Realizing ampere-level CO2 electrolysis at low voltage over a woven network of few-atom-layer ultralong silverene nanobelts with ultrahigh aspect ratio by pairing with formaldehyde oxidation.

The development of advanced multi-functional electrocatalysts and their industrial operation on paired electrocatalysis systems presents a promising avenue for the gradual penetration of renewable energy into practical production. Herein, a self-supported conductive network of silverene nanobelts (Ag-ene NBs) was delicately assembled (Ag-NB-NWs), in which ultralong and few-atom-layer Ag-ene NBs with a high edge-to-facet ratio were interconnected, serving as "superreactors" for electron transfer and mass transport during the reaction. Such superstructures as electrocatalysts delivered an unparalleled performance toward the CO2-to-CO conversion with exclusively high faradaic efficiency (FE) and partial current densities of up to 1 A cm-2. Remarkably, the membrane electrode assembly (MEA) cell with Ag-NB-NWs as the cathode was capable of ultrastable and continuous operation for over 240 h at 0.4 A with ∼100% selectivity. More importantly, by further using Ag-NB-NWs as a bifunctional electrocatalyst, a record-low voltage overall CO2 electrolysis system coupling cathodic CO2 reduction with anodic formaldehyde oxidation in MEA cell was performed to achieve concurrent feed gas generation and formate production, substantially improving electrochemical techno-economic feasibility.

Catalyzing Desolvation at Cathode-Electrolyte Interface Enabling High-Performance Magnesium-Ion Batteries.

Magnesium ion batteries (MIBs) are expected to be the promising candidates in the post-lithium-ion era with high safety, low cost and almost dendrite-free nature. However, the sluggish diffusion kinetics and strong solvation capability of the strongly polarized Mg2+ are seriously limiting the specific capacity and lifespan of MIBs. In this work, catalytic desolvation is introduced into MIBs for the first time by modifying vanadium pentoxide (V2 O5 ) with molybdenum disulfide quantum dots (MQDs), and it is demonstrated via density function theory (DFT) calculations that MQDs can effectively lower the desolvation energy barrier of Mg2+ , and therefore catalyze the dissociation of Mg2+ -1,2-Dimethoxyethane (Mg2+ -DME) bonds and release free electrolyte cations, finally contributing to a fast diffusion kinetics within the cathode. Meanwhile, the local interlayer expansion can also increase the layer spacing of V2 O5 and speed up the magnesiation/demagnesiation kinetics. Benefiting from the structural configuration, MIBs exhibit superb reversible capacity (≈300 mAh g-1 at 50 mA g-1 ) and unparalleled cycling stability (15 000 cycles at 2 A g-1 with a capacity of ≈70 mAh g-1 ). This approach based on catalytic reactions to regulate the desolvation behavior of the whole interface provides a new idea and reference for the development of high-performance MIBs.

Organic Molecular Intercalation Enabled Anionic Redox Chemistry with Fast Kinetics for High Performance Magnesium Storage.

Rechargeable magnesium-ion batteries possess desirable characteristics in large-scale energy storage applications. However, severe polarization, sluggish kinetics and structural instability caused by high charge density Mg2+ hinder the development of high-performance cathode materials. Herein, the anionic redox chemistry in VS4 is successfully activated by inducing cations reduction and introducing anionic vacancies via polyacrylonitrile (PAN) intercalation. Increased interlayer spacing and structural vacancies can promote the electrolyte ions migration and accelerate the reaction kinetics. Thanks to this "three birds with one stone" strategy, PAN intercalated VS4 exhibits an outstanding electrochemical performance: high discharge specific capacity of 187.2 mAh g-1 at 200 mA g-1 after stabilization and a long lifespan of 5000 cycles at 2 A g-1 are achieved, outperforming other reported VS4-based materials to date for magnesium storage under the APC electrolyte. Theoretical calculations confirm that the intercalated PAN can indeed induce cations reduction and generate anionic vacancies by promoting electron transfer, which can accelerate the electrochemical reaction kinetics and activate the anionic redox chemistry, thus improving the magnesium storage performance. This approach of organic molecular intercalation represents a promising guideline for electrode material design on the development of advanced multivalent-ion batteries.

Regulating cathode surface hydroxyl chemistry enables superior potassium storage.

