Efficient Bifunctional Electrocatalysts Research Articles

S-doped g-C3N4 on Co/Ni metal-organic framework as efficient bifunctional electrocatalyst for in-situ hydrogen production from high-salt wastewater

An efficient and stable catalyst is the key to electrocatalytic hydrogen production. Herein, a bifunctional electrocatalyst is developed for electrocatalytic hydrogen production by depositing S-doped g-C3N4 on Co/Ni metal-organic framework electrode (namely CoNi-MOFs/S-g-C3N4). Compared with the original Co/Ni metal-organic framework (CoNi-MOFs), the overpotential of hydrogen production on CoNi-MOFs/S-g-C3N4 is reduced by 49.5 %, the charge transfer resistance is reduced by 74.5 %, and the electrochemically active area is expanded by 60.1 times. Moreover, CoNi-MOFs/S-g-C3N4 can be used as an efficient bifunctional electrocatalyst for overall water splitting. Impressively, using CoNi-MOFs/S-g-C3N4 as the anode and cathode, the hydrogen yield can reach 5.513 mmol h−1 and the energy consumption is 5.822 kWh Nm−3 at a current density of 250 mA cm−2. In addition, an in-situ overall water splitting system was designed for hydrogen production using high-salt wastewater as water source without additional pre-desalination process, which realizes green hydrogen production and reduces the cost. The hydrogen yield was hold in the range of 5.2–5.3 mmol h−1 for a week, showing excellent performance of hydrogen production and strong stability. More importantly, the system can be applied to various high-salt wastewater with wider pH and salinity, and shows promising application potential for hydrogen production in actual wastewater.

Vanadium-Doped Heterogeneous Bimetallic Phosphides Derived from Layered Double Hydroxides for Saline Water Splitting.

The development of energy- and time-saving synthetic methods to prepare bifunctional and high stability catalysts are vital for overall water splitting. Here, V-doped nickel-iron hydroxide precursor by etching NiFe foam (NFF) at room temperature with dual chloride solution ("NaCl-VCl3"), is obtained then phosphating to obtain V-Ni2P-FeP/NFF as efficient bifunctional (oxygen/hydrogen exchange reaction, OER/HER) electrocatalysts, denoted as NFF(V, Na)-P. The NFF(V, Na)-P requires only 185 and 117 mV overpotentials to reach 10 mA cm-2 for OER and HER. When used as a catalyst for water splitting in a full cell, it can be stably sustained for more than 1000 h in alkaline brine electrolysis at both current densities of 100 and 500 mA cm-2. In situ Raman analyses and density functional theory (DFT) show that the V-doping-induced surface remodeling generates hydroxyl oxides as the true catalytic active centers, which not only enhances the reaction kinetics, but also reduces the free energy change in the rate-determining step. This work provides a cost-effective substrate self-derivation method to convert commercial NFF into a powerful catalyst for electrolytic brine, offering a unique route to the development of efficient electrocatalysts for saline water splitting.

Bimetallic Ni–Fe nanoparticles encapsulated with biomass-derived N-doped graphitic carbon core-shell nanostructures an efficient bifunctional electrocatalyst for enhanced overall seawater splitting and human urine electrolysis

Producing green hydrogen from abundant natural resources such as seawater and human urine is a viable solution for energy and industrial applications. However, the field of electrocatalysis faces challenges in developing cost-effective metal catalysts for efficient electrolysis of seawater and urea sewage. Here, we reported bimetallic NiFe nanoparticles encapsulated in a biomass derived N-doped graphitic carbon core shell structure (NiFe@BNGC-700) as a stable and effective catalyst for seawater and human urine electrolysis. NiFe@BNGC-700 exhibits remarkable electrocatalytic performance, with a low overpotential requiring 300 mV for OER and 297 mV for HER in alkaline 1.0 M KOH + seawater and 1.36 V for UOR in alkaline 1.0 M KOH + human urine at 50 mA cm−2 current density, respectively. The active bifunctional NiFe@BNGC-700 electrocatalyst symmetry pair facilitates the construction of a seawater electrolyser, achieving a cell voltage of 1.74 V at 50 mA cm−2 current density. Furthermore, the human urine-mediated electrolyser employing NiFe@BNGC-700//NiFe@BNGC-700 achieves a cell voltage of 1.64 V at the same current density, maintaining stability over 12 h with negligible potential deviation. Continual evolution of hydrogen and oxygen is feasible in a solar seawater a cell assembled with NiFe@BNGC-700 electrocatalyst, delivering at cell voltage of 1.74 V, enabling sustained and effective green hydrogen delivery on a large scale. This study proposes a sustainable strategy for fabricating electrodes consisting of non-precious metals, thereby permitting the economical and extensive generation of green hydrogen on a large scale.

