Nontopotactic Reaction in Highly Reversible Sodium Storage of Ultrathin Co9Se8/rGO Hybrid Nanosheets

Transition metal chalcogenide with tailored nanosheet architectures with reduced graphene oxide (rGO) for high performance electrochemical sodium ion batteries (SIBs) are presented. Via one‐step oriented attachment growth, a facile synthesis of Co₉Se₈ nanosheets anchored on rGO matrix nanocomposites is demonstrated. As effective anode materials of SIBs, Co₉Se₈/rGO nanocomposites can deliver a highly reversible capacity of 406 mA h g^?1 at a current density of 50 mA g^?1 with long cycle stability. It can also deliver a high specific capacity of 295 mA h g^?1 at a high current density of 5 A g^?1 indicating its high rate capability. Furthermore, ex situ transmission electron microscopy observations provide insight into the reaction path of nontopotactic conversion in the hybrid anode, revealing the highly reversible conversion directly between the hybrid Co₉Se₈/rGO and Co nanoparticles/Na₂Se matrix during the sodiation/desodiation process. In addition, it is experimentally demonstrated that rGO plays significant roles in both controllable growth and electrochemical conversion processes, which can not only modulate the morphology of the product but also tune the sodium storage performance. The investigation on hybrid Co₉Se₈/rGO nanosheets as SIBs anode may shed light on designing new metal chalcogenide materials for high energy storage system.     

Building an interpenetrating network of Ni(OH)<Subscript>2</Subscript>/reduced graphene oxide composite by a sol–gel method

Herein, a facile sol–gel strategy for building the ordered interpenetrating network of Ni(OH)₂ and reduced graphene oxide (rGO) was proposed. In this strategy, rGO nanosheets were homogeneously fixed inside composite utilizing the pores of Ni(OH)₂ gel as template, forming rGO-interpenetrated gel network. It was found that the rGO nanosheets could effectively reduce the internal resistant of composites and provide mechanical support for the gel network of Ni(OH)₂. Therefore, the composite presented high electrochemical performance, especially high-rate performance, due to the interpenetrating of rGO nanosheets plus the supplementary role of acetylene black. It had high specific capacitance of 2163 F g^?1 at low current density of 2.9 A g^?1 and 733 F g^?1 at high current density of 86.8 A g^?1.     

Atomically Thin Mesoporous Co3O4 Layers Strongly Coupled with N‐rGO Nanosheets as High‐Performance Bifunctional Catalysts for 1D Knittable Zinc–Air Batteries

Under development for next‐generation wearable electronics are flexible, knittable, and wearable energy‐storage devices with high energy density that can be integrated into textiles. Herein, knittable fiber‐shaped zinc–air batteries with high volumetric energy density (36.1 mWh cm^?3) are fabricated via a facile and continuous method with low‐cost materials. Furthermore, a high‐yield method is developed to prepare the key component of the fiber‐shaped zinc–air battery, i.e., a bifunctional catalyst composed of atomically thin layer‐by‐layer mesoporous Co₃O₄/nitrogen‐doped reduced graphene oxide (N‐rGO) nanosheets. Benefiting from the high surface area, mesoporous structure, and strong synergetic effect between the Co₃O₄ and N‐rGO nanosheets, the bifunctional catalyst exhibits high activity and superior durability for oxygen reduction and evolution reactions. Compared to a fiber‐shaped zinc–air battery using state‐of‐the‐art Pt/C + RuO₂ catalysts, the battery based on these Co₃O₄/N‐rGO nanosheets demonstrates enhanced and stable electrochemical performance, even under severe deformation. Such batteries, for the first time, can be successfully knitted into clothes without short circuits under external forces and can power various electronic devices and even charge a cellphone.     

Preparation and Properties of Al2O3-doping LiNi1/3Co1/3Mn1/3O2 Cathode Materials

LiNi_1/3Co_1/3-xMn_1/3O₂ doped with Al₂O₃ (x = 0%, 2.5%, 5%, 10%) was synthesized by co-precipitation of Ni, Co, and Mn acetates. The influence of Al₂O₃ doping on structure and electrochemical performances of LiNi_1/3Co_1/3Mn_1/3O₂ was studied using X-ray diffraction (XRD) analysis, scanning electron microscopy, charge/discharge tester, and electrochemical workstation. It was found that the materials achieved the best electrochemical properties when x was 5%. The first discharge capacity was 156.3 mAh · g^?1(0.1 C, 2.0–4.8 V), which was close to the un-doped sample (156.8 mAh · g^?1). After 20 cycles, the capacity retention ratios at the C-ratios of 0.1C, 0.2C, and 0.5 C were 96.1%, 94.9%, and 89.4%, respectively, while the capacity retention ratios of the un-doped samples were only 92.6% (0.1 C), 91.8% (0.2 C), and 88.7% (0.5C). The alternating current impedance shows that the charge transfer in the electrode interface was the easiest when x was 5%.     