Potassium vanadium fluorophosphate (KVPO4F) is regarded as a promising cathode candidate for potassium-ion batteries due to its high working voltage and satisfactory theoretical capacity. However, the usage of electrochemically inactive binders and redundant current collectors typically results in inferior electrochemical performance and low energy density, thus implying the important role of rational electrode structure design. Herein, we have reported a scalable and cost-effective synthesis of a cellulose-derived KVPO4F self-supporting electrode, which features a special surface hydroxyl chemistry, three-dimensional porous and conductive framework, as well as super flexible and stable architecture. The cellulose not only serves as a flexible substrate, a pore-forming agent, and a versatile binder for KVPO4F/conductive carbon but also enhances the K-ion migration ability. Benefiting from the special hydroxyl chemistry-induced storage mechanism and electrode structural stability, the flexible freestanding KVPO4F cathode exhibits high-rate performance (53.0% capacity retention with current densities increased 50-fold, from 0.2 C to 10 C) and impressive cycling stability (capacity retention up to 74.9% can be achieved over 1,000 cycles at a rate of 5 C). Such electrode design and surface engineering strategies, along with a deeper understanding of potassium storage mechanisms, provide invaluable guidance for better electrode design to boost the performance of potassium-ion energy storage systems.

Enabling Ultrafast Single Mg2+ Insertion Kinetics of Magnesium-Ion Batteries via In Situ Dynamic Catalysis and Re-equilibration Effects.

Magnesium-ion batteries (MIBs) have great potential in large-scale energy storage field with high capacity, excellent safety, and low cost. However, the strong solvation effect of Mg2+ will lead to the formation of solvated ions in electrolytes with larger size and sluggish diffusion/reaction kinetics. Here, the concept of interfacial catalytic bond breaking is first introduced into the cathode design of MIBs by hybriding MoS2 quantum dots with VS4 (VS4@MQDs) as the cathode. The "in situ dynamic catalysis and re-equilibration" effects can catalyze the Cl-Mg bond breaking and trigger single Mg2+ insertion/extraction chemistries, which can significantly accelerate the diffusion and reaction kinetics, as verified by the decreased diffusion energy barriers (0.26 eV for Mg2+ vs 2.47 eV for MgCl+) and fast diffusion coefficient. Benefitting from these dynamic catalysis effects, the constructed VS4@MQD-based MIBs deliver a high discharge capacity of ∼120 mA h g-1 at 200 mA g-1 and a long-term cyclic stability of 1000 cycles at 1 A g-1. The improved performance and detailed characterizations well prove that the active ions in MIBs change from MgCl+/Mg2Cl3+ to Mg2+ with fast kinetics.

Liquid-Like Li-Ion Conduction in Oxides Enabling Anomalously Stable Charge Transport across the Li/Electrolyte Interface in All-Solid-State Batteries.

The softness of sulfur sublattice and rotational PS4 tetrahedra in thiophosphates result in liquid-like ionic conduction, leading to enhanced ionic conductivities and stable electrode/thiophosphate interfacial ionic transport. However, the existence of liquid-like ionic conduction in rigid oxides remains unclear, and modifications are deemed necessary to achieve stable Li/oxide solid electrolyte interfacial charge transport. In this study, by combining the neutron diffraction survey, geometrical analysis, bond valence site energy analysis, and ab initio molecular dynamics simulation, 1D liquid-like Li-ion conduction is discovered in LiTa2 PO8 and its derivatives, wherein Li-ion migration channels are connected by four- or five-fold oxygen-coordinated interstitial sites. This conduction features a low activation energy (0.2 eV) and short mean residence time (<1 ps) of Li ions on the interstitial sites, originating from the Li-O polyhedral distortion and Li-ion correlation, which are controlled by doping strategies. The liquid-like conduction enables a high ionic conductivity (1.2 mS cm-1 at 30 °C), and a 700 h anomalously stable cycling under 0.2 mA cm-2 for Li/LiTa2 PO8 /Li cells without interfacial modifications. These findings provide principles for the future discovery and design of improved solid electrolytes that do not require modifications to the Li/solid electrolyte interface to achieve stable ionic transport.

Building K-C Anode with Ultrahigh Self-Diffusion Coefficient for Solid State Potassium Metal Batteries Operating at -20 to 120 °C.