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.

In-situ stabilization of metal-nitride sites in sprouted 2D cMOF@LDHs hetero-nano petals on metaloxynitrides nanostems for enhanced water splitting

Addressing the challenges of enhancing water-splitting efficiency necessitates the exploration and rational design of high-performance and durable electrocatalysts with appealing nanoarchitectures. In this study, we present the design and fabrication of conjugated cMOF/LDH hetero-nano petals decorated with monodispersed Metal-N sites, which are uniformly shelled over tungsten oxynitride (WNO) nanowire arrays to form a unique core–shell architecture. For this rational engineering, WNO nanowire arrays were grown on carbon cloth. Then, a thin-layered Ru-Co-Fe layered double hydroxide (RuCoFe/LDH) was deposited around these wires, resulting in a highly porous three-dimensional array of hierarchical hetero RuCoFe-LDHs@WNO-NWs core–shell nanowires (RuCoFe-NSs@WNO-NWs). Subsequently, the linkers coordinated with the RuCoFe-LDH nanosheets and transformed them in-situ into the RuCoFe-cMOF nano petals (RuCoFe-NPs@WNO-NWs). Notably, the linker’s amino groups functioned as hooks for precisely anchoring and stabilizing metal sites, forming the metal nitride (M-N) moieties. Interestingly, the designed bi-functional catalyst exhibited superior catalytic activities for both OER (230 mV @ 10 mAcm−2) and HER (49 mV @ 10 mAcm−2) in an alkaline medium. Additionally, an electrolyzer cell employing Ru-CoFe-NPs@WNO-NWs as a bi-functional electrocatalyst required 1.49V to reach a current density of 10 mA cm−2. These remarkable catalytic performances can be attributed to several key factors, including opulent exposed active sites, an efficient charge/mass transport pathway, an optimized electronic structure, and an interfacial synergy effect. Hence, this study provides a new perspective for the design of efficient bi-functional electrocatalysts for use in the energy related electrochemical devices.

Guanine-derived core-shell FeCo alloy confined in graphene-like N-doped carbon as efficient bifunctional oxygen electrocatalysts for rechargeable Zn-air batteries

Maximization the synergistic effect of each component in transition metal-carbon complexes is expected to improve the bifunctional oxygen electrocatalysis for rechargeable Zn-air batteries but is still challenging. Herein, nucleobase guanine is employed as a supramolecular precursor to generate the core (FeCo alloy)-shell (carbon) structure embedded in ultrathin graphene-like nitrogen-doped carbon nanosheets (FeCo@NCNSs) via a confinement pyrolysis strategy. Thanks to the generated core-shell structure and bimetallic synergistic effect, the as-prepared FeCo@NCNSs exhibits excellent electrochemical performance in both oxygen reduction reaction and oxygen evolution reaction. As a result, when served as the bifunctional air electrode for a practical Zn-air battery, FeCo@NCNSs exhibits a higher open-circuit voltage (1.553 V) and peak power density (197.30 mW cm−2), as well as the greatly improved long-term cyclic stability compared to the noble metal benchmarks. This work provides a promising approach to integrate various active sites for bifunctional oxygen electrocatalysis and inspires the exploration of simple but efficient electrocatalysts for energy storage and conversion.

Construction of structurally engineered NiCo2O4 nanostructures as a bifunctional electrocatalyst for high-performance overall water splitting

The development of low-cost and highly efficient bifunctional electrocatalysts for overall water splitting is a challenging but urgent goal. Herein, nickel cobaltite (NiCo2O4) with different morphologies was developed for electrocatalytic overall water splitting. Encouragingly, the NiCo2O4 nanoneedle arrays required competitive hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) overpotentials of 106 and 310 mV to achieve a density of 10 mA cm−2 (j10) in KOH media, respectively. Furthermore, the as-made nanoneedle electrocatalyst employed as both anode and cathode, which displayed a low voltage of 1.67 Vto attain j10, with satisfactory durability for 50 h. The nanoneedle morphology not only improves the electrochemical active surface area, but also helpful to boost the charge transfer ability of NiCo2O4 and control the adsorption of reaction intermediates in water splitting. These results demonstrate the feasibility of the NiCo2O4 nanostructure by altering the active sites using morphology to develop the electrocatalytic activity of the materials.