Co3O4负载rGO/g-C3N4臭氧光催化降解2,4-二氯苯氧乙酸活性研究

通过简单的水热法制备了Co₃O₄/rGO/g-C₃N₄催化剂,并在可见光照射下用于光催化臭氧氧化降解2,4-二氯苯氧乙酸(2,4-D)。利用XRD, SEM, TEM, XPS, UV-vis DRS, FT-IR和瞬态光电流对样品进行测试表征。研究表明,Co₃O₄, rGO和g-C₃N₄形成异质结后光生电子-空穴(e^--h⁺)对的分离效率,e^-的迁移能力以及光催化臭氧氧化活性都明显提升。此外,0.5Co₃O₄/0.25rGO/GCN对2,4-D具有100%的去除率,并具有最高反应速率(k=0.070 9 min^-1)。经过计算得出光催化臭氧氧化2,4-D的协同因子为3.91,表明光催化和臭氧氧化间具有较好的协同效应。活性组分的捕获实验结果表明h⁺和·OH是光催...     

Electrostatically Assembling 2D Nanosheets of MXene and MOF‐Derivatives into 3D Hollow Frameworks for Enhanced Lithium Storage

As an essential member of 2D materials, MXene (e.g., Ti₃C₂T_x) is highly preferred for energy storage owing to a high surface‐to‐volume ratio, shortened ion diffusion pathway, superior electronic conductivity, and neglectable volume change, which are beneficial for electrochemical kinetics. However, the low theoretical capacitance and restacking issues of MXene severely limit its practical application in lithium‐ion batteries (LIBs). Herein, a facile and controllable method is developed to engineer 2D nanosheets of negatively charged MXene and positively charged layered double hydroxides derived from ZIF‐67 polyhedrons into 3D hollow frameworks via electrostatic self‐assembling. After thermal annealing, transition metal oxides (TMOs)@MXene (CoO/Co₂Mo₃O₈@MXene) hollow frameworks are obtained and used as anode materials for LIBs. CoO/Co₂Mo₃O₈ nanosheets prevent MXene from aggregation and contribute remarkable lithium storage capacity, while MXene nanosheets provide a 3D conductive network and mechanical robustness to facilitate rapid charge transfer at the interface, and accommodate the volume expansion of the internal CoO/Co₂Mo₃O₈. Such hollow frameworks present a high reversible capacity of 947.4 mAh g^?1 at 0.1 A g^?1, an impressive rate behavior with 435.8 mAh g^?1 retained at 5 A g^?1, and good stability over 1200 cycles (545 mAh g^?1 at 2 A g^?1).     

Self-templated formation of tremella-like MoS<Subscript>2</Subscript> with expanded spacing of (002) crystal planes for Li-ion batteries

Tremella-like MoS₂ consisting of ultrathin nanosheets (~7 nm in thickness) is prepared via a one-pot hydrothermal reaction without using any surfactants and templates. The reaction involves transforming precursor MoO₃ to polyhedral intermediate (K₂NaMoO₃F₃ and K₃Mo₂O₄F₅) through its reaction with Na⁺, K⁺, and F^? ions in the initial stage of hydrothermal reaction. Then the polyhedral intermediate acting as the sacrifice template reacts with the S^2? released from a hydrolysis process of SCN^? ion and transforms to tremella-like MoS₂. The obtained MoS₂ product exhibits expended spacing of the (002) crystal plane, which can facilitate faster lithium ions intercalation behavior. This tremella-like MoS₂ used as an anode material for lithium-ion batteries shows a very high reversible capacity of 693 mA h g^?1 after 50 cycles, good rate capability, and high cyclic capacity retention. Even cycled at a high current density of 4800 mA g^?1, the tremella-like MoS₂ still can deliver a high capacity of 252 mA h g^?1. The secondary hierarchical microstructures consisting of ultrathin nanosheets are beneficial to greatly improved electrochemical performance of the MoS₂ electrode.     

Non-aqueous rechargeable Al–O2 battery with a bifunctional catalyst of carbon microspheres

Non-aqueous secondary Al-O₂ batteries have recently received much attention due to their high theoretical capacity, element richness, safety and low cost, although there are still many problems to be overcome. In this paper, a type of Al-O₂ battery using AlCl₃/[EMIm]Cl ionic liquid as electrolyte and carbon microspheres (CMs) as air electrode was considered. The batteries with CMs deliver a high specific capacity of 820 mAh g^?1 in the first cycle at the current density of 25 mA g^?1 and a low charge voltage. In addition, CMs show better redox catalytic activity for O₂ compared with super-p (SP) and the Al-O₂ batteries have two obvious oxygen reduction processes corresponding to two reductive peaks.     