Solid state potassium (K) metal batteries are intriguing in grid-scale energy storage, benefiting from the low cost, safety, and high energy density. However, their practical applications are impeded by poor K/solid electrolyte (SE) interfacial contact and limited capacity caused by the low K self-diffusion coefficient, dendrite growth, and intrinsically low melting point/soft features of metallic K. Herein, a fused-modeling strategy using potassiophilic carbon allotropes molted with K is demonstrated that can enhance the electrochemical performance/stability of the system via promoting K diffusion kinetics (2.37 × 10-8 cm2 s-1 ), creating a low interfacial resistance (≈1.3 Ω cm2 ), suppressing dendrite growth, and maintaining mechanical/thermal stability at 200 °C. A homogeneous/stable K stripping/plating is consequently implemented with a high current density of 2.8 mA cm-2 (at 25 °C) and a record-high areal capacity of 11.86 mAh cm-2 (at 0.2 mA cm-2 ). The enhanced K diffusion kinetics contribute to sustaining intimate interfacial contact, stabilizing the stripping/plating at high current densities. Full cells coupling ultrathin K-C composite anodes (≈50 µm) with Prussian blue cathodes and ß/ß″-Al2 O3 SEs deliver a high energy density of 389 Wh kg-1 with a retention of 94.4% after 150 cycles and fantastic performances at -20 to 120 °C.

High-Performance Aqueous Zinc-Ion Batteries Enabled by Binder-Free and Ultrathin V2O5-x@Graphene Aerogels with Intercalation Pseudocapacitance.

As a result of the absence of solid-state diffusion limitation, intercalation pseudocapacitance behavior is emerging as an attractive charge-storage mechanism that can greatly facilitate the ion kinetics to boost the rate capability and cycle stability of batteries; however, related research in the field of zinc-ion batteries (ZIBs) is still in the initial stage and only found in limited cathode materials. In this study, a novel V2O5-x@rGO hybrid aerogel consisting of ultrathin V2O5 nanosheets (∼1.26 nm) with abundant oxygen vacancies (Vö) and a three-dimensional (3D) graphene conductive network was specifically designed and used as a freestanding and binder-free electrode for ZIBs. As expected, the ideal microstructure of both the material and the electrode enable fast electron/ion diffusion kinetics of the electrode, which realize a typical intercalation pseudocapacitance behavior as demonstrated by the simulation calculation of cyclic voltammetry (CV), ex situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and first-principles density functional theory (DFT) calculation. Thanks to the elimination of solid-state diffusion limitation, the V2O5-x@rGO electrode delivers a high reversible rate capacity of 153.9 mAh g-1 at 15 A g-1 and 90.6% initial capacity retention at 0.5 A g-1 after 1050 cycles in ZIBs. The intercalation pseudocapacitance behavior is also realized in the assembled soft-pack battery, showing promising practical application prospects.

High-Performance Composite Lithium Anodes Enabled by Electronic/Ionic Dual-Conductive Paths for Solid-State Li Metal Batteries.

Solid-state lithium metal batteries (SSLMBs) promise high energy density and high safety by employing high-capacity Li metal anode and solid-state electrolytes. However, the construction of the composite Li metal electrode is a neglected but important subject when the extensive research focuses on the interface between the solid electrolyte Li6.4 La3 Zr1.4 Ta0.6 O12 and Li metal anode. Here, an electronic-ionic conducting composite Li metal anode consisting of Li-Al alloy and LiF is constructed to achieve the stable electronic-ionic transport channel and the intimate interface contact, which can realize the uniform Li deposition and the efficiency utilization of lithium in composite Li metal electrode. Therefore, the symmetric battery with composite Li metal electrode exhibits the high critical current density with 1.2 mA cm-2 and stable cycle for 1500 h at 0.3 mA cm-2 , 25 °C. Moreover, the SSLMBs matched with LiFePO4 and LiNi0.8 Co0.1 Mn0.1 O2 achieve the outstanding electrochemical performance, verifying the feasibility of composite Li metal electrode in various SSLMBs systems.

Functionalized 12 µm Polyethylene Separator to Realize Dendrite-Free Lithium Deposition toward Highly Stable Lithium-Metal Batteries.

Direct application of metallic lithium (Li) as the anode in rechargeable lithium metal batteries (LMBs) is still hindered by some annoying issues such as lithium dendrites formation, low Coulombic efficiency, and safety concerns arising therefrom. Herein, an advanced composite separator is prepared by facilely blade coating lightweight and thin functional layers on commercial 12 µm polyethylene separator to stabilize the Li anode. The composite separator simultaneously improves the Li ion transport and lithium deposition behaviors with uniform lithium ion distribution properties, enabling the dendrite-free Li deposition. As a result, the lithium anode can stably cycle up to 3000 cycles with the high capacity of 3.5 mAh cm-2 . Moreover, the composite separator exhibits wide compatibility in LMBs (Li-S and Li-ion battery) and delivers stable cycling performance and high Coulombic efficiency both in coin and lab-level soft-pack cells. Thus, this cost-effective modification strategy exhibits great application potential in high-energy LMBs.