Defect-rich CoRu alloy embedded in the porous carbon serving as highly-efficient and bifunctional electrocatalyst for overall water splitting over a wide pH range

Exploring highly-efficient and pH-universal overall water splitting electrocatalysts are critical but keep challenging. Herein, a highly-efficient, dual-function and pH-universal electrocatalyst consisting of CoRu alloy nanoparticles embedded in the carbon matrix (CoRu/C) was successfully synthesized through an acid etching-pyrolysis conversion process using ZIF-67 as a precursor. Benefiting from the rich crystal defects created during the alloy formation process that could serve as active catalytic sites and the optimized electronic structure, the as-obtained CoRu/C electrocatalyst required overpotentials of only 18 and 37 mV to reach a current density of 10 mA cm−2 for hydrogen evolution reaction (HER) and 184 and 170 mV for oxygen evolution reaction (OER) in 1.0 M KOH and 0.5 M H2SO4 aqueous solution, respectively. For practical application, the CoRu/C catalyst only needs a cell voltage of 1.49 and 1.45 V in a two-electrode overall water splitting system to achieve a current density of 10 mA cm−2 in alkaline and acidic medium, respectively. The present work paves a new way for the design and construction of efficient bifunctional electrocatalyst for overall water splitting, and would inspire widespread research interest in the field of energy storage and conversion.

General and Facile Synthesis of Co/CoO Nanoparticals Supported by Nitrogen-Doped Graphenic Networks as Efficient Oxygen Electrocatalyst for Zn-Air Batteries.

Reasonable design of low-cost, high-efficiency and stable bifunctional oxygen electrocatalysts is of great significance to improve the reaction efficiency of Zn-air batteries, which is still a huge challenge. Here, we report a highly efficient bifunctional oxygen electrocatalyst with three-dimensional (3D) N-doped graphene network-supported cobalt and cobalt oxide nanoparticles (Co/CoO-NG), which can be in situ synthesized by inducing metal ions on metal plates via graphene oxide as an inducer. This 3D network structure and open active center show excellent bifunctional oxygen electrocatalytic activity under alkaline conditions, and can be used as an air electrode in rechargeable Zn-air batteries, with significantly better power density (244.28 mW cm-2) and stability (over 340 h) than commercial Pt/C+RuO2 mixtures. This work is conducive to advancing the practical application of graphene-based materials as air electrodes for rechargeable zinc-air batteries.

Exploring Flower-Structured Bifunctional VCu Layered Double Hydroxide and its Nanohybrid with g-C3N4for Electrochemical and Photoelectrochemical Seawater Electrolysis.

Seawater electrolysis holds great promise for sustainable green hydrogen generation, but its implementation is hindered by high energy consumption and electrode degradation. Two dimensional (2D) layered double hydroxide (LDH) exhibits remarkable stability, high catalytic activity, and excellent corrosion resistance in the harsh electrolytic environment. The synergistic effect between LDH and seawater ions enhances the oxygen evolution reaction, enabling efficient and sustainable green hydrogen generation. Here, we report a synthesis of low cost, novel 2D Vanadium Copper (VCu) LDH first time in the series of LDH's as a highly efficient bifunctional electrocatalyst. The electrochemical (EC) and photoelectrochemical (PEC) study of VCu LDH and VCu LDH/Graphite Carbon Nitride (g-C3N4) nanohybrid was performed in 0.5 M H2SO4 (acidic), 1 M KOH (basic), 0.5 M NaCl (artificial seawater), 0.5 M NaCl + 1 M KOH (artificial alkaline seawater), real seawater and 1 M KOH + real seawater (alkaline real seawater) electrolyte medium. It was found that VCu LDH shows a remarkable lower overpotential of 72 mV hydrogen evolution reaction (HER) and 254 mV oxygen evolution reaction (OER) at current density of 10 mA/cm2 under alkaline real seawater electrolysis exhibiting bifunctional activity and also showing better stability.

Synergistic Ru/RuO2 heterojunctions stabilized by carbon coating as efficient and stable bifunctional electrocatalysts for acidic overall water splitting

Synergistic Ru/RuO2 heterojunctions stabilized by carbon coating as efficient and stable bifunctional electrocatalysts for acidic overall water splitting

Unique sandwich-cookie-like nanosheet array heterojunction bifunctional electrocatalyst towards efficient overall water/seawater splitting