Flexible and Binder‐Free Electrodes of Sb/rGO and Na3V2(PO4)3/rGO Nanocomposites for Sodium‐Ion Batteries

Flexible power sources have shown great promise in next‐generation bendable, implantable, and wearable electronic systems. Here, flexible and binder‐free electrodes of Na₃V₂(PO₄)₃/reduced graphene oxide (NVP/rGO) and Sb/rGO nanocomposites for sodium‐ion batteries are reported. The Sb/rGO and NVP/rGO paper electrodes with high flexibility and tailorability can be easily fabricated. Sb and NVP nanoparticles are embedded homogenously in the interconnected framework of rGO nanosheets, which provides structurally stable hosts for Na‐ion intercalation and deintercalation. The NVP/rGO paper‐like cathode delivers a reversible capacity of 113 mAh g^?1 at 100 mA g^?1 and high capacity retention of ≈96.6% after 120 cycles. The Sb/rGO paper‐like anode gives a highly reversible capacity of 612 mAh g^?1 at 100 mA g^?1, an excellent rate capacity up to 30 C, and a good cycle performance. Moreover, the sodium‐ion full cell of NVP/rGO//Sb/rGO has been fabricated, delivering a highly reversible capacity of ≈400 mAh g^?1 at a current density of 100 mA g^?1 after 100 charge/discharge cycles. This work may provide promising electrode candidates for developing next‐generation energy‐storage devices with high capacity and long cycle life.     

Core–Shell Nitrogen‐Doped Carbon Hollow Spheres/Co3O4 Nanosheets as Advanced Electrode for High‐Performance Supercapacitor

Co₃O₄/nitrogen‐doped carbon hollow spheres (Co₃O₄/NHCSs) with hierarchical structures are synthesized by virtue of a hydrothermal method and subsequent calcination treatment. NHCSs, as a hard template, can aid the generation of Co₃O₄ nanosheets on its surface; while SiO₂ spheres, as a sacrificed‐template, can be dissolved in the process. The prepared Co₃O₄/NHCS composites are investigated as the electrode active material. This composite exhibits an enhanced performance than Co₃O₄ itself. A higher specific capacitance of 581 F g^?1 at 1 A g^?1 and a higher rate performance of 91.6% retention at 20 A g^?1 are achieved, better than Co₃O₄ nanorods (318 F g^?1 at 1 A g^?1 and 67.1% retention at 20 A g^?1). In addition, the composite is employed as a positive electrode to fabricate an asymmetric supercapacitor. The device can deliver a high energy density of 34.5 Wh kg^?1 at the power density of 753 W kg^?1 and display a desirable cycling stability. All of these attractive results make the unique hierarchical Co₃O₄/NHCS core–shell structure a promising electrode material for high‐performance supercapacitors.     

Synthesis and characterization of binary transition metal oxide/reduced graphene oxide nanocomposites and its enhanced electrochemical properties for supercapacitor applications

SnO₂/Co₃O₄ (BTMO) with reduced graphene oxide (rGO) nanocomposite were synthesized by co-precipitation method to determine its electrochemical properties for the betterment of Supercapacitor applications. The XRD pattern of BTMO/rGO nanocomposite shows tetragonal rutile and spinal cubic structure. The XRD peak of BTMO/rGO nanocomposite is comparatively broader than the BTMO nanocomposite and bare nanoparticles due to the presence of high surface area rGO. From the SEM image it is observed that the BTMO nanocomposite has comparatively larger particles than the bare nanoparticles and BTMO/rGO nanocomposites. Hence, the BTMO/rGO nanocomposite has alteration in surface to volume ratio and improved electron conductivity were observed with increased integral area and current such as 2.5117?×?10^?4 A/s and 3.1686?×?10^?4 A respectively in CV behavior, when it is compared to BTMO nanocomposite and bare nanoparticles. The BTMO/rGO nanocomposite also has an increased specific capacitance value of 317.2 F/g at 1 A/g. The increased specific capacitance value of BTMO/rGO nanocomposites are mainly due to the synergistic effect between SnO₂/Co₃O₄ and rGO. Hence, it may be responsible for the improved electron conductivity, due to the free diffusion pathway for the fast ion movement and also it has easily ion accessibility nature to the storage sites makes the materials with both the electric double layer capacitance and pseudocapacitance behavior. Hence, BTMO/rGO nanocomposite would be a promising candidate material for energy storage supercapacitor application.     

