O nanorods (NRs)-like structured materials were synthesized by an annealing-free hydrothermal method. The synthesized electrode electrochemical properties were determined by linear sweep voltammetry using a rotating ring disk electrode to determine the characteristics of oxygen reduction reaction in an O2-saturated electrolyte solution. For the oxygen evolution reaction, the NiMoO4·xH2O NRs electrocatalyst showed lower overpotential of 185 mV to obtain 10 mA cm−2. Furthermore, the NiMoO4·xH2O NRs electrocatalyst-based zinc (Zn)-air battery exhibited lower voltage gaps and smaller electrochemical impedance spectroscopy values than the Pt/C catalyst. Importantly, the NiMoO4·xH2O NRs-based battery (60 cycles (∼1100 min)) revealed excellent cycling stability results when compared with the Pt/C-based battery (30 cycles (∼550 min)). The NR structured electrode provided good steady potential after being subjected to a fixed current density of 10 mA cm−2 for 100 h. Therefore, these results demonstrate that the synthesized NiMoO4·xH2O NRs material is promising as a bifunctional electrocatalyst for rechargeable Zn-air batteries.

Nickel-iron layered double hydroxides interlinked by N-doped carbon network as bifunctional electrocatalysts for rechargeable zinc-air batteries

The rational design and fabrication of electrocatalysts with low cost and excellent bifunctional properties for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are desirable for high-efficiency rechargeable zinc-air batteries. Herein, we report the synthesis of NiFe LDHs nanoparticles interconnected by the one-dimensional N-doped carbon nanotubes (CNTs) and two-dimensional graphene nanosheets (NiFe-CNTs-rGO). The in-situ formed N-doped carbon and Fe-N-C active sites highly improve the ORR activity and the loading of NiFe LDHs nanoparticles promotes the OER. The integration of NiFe LDHs with intertwined CNTs and netlike rGO guarantees the good electrical conductivity of NiFe-CNTs-rGO. The unique composition and microstructure endow NiFe-CNTs-rGO with superior bifunctional activity toward ORR and OER. Moreover, the rechargeable zinc-air battery assembled with NiFe-CNTs-rGO electrocatalyst as air cathode shows a high capacity of 793 mA h g−1 and works stable for 100 h at 10 mA cm−2, outperforming commercial Pt/C and RuO2 mixture.

Accelerated deprotonation with a hydroxy-silicon alkali solid for rechargeable zinc-air batteries

Transition metal oxides are promising electrocatalysts for zinc-air batteries, yet surface reconstruction caused by the adsorbate evolution mechanism, which induces zinc-ion battery behavior in the oxygen evolution reaction, leads to poor cycling performance. In this study, we propose a lattice oxygen mechanism involving proton acceptors to overcome the poor performance of the battery in the OER process. We introduce a stable solid base, hydroxy BaCaSiO4, onto the surfaces of PrBa0.5Ca0.5Co2O5+δ perovskite nanofibers with a one-step exsolution strategy. The HO-Si sites on the hydroxy BaCaSiO4 significantly accelerate proton transfer from the OH* adsorbed on PrBa0.5Ca0.5Co2O5+δ during the OER process. As a proof of concept, a rechargeable zinc-air battery assembled with this composite electrocatalyst is stable in an alkaline environment for over 150 hours at 5 mA cm–2 during galvanostatic charge/discharge tests. Our findings open new avenues for designing efficient OER electrocatalysts for rechargeable zinc-air batteries.

In situ growth of surface-reconstructed aluminum fluoride nanoparticles on N, F codoped hierarchical porous carbon nanofibers as efficient ORR/OER bifunctional electrocatalysts for rechargeable zinc-air batteries

Modified porous carbon fibers have emerged as crucial electrocatalytic materials for zinc-air battery (ZAB) systems. However, most methods for preparing porous carbon fibers are complex and exhibit single functionality and poor catalytic activity, which hinders the development of ZABs. In this study, we design and synthesize a novel type of N, F codoped hierarchical porous carbon fiber with in situ growth of aluminum fluoride nanoparticles (AlF3@HPCNFs) through electrospinning and high-temperature carbonization. The N, F codoping effectively adjusts the charge density of neighboring carbon atoms and introduces additional active sites. Furthermore, the catalytic process induces surface reconstruction of AlF3 nanoparticles, allowing for their full exposure to the liquid electrolyte and accelerated catalytic reactions. Additionally, this interconnected hierarchical porous structure accelerates mass transfer at the oxygen/carbon-based substrate/electrolyte three-phase interfaces, thereby enhancing reaction kinetics and the accessibility of catalytic active sites, ultimately improving the utilization efficiency of these sites. Consequently, the AlF3@HPCNFs catalyst exhibits excellent bifunctional performance with a narrow potential difference (△E = 0.67 V). Moreover, the obtained bifunctional electrocatalyst is utilized for rechargeable ZABs, surpassing commercially available Pt/C + RuO2 cells in terms of high specific capacity (796 mAh gzn−1) and outstanding cycling stability (over 500 h). This research demonstrates the potential of AlF3@HPCNFs as a bifunctional electrocatalyst and introduces a simplified and effective method for the fabrication of metal fluoride-modified and hierarchically porous carbon nanofibers for rechargeable ZABs.