Construction of multi-component heterostructures is an effective strategy for electrocatalysts to improve both the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) activity at the anode. Herein, an efficient bifunctional electrocatalyst towards overall water/seawater splitting (OW/SS) is reported with strategy of heterostructure construction (ruthenium/nickel phosphorus) on nickel hydroxide (Ni(OH)2). With the unique hydrolysis layer (Ni(OH)2), the processes of H2O hydrolysis and the adsorption/desorption of H*/O-containing intermediates (OH, O, OOH) were greatly boosted by Ru and P sites, which acted as the catalytic active centers of OER and HER, respectively. In addition, the electronic structure reconfiguration was realized through the strong interaction between multi-interfaces. For alkaline HER at the current density of 10 mA cm−2, the overpotential of Ru-P-Ni(OH)2/NF (denoted as RNPOH/NF) was 98 mV, whereas just 230 mV of overpotential was essential to stimulate alkaline OER at the current density of 20 mA cm−2. Specifically, as a bifunctional electrocatalyst towards overall water splitting, RNPOH/NF deserves cell voltages of 1.7/1.92 V and 1.75/1.94 V, respectively, to activate current densities of 50/100 mA cm−2 in alkaline water/seawater systems, together with a good durability of 12 h. This work contributes insights to the development of bifunctional electrocatalysts for overall water/seawater splitting.

Heterogeneous Ni-Boride/Phosphide Anchored Amorphous B-C Layer for Overall Water Electrocatalysis.

The rational design of efficient and economical bifunctional electrocatalysts remained a challenge for overall water electrolysis. In this work, the Ni-boride/ phosphide particles anchored amorphous B-doped carbon layer with hierarchical porous characteristics in Ni foam (Ni3P/Ni3B/B-C/NF) was fabricated for overall water splitting. The Boroncarbide (B4C) power was filled and fixed in the NF interspace through the electroplating and electroless plating, and then annealed in vacuum high temperature. The amorphous B-C layer derived from the B4 C not only speeded up the electron transport, but also cooperate with Ni-boride/phosphide to enhance the electrocatalytic activity for HER and OER synergistically. Furthermore, the hierarchical porous architecture of Ni3P/Ni3B/B-C/NF increased space utilization to load more active materials. The self-supported Ni3P/Ni3B/B-C/NF electrode possessed a low overpotential of 212 and 280 mV to deliver 100 mA cm-2 for HER and OER, respectively, and high stability for 48 h. In particular, the electrolyzer constituted with the Ni3P/Ni3B/B-C/NF bifunctional electrocatalyst only required a voltage of 1.59 V at 50 mA cm-2 for water electrocatalysis under alkaline medium, and demonstrated long-term stability for 48 h. This study provides a new technical path for the development of bifunctional of transition metal borides to promote the application of hydrogen production from water splitting.

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.

Phosphorus-doped nickel cobalt oxide (NiCo2O4) wrapped in 3D hierarchical hollow N-doped carbon nanoflowers as highly efficient bifunctional electrocatalysts for overall water splitting

Properly design and fabricate capable electrocatalysts with 3D hierarchical hollow framework to realize cost-effective and efficacious overall water splitting (OWS) are particularly meaningful for the large-scale arrangement of pivotal energy technology. In this study, P-doped NiCo2O4 nanoparticles encapsulated in N-doped carbon hierarchical hollow nanoflowers (P-NiCo2O4@NCHHNFs) were constructed using the hydrothermal-pyrolysis-phosphorization approach. This fascinating architecture can not merely serve as a conductive pathway for electron transfer, but at the same time effectively inhibited the aggregation and corrosion of the NiCo2O4 nanoparticles. Additionally, the P doping not only regulates electronic structure configuration to boost the intrinsic activity of the catalyst, but also enhance electrochemical surface areas to reveal more accessible active sites. Attributing to these characteristics, the as-prepared P-NiCo2O4@NCHHNFs exhibit preeminent electrocatalytic performance with low overpotentials of 283 mV and 162 mV for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) (at 10 mA cm−2), respectively. Specifically, by using the P-NiCo2O4@NCHHNFs as bifunctional catalysts, a low potential of 1.56 V (at 10 mA cm−2) is sufficient to drive overall water splitting with splendid durability. This study proposed an innovative strategy for the conceiving and fabricating high-performance catalysts via heteroatom-doping.

FeNi alloys incorporated N-doped carbon nanotubes as efficient bifunctional electrocatalyst with phase-dependent activity for oxygen and hydrogen evolution reactions

Electrochemical oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are two important half-cell reactions for overall water splitting. The rational design and fabrication of efficient electrocatalysts involving nonprecious-metals and carbon matrix is highly attractive. Herein, a series of N-doped carbon nanotubes encapsulated FeNi alloy nanoparticles (FeNi@NCNTs) are synthesized via a simple pyrolysis treatment of Fe-doped Ni(OH)2 precursors under the assistance of dicyandiamine source. The results reveal that the Fe/Ni ratio has an obvious influence on the morphology and phase composition of FeNi@NCNTs series, thus affecting the electrocatalytic performance. The highest electrocatalytic activity is achieved for the Fe1Ni4@NCNTs product with a Fe/Ni molar ratio of 1:4, which delivers low overpotentials of 278 and 279 mV for OER and HER at 10 mA cm−2 in 1.0 mol/L KOH, respectively. The intriguing electrocatalytic performance is mainly ascribed to the advantageous integration of rambutan-like hierarchically porous structure and composition optimization, significantly facilitating the fast mass/charge transfer as well as promoting the adsorption ability for intermediates. The present method may open a facile avenue for developing cost-effective, high-activity, and stable electrocatalysts for the application of overall water splitting.