Correction: Engineering lithiophilic Ni-Al@LDH interlayers on a garnet-type electrolyte for solid-state lithium metal batteries.

Correction for 'Engineering lithiophilic Ni-Al@LDH interlayers on a garnet-type electrolyte for solid-state lithium metal batteries' by Wei Liu et al., Chem. Commun., 2021, 57, 10214-10217, DOI: 10.1039/D1CC02932K.

Engineering lithiophilic Ni-Al@LDH interlayers on a garnet-type electrolyte for solid-state lithium metal batteries.

In this work, a lithiophilic Ni-Al@LDH interlayer is engineered at the Li6.4La3Zr1.4Ta0.6O12 (LLZTO) electrolyte and Li anode interface. The Ni-Al@LDH interlayer can significantly reduce the interfacial resistance as well as give excellent cycling performance both in a symmetric Li//Li cell and solid full lithium metal batteries.

Universal lithiophilic interfacial layers towards dendrite-free lithium anodes for solid-state lithium-metal batteries.

Solid-state lithium-metal batteries (SSLMBs) using garnet Li6.4La3Zr1.4Ta0.6O12 (LLZTO) as the solid electrolyte are expected to conquer the safety concerns of high energy Li batteries with organic liquid electrolytes owing to its nonflammable nature and good mechanical strength. However, the poor interfacial contact between the Li anode and LLZTO greatly restrains the practical applications of the electrolyte, because large polarization, dendritic Li formation and penetration can occur at the interfaces. Here, an effective method is proposed to improve the wettability of the LLZTO toward lithium and reduce the interfacial resistance by engineering universal lithiophilic interfacial layers. Thanks to the in-situ formed lithiophilic and ionic conductive Co/Li2O interlayers, the symmetric Li/CoO-LLZTO/Li batteries present much smaller overpotential, ultra-low areal specific resistance (ASR, 12.3 Ω cm2), high critical current density (CCD, 1.1 mA cm-2), and outstanding cycling performance (1696 h at a current density of 0.3 mA cm-2) at 25 °C. Besides, the solid-state Li/CoO-LLZTO/LFP cells deliver an excellent electrochemical performance with a high coulombic efficiency of ~100% and a long cycling time over 185 times. Surprisingly, the high-voltage (4.6 V) solid state Li/CoO-LLZTO/Li1.4Mn0.6Ni0.2Co0.2O2.4 (LMNC622) batteries can also realize an ultra-high specific capacity (232.5 mAh g-1) under 0.1 C at 25 °C. This work paves an effective way for practical applications of the dendrite-free SSLMBs.

Origin of the electrocatalytic oxygen evolution activity of nickel phosphides: in-situ electrochemical oxidation and Cr doping to achieve high performance.

Zinc-air batteries (ZnABs) with high theoretical capacity and environmental benignity are the most promising candidates for next-generation electronics. However, their large-scale applications are greatly hindered due to the lack of high-efficient and cost-effective electrocatalysts. Transition metal phosphides (TMPs) have been reported as promising electrocatalysts. Notably, (Ni1-xCrx)2P (0 ≤ x ≤ 0.15) is an unstable electrocatalyst, which undergoes in-situ electrochemical oxidation during the initial oxygen evolution reaction (OER) and even in the activation cycles, and is eventually converted to Cr-NiOOH serving as the actual OER active sites with high efficiency. Density functional theory (DFT) simulations and experimental results elucidate that the OER performance could be significantly promoted by the synergistic effect of surface engineering and electronic modulations by Cr doping and in-situ phase transformation. The constructed rechargeable ZnABs could stably cycle for more than 208 h at 5 mA cm-2, while the voltage degradation is negligible. Furthermore, the developed catalytic materials could be assembled into flexible and all-solid-state ZnABs to power wearable electronics with high performance.

Graphene/Graphitized Polydopamine/Carbon Nanotube All-Carbon Ternary Composite Films with Improved Mechanical Properties and Through-Plane Thermal Conductivity.