Cobalt oxide nanosheets anchored on loofah sponge-derived carbon as a high-performance bifunctional electrocatalyst for rechargeable zinc-air batteries

Rechargeable zinc-air batteries need bifunctional electrocatalysts to improve the kinetics of both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Herein, we prepare a CoO@NC catalyst employing the 'carbonization-solvothermal-calcination' method, which involves affixing CoO nanosheets to the nitrogen-doped carbon matrix derived from the loofah sponge. The synergy of NC and CoO components creates abundant active sites, and their hierarchical porous structure enables the swift movement of relevant species, thus allowing the CoO@NC catalyst to display remarkable bifunctional performance with a potential difference of 0.73 V. Additionally, the CoO@NC-driven zinc-air battery exhibits a remarkable peak power density of 112.4 mW cm−2 and works reliably for more than 200 h, outperforming the commercial Pt/C-RuO2 catalysts. This research proposes a novel strategy for constructing noble-metal-free bifunctional electrocatalysts.

Highly active CoP embedded in hollow nitrogen-doped carbon as an efficient bifunctional electrocatalyst for rechargeable zinc-air batteries

Aqueous zinc-air batteries provide a possibility to replace fossil fuels. However, developing bi-functional electrocatalysts with high activity, low-cost and environmental friendliness for zinc-air batteries remains a challenge. In this work, we report an efficient bifunctional electrocatalyst (H–CoP@NC) that is fabricated by phosphating a hollow metal organic framework (MOF) prepared using a self-template method. The H–CoP@NC exhibits a half-wave potential of 0.81V (vs. RHE) for the oxygen reduction reaction (ORR), and an overpotential of 390 mV for the oxygen evolution reaction (OER) at a current density of 10 mA cm−2. Remarkably, the H–CoP@NC assembled zinc-air battery possesses a voltage gap of 0.82 V at a current density of 50 mA cm−2, and the voltage gap increases by only 0.01 V after 730 continuous charge and discharge cycles. This excellent electrocatalytic activity for ORR and OER can be attributed to the hollow structure, which improves mass transport during the electrocatalytic reaction, and the synergistic effect between CoP and heteroatom doped carbon skeletons which provide a high density of exposed active sites.

Cobalt Phthalocyanine-Doped Polymer-Based Electrocatalyst for Rechargeable Zinc-Air Batteries.

Rechargeable zinc-air batteries (RZAB) have gained significant attention as potential energy storage devices due to their high energy density, cost-effectiveness, and to the fact that they are environmentally safe. However, the practical implementation of RZABs has been impeded by challenges such as sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), including poor cyclability. Herein, we report the preparation of cobalt- and nitrogen-doped porous carbon derived from phloroglucinol-formaldehyde polymer networks with 2-methyl imidazole and cobalt phthalocyanine as precursors for nitrogen and cobalt. The CoN-PC-2 catalyst prepared in this study exhibits commendable electrocatalytic activity for both ORR and OER, evidenced by a half-wave potential of 0.81 V and Ej=10 of 1.70 V. Moreover, the catalyst demonstrates outstanding performance in zinc-air batteries, achieving a peak power density of 158 mW cm-2 and displaying excellent stability during charge-discharge cycles. The findings from this study aim to provide valuable insights and guidelines for further research and the development of hierarchical micro-mesoporous carbon materials from polymer networks, facilitating their potential commercialisation and widespread deployment in energy storage applications.

Electrocatalysts for Zinc-Air Batteries Featuring Single Molybdenum Atoms in a Nitrogen-Doped Carbon Framework.