Ni-Fe-P/Co-W: Nested heterostructures and multi-transition metal synergistic effect optimizing overall water splitting performance

Recently, the application of multi-component transition alloy catalysts in the water splitting field has been a popular development trend. In this work, we have proposed a multi-alloy catalyst for in-situ synthesis of nested multilayer heterostructure Co-W on Ni-Fe-P by electrodeposition way. The heterogeneous interfaces brought by the nested heterogenous structure expose abundant active sites on the catalyst, effectively enhancing the catalytic performance. Moreover, the synergistic effect of five elements (Ni, Fe, P, Co, and W) in the electrocatalysts improves electron transfer efficiently. By adjusting the proportion of Co and W of Co-W-O in the Ni-Fe-P plating solution, we have obtained optimal electrochemical performance in 1 M KOH solution. At 150 (10) mA cm−2, the HER and OER overpotentials are 157.6 (23.6) mV and 260.6 (219.9) mV respectively. Furthermore, it shows a low cell voltage (1.46 V) in overall water splitting, exceeding most of the previously reported electrocatalysts. The activity of Ni-Fe-P/Co-W has no significant decrease at 100 mA cm−2 for 100 h. Subsequently, XPS and Raman spectroscopy are used to infer the mechanism of the electrochemical reaction. This study demonstrates a kind of simple, scalable, and efficient bifunctional electrocatalyst method that has special nested heterogenous structure for overall water splitting.

γ-FeOOH Nanosheet with Enormous Cationic Defect: Efficient and Durable Bifunctional Electrocatalyst Suitable for an Industrial-Scale AEM Electrolyzer

γ-FeOOH Nanosheet with Enormous Cationic Defect: Efficient and Durable Bifunctional Electrocatalyst Suitable for an Industrial-Scale AEM Electrolyzer

Cobalt Phthalocyanine Based Metal–Organic Framework as an Efficient Bifunctional Electrocatalyst for Water Electrolysis

Cobalt Phthalocyanine Based Metal–Organic Framework as an Efficient Bifunctional Electrocatalyst for Water Electrolysis

S-doped NiCo layered double hydroxides enable efficient and durable methanol oxidation and oxygen reduction reactions for Zn-methanol-air batteries

The employment of alcohol oxidation reactions (AORs) is thermodynamically more favorable to replace the anodic oxygen evolution reaction (OER) in rechargeable Zn-air batteries (ZABs). As a representative AOR-coupled ZAB, Zn-methanol-air battery (ZMAB) gratifyingly delivers a lower charge voltage, higher energy efficiency, longer cycle life and more valuable charge product in comparison with the traditional ZAB. For such emerging ZMABs, it is imperative to explore efficient, stable and cost-effective bifunctional electrocatalysts for both methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). Herein, sulfur-doped NiCo layered double hydroxides (termed NiCo-LDH@SOH) are fabricated by a room-temperature surface sulfurization route. Remarkably, the NiCo-LDH@SOH heterostructure catalyst achieves a superb bifunctional activity for MOR and ORR, performing a low potential gap ΔE between the Ej10 for MOR and the half-wave potential E1/2 for ORR of only 0.596 V, far surpassing that (0.790 V) for Pt/C-IrO2 benchmark catalyst. The electronic interactions between S2− and transition metal ions significantly accelerate the charge transfer process and generate highly efficient Ni3+ and Co2+ active sites on NiCo-LDH@SOH, which account for the exceptional MOR and ORR performance, respectively. Thanks to the favorable replacement of OER with MOR and the excellent MOR/ORR bifunctional activity of NiCo-LDH@SOH, the ZMAB can output a comparable discharge power density (140 mW cm−2) to the traditional ZAB counterpart (149 mW cm−2), but a much lower charge voltage than the latter. In consequence, the ZMAB demonstrates an extraordinary long-term cyclability of 2880 cycles for 480 h (20 days) with almost no degradation, which is more than 5 times longer than that of the traditional ZAB.