Graphene films (GFs) are promising ultrathin thermally conductive materials for portable electronic devices because of their excellent thermally conductive property, light weight, high flexibility, and low cost. However, the application of GFs is limited due to their poor mechanical properties and through-plane thermal conductivity. Here, a graphene-(graphitized polydopamine)-(carbon nanotube) (G-gPDA-CNT) all-carbon ternary composite film was fabricated by chemical reduction, carbonization, graphitization, and mechanical compaction of the evaporation-assembled (graphene oxide)-PDA@CNT film. The G-gPDA-CNT film exhibited a uniform all-carbon composite structure in which the components of the graphene, gPDA layers, and CNTs were cross-linked by strong covalent bonds. This unique structure promoted the load transfer and energy dissipation between the components by which the mechanical properties of the G-gPDA-CNT film were substantially improved. Furthermore, electron and phonon transfers were also promoted, greatly improving the electrical and thermal conductivities, especially the through-plane thermal conductivity of the G-gPDA-CNT film. The G-gPDA-CNT film showed a tensile strength of 67.5 MPa, 15.1% ultimate tensile strain, toughness of 6.07 MJ/m3, electrical conductivity of 6.7 × 105 S·m-1, in-plane thermal conductivity of 1597 W·m-1·K-1, and through-plane thermal conductivity of 2.65 W·m-1·K-1, which were 2.24, 1.44, 3.16, 1.46, 1.15, and 3.90 times that of the pure GFs, respectively.

Hydroxyapatite Nanowire-Reinforced Poly(ethylene oxide)-Based Polymer Solid Electrolyte for Application in High-Temperature Lithium Batteries.

Hybrid polymer electrolytes with excellent performance at high temperatures are very promising for developing solid-state lithium batteries for high-temperature applications. Herein, we use a self-supporting hydroxyapatite (HAP) nanowire membrane as a filler to improve the performance of a poly(ethylene oxide) (PEO)-based solid-state electrolyte. The HAP membrane could comprehensively improve the properties of the hybrid polymer electrolyte, including the higher room-temperature ionic conductivity of 1.05 × 10-5 S cm-1, broad electrochemical windows of up to 5.9 V at 60 °C and 4.9 V at 160 °C, and a high lithium-ion migration of 0.69. In addition, the LiFePO4//Li full battery with a solid electrolyte possesses good rate capability, cycling, and Coulomb efficiency at extreme high temperatures, that is, after 300 continuous charge and discharge cycles at 4 C rate, the discharge capacity retention rate is 77% and the Coulomb efficiency is 99%. The use of the flexible self-supporting HAP nanowire membrane to improve the PEO-based solid composite electrolyte provides new strategies and opportunities for developing rechargeable lithium batteries in extreme high-temperature applications.

Ru Single Atoms on N-Doped Carbon by Spatial Confinement and Ionic Substitution Strategies for High-Performance Li-O2 Batteries.

Nonaqueous rechargeable lithium-oxygen batteries (LOBs) are one of the most promising candidates for future electric vehicles and wearable/flexible electronics. However, their development is severely hindered by the sluggish kinetics of the ORR and OER during the discharge and charge processes. Here, we employ MOF-assisted spatial confinement and ionic substitution strategies to synthesize Ru single atoms riveted with nitrogen-doped porous carbon (Ru SAs-NC) as the electrocatalytic material. By using the optimized Ru0.3 SAs-NC as electrocatalyst in the oxygen-breathing electrodes, the developed LOB can deliver the lowest overpotential of only 0.55 V at 0.02 mA cm-2. Moreover, in-situ DEMS results quantify that the e-/O2 ratio of LOBs in a full cycle is only 2.14, indicating a superior electrocatalytic performance in LOB applications. Theoretical calculations reveal that the Ru-N4 serves as the driving force center, and the amount of this configuration can significantly affect the internal affinity of intermediate species. The rate-limiting step of the ORR on the catalyst surface is the occurrence of 2e- reactions to generate Li2O2, while that of the OER pathway is the oxidation of Li2O2. This work broadens the field of vision for the design of single-site high-efficiency catalysts with maximum atomic utilization efficiency for LOBs.

1-Pyrenemethanol derived nanocrystal reinforced graphene films with high thermal conductivity and flexibility.