Bifunctional catalysts can facilitate two different electrochemical reactions with conflicting characteristics. Here, a highly reversible bifunctional electrocatalyst for rechargeable zinc-air batteries (ZABs) is reported featuring a "core-shell structure" in which N-doped graphene sheets wrap around vanadium molybdenum oxynitride nanoparticles. Single Mo atoms are released from the particle core during synthesis and anchored to electronegative N-dopant species in the graphitic shell. The resultant Mo single-atom catalysts excel as active oxygen evolution reaction (OER) sites in pyrrolic-N and as active oxygen reduction reaction (ORR) sites in pyridinic-N environments. ZABs with such bifunctional and multicomponent single-atom catalysts deliver high power density (≈376.4mWcm-2 ) and long cycle life of over 630h, outperforming noble-metal-based benchmarks. Flexible ZABs that can tolerate a wide range of temperatures (-20 to 80°C) under severe mechanical deformation are also demonstrated.

Emerging high-entropy materials as electrocatalysts for rechargeable zinc–air batteries

The need for electrocatalysts that possess multiple surface sites to facilitate *O, *OH and *OOH intermediates in the complex reactions steps of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) has led to the emergence of the high-entropy materials (HEMs) as promising bifunctional electrocatalysts for rechargeable zinc-air batteries (RZABs). This mini-review presents inherent physico-chemical properties of HEMs that have endowed great interest as electrocatalysts for RZABs. Although the HEMs exhibit excellent electrocatalysis, to date, none of them (just like the conventional catalysts) has achieved the nominal voltage of 1.66 V for RZAB. Thus, in our opinion, effort should be devoted to the design engineering and fabrication to mitigate this key disadvantage.

Corrigendum to “Ball mill-assisted synthesis of NiFeCo-NC as bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries” [J. Alloy. Compd. 922 (2022) 166287

Corrigendum to “Ball mill-assisted synthesis of NiFeCo-NC as bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries” [J. Alloy. Compd. 922 (2022) 166287

Copper nanodot-embedded nitrogen and fluorine co-doped porous carbon nanofibers as advanced electrocatalysts for rechargeable zinc-air batteries

Porous carbon-based electrocatalysts for cathodes in zinc-air batteries (ZABs) are limited by their low catalytic activity and poor electronic conductivity, making it difficult for them to be quickly commercialized. To solve these problems of ZABs, copper nanodot-embedded N, F co-doped porous carbon nanofibers (CuNDs@NFPCNFs) are prepared to enhance the electronic conductivity and catalytic activity in this study. The CuNDs@NFPCNFs exhibit excellent oxygen reduction reaction (ORR) performance based on experimental and density functional theory (DFT) simulation results. The copper nanodots (CuNDs) and N, F co-doped carbon nanofibers (NFPCNFs) synergistically enhance the electrocatalytic activity. The CuNDs in the NFPCNFs also enhance the electronic conductivity to facilitate electron transfer during the ORR. The open porous structure of the NFPCNFs promotes the fast diffusion of dissolved oxygen and the formation of abundant gas-liquid-solid interfaces, leading to enhanced ORR activity. Finally, the CuNDs@NFPCNFs show excellent ORR performance, maintaining 92.5% of the catalytic activity after a long-term ORR test of 20000 s. The CuNDs@NFPCNFs also demonstrate super stable charge-discharge cycling for over 400 h, a high specific capacity of 771.3 mAh g−1 and an excellent power density of 204.9 mW cm−2 as a cathode electrode in ZABs. This work is expected to provide reference and guidance for research on the mechanism of action of metal nanodot-enhanced carbon materials for ORR electrocatalyst design.

Graphene-supported Fe/Ni single atoms and FeNi alloy nanoparticles as bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries

The development of inexpensive and high-performance bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of crucial significance for rechargeable metal-air batteries, but remains challenging. Herein, we report an ingenious bifunctional oxygen electrocatalyst integrating ZIF-derived carbon-anchored Fe/Ni single atoms, FeNi alloy nanoparticles, and graphene support (denoted as Fe/Ni-NC||FeNi@G). Synergizing highly active Fe single atoms for the ORR and highly efficient FeNi alloy nanoparticles for the OER, the as-constructed Fe/Ni-NC||FeNi@G catalyst exhibits outstanding bifunctionality; the potential gap between the OER potential at 10 mA cm–2 and the ORR half-wave potential is only 0.618 V, outperforming the benchmark Pt/C + Ir/C catalyst and most transition metal-based bifunctional catalysts reported in the literature. More importantly, the Fe/Ni-NC||FeNi@G-driven zinc-air battery (ZAB) delivers a maximum power density of ∼200 mW cm–2, a specific capacity of 876 mAh g–1, and excellent cycling stability with negligible voltage decay up to 500 hours (3000 cycles). This work provides an effective approach to designing highly efficient non-noble metal multifunctional catalysts for practical applications in rechargeable metal-air batteries.