Miniaturization and integration of electronic components lead to increasing challenges of thermal management. Ultrathin materials with excellent thermal and flexibility are urgently required for portable electronic devices. In this study, the 1-pyrenemethanol (PyM) modified graphene oxide (GO) (GO-PyM) films were prepared in ethanol solution by an evaporation-induced assembly method. The PyM interacts with the GO sheets by hydrogen bonds and π-π interactions. The GO-PyM films were further graphitized at 3000 °C and roll compressed to fabricate the graphene films (GFs), by which, the PyM was transformed into nanosized graphite crystals (PNGCs). The PNGCs filled the voids between the graphene sheets of GFs and linked the graphene sheets, which enhanced the interaction between the graphene sheets, restricted the slippage of the graphene sheets under tension, increased the number of paths for electrons and phonons, and reduced the interface thermal resistance resulted from the existed voids. The resulting GFs showed excellent flexibility of a large elongation up to 14% and an elastic zone up to 3%, a tensile strength of 30.4 MPa, a thermal conductivity of 1316.32 W m-1 K-1, and an electrical conductivity of 6.48 × 105 S m-1. These integrated excellent properties of GFs will promote their applications in thermal management.

Highly Compressible and Sensitive Pressure Sensor under Large Strain Based on 3D Porous Reduced Graphene Oxide Fiber Fabrics in Wide Compression Strains.

The development of highly sensitive wearable and foldable pressure sensors is one of the central topics in artificial intelligence, human motion monitoring, and health care monitors. However, current pressure sensors with high sensitivity and good durability in low, medium, and high applied strains are rather limited. Herein, a flexible pressure sensor based on hierarchical three-dimensional and porous reduced graphene oxide (rGO) fiber fabrics as the key sensing element is presented. The internal conductive structural network is formed by the rGO fibers which are mutually contacted by interfused or noninterfused fiber-to-fiber interfaces. Thanks to the unique structures, the sensor can show an excellent sensitivity from low to high applied strains (0.24-70.0%), a high gauge factor (1668.48) at an applied compression of 66.0%, a good durability in a wide range of frequencies, a low detection limit (1.17 Pa), and anultrafast response time (30 ms). The dominated mechanism is that under compression, the slide of the graphene fibers through the polydimethylsiloxane matrix reduces the connection points between the fibers, causing a surge in electrical resistance. In addition, because graphene fibers are porous and defective, the change in geometry of the fibers also causes a change in the electrical resistance of the composite under compression. Furthermore, the interfused fiber-to-fiber interfaces can strengthen the mechanical stability under 0.01-1.0 Hz loadings and high applied strains, and the wrinkles on the surface of the rGO fibers increased the sensitivity under tiny loadings. In addition, the noninterfused fiber-to-fiber interfaces can produce a highly sensitive contact resistance, leading to a higher sensitivity at low applied strains.

Tuning the Bifunctional Oxygen Electrocatalytic Properties of Core-Shell Co3O4@NiFe LDH Catalysts for Zn-Air Batteries: Effects of Interfacial Cation Valences.

The rational design of excellent electrocatalysts is significant for triggering the slow kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable metal-air batteries. Hereby, we report a bifunctional catalytic material with core-shell structure constructed by Co3O4 nanowire arrays as cores and ultrathin NiFe-layered double hydroxides (NiFe LDHs) as shells (Co3O4@NiFe LDHs). The introduction of Co3O4 nanowires could provide abundant active sites for NiFe LDH nanosheets. Most importantly, the deposition of NiFe LDHs on the surface of Co3O4 can modulate the surface chemical valences of Co, Ni, and Fe species via changing the electron donor and/or electron absorption effects, finally achieving the balance and optimization of ORR and OER properties. By this core-shell design, the maximum ORR current densities of Co3O4@NiFe LDHs increase to 3-7 mA cm-2, almost an order of magnitude increases compared to pure NiFe LDH (0.45 mA cm-2). Significantly, an OER overpotential as low as 226 mV (35 mA cm-2) is achieved in the designed core-shell catalyst, which is comparable to and/or even better than those of commercial Ir/C. Hence, the primary zinc-air battery employing Co3O4@NiFe LDH as an air electrode achieves a high specific capacity (667.5 mA h g-1) and first-class energy density (797.6 W h kg-1); the rechargeable battery can show superior reversibility, excellent stability, and voltage gaps of ∼0.8 V (∼60% of round-trip efficiency) in >1200 continuous cycles. Furthermore, the flexible quasi-solid-state zinc-air battery with bendable ability holds practical potential in portable and wearable electronic devices.