3D composites of ZnSnO<Subscript>3</Subscript> nanoplates/reduced graphene oxide aerogels as an advanced lithium-ion battery anode

Zinc-based bimetal oxides have received considerable attention as anode for lithium-ion batteries (LIBs). A one-pot self-assembly hydrothermal method is developed for the fabrication of 3D hierarchical structure aerogels from zinc stannate (ZnSnO₃) and reduced graphene oxide (rGO). 3D interconnected porous structure with ZnSnO₃ hexagon nanoplates uniformly dispersed on graphene sheets has been constructed successfully, in which the crystalline hexagon nanoplates ZnSnO₃ are firstly used to prepare ZnSnO₃-based anode materials for LIBs. The as-prepared ZnSnO₃ nanoplates/reduced graphene oxide aerogels (ZnSnO₃–rGAs) electrode demonstrates an excellent reversible capacity (780 mAh g^?1) after 200 cycles at a certain current density (100 mA g^?1) and still delivers a specific capacity of 460 mAh g^?1 even at 1000 mA g^?1. The superior performance of lithium storage is attributed to the 3D porous hierarchical structure and the synergistic effects of uniform hexagon nanoplates ZnSnO₃ and rGO sheets.     

Ionic liquid-derived Co<Subscript>3</Subscript>O<Subscript>4</Subscript>/carbon nano-onions composite and its enhanced performance as anode for lithium-ion batteries

In this work, a novel composite of Co₃O₄ nanoparticle and carbon nano-onions (CNOs) is synthesized by using ionic liquid as carbon and nitrogen source through a facile carbothermic reduction followed by low-temperature oxidation method. The SEM and HRTEM images reveal that the Co₃O₄ particles are homogenously embedded in the CNOs. Due to the unique nano-structure, the electrolyte contacts well with the active materials, leading to a better transfer of lithium ions. Moreover, the unique nano-structure not only buffers the volume changes but also facilitates the shuttling of electrons during the cycling process. As a result, the electrode made up of Co₃O₄/CNOs composite delivers favorable cycling performance (676 mAh g^?1 after 200 cycles) and rate capability (557 mAh g^?1 at the current of 1 C), showing a promising prospect for lithium-ion batteries as anode materials.     

One-step preparation of graphene nanosheets via ball milling of graphite and the application in lithium-ion batteries

An improved method for mass production of good-quality graphene nanosheets (GNs) via ball milling pristine graphite with dry ice is presented. We also report the enhanced performance of these GNs as working electrode in lithium-ion batteries (LIBs). In this improved method, the decrease of necessary ball milling time from 48 to 24 h and the increase of Brunauer–Emmett–Teller surface area from 389.4 to 490 m²/g might be resulted from the proper mixing of stainless steel balls with different diameters and the optimization of agitation speed. The as-prepared GNs are investigated in detail using a number of techniques, such as scanning electron microscope, atomic force microscope, high-resolution transmission electron microscopy, selected area electron diffraction, X-ray diffractometer, and Fourier transform infrared spectroscopic. To demonstrate the potential applications of these GNs, the performances of the LIBs with pure Fe₃O₄ electrode and Fe₃O₄/graphene (Fe₃O₄/G) composite electrode were carefully evaluated. Compared to Fe₃O₄-LIBs, Fe₃O₄/G-LIBs exhibited prominently enhanced performance and a reversible specific capacity of 900 mAh g^?1 after 5 cycles at 100 and 490 mAh g^?1 after 5 cycles at 800 mA g^?1. The improved cyclic stability and enhanced rate capability were also obtained.     

Construction of Complex Co3O4@Co3V2O8 Hollow Structures from Metal–Organic Frameworks with Enhanced Lithium Storage Properties

A novel metal–organic‐framework‐engaged strategy is demonstrated for the preparation of multishelled Co₃O₄@Co₃V₂O₈ hybrid nanoboxes. This strategy relies on the unique reaction of zeolitic imidazolate framework‐67 with the vanadium source of vanadium oxytriisopropoxide. Benefitting from the synthetic versatility, a series of nanostructures can be realized including triple‐shelled and double‐shelled Co₃O₄@Co₃V₂O₈ nanoboxes and single‐shelled Co₃V₂O₈ nanoboxes. When evaluated as electrode materials for lithium‐ion batteries, these unique hollow structures demonstrate remarkable lithium storage properties. For example, the triple‐shelled Co₃O₄@Co₃V₂O₈ nanoboxes retain a high capacity of 948 mAh g^?1 after 100 cycles at 100 mA g^?1.     

Ultrafine Co3O4 Nanoparticles within Nitrogen‐Doped Carbon Matrix Derived from Metal–Organic Complex for Boosting Lithium Storage and Oxygen Evolution Reaction

Transition metal oxides have recently received great attention for application in advanced lithium‐ion batteries (LIBs) and oxygen evolution reaction (OER). Herein, the ethylenediaminetetraacetic cobalt complex as a precursor to synthesize ultrafine Co₃O₄ nanoparticles encapsulated into a nitrogen‐doped carbon matrix (NC) composites is presented. The as‐prepared Co₃O₄/NC‐350 obtained by pyrolysis at 350 °C demonstrates superior rate performance (372 mAh g^?1 at 5.0 A g^?1) and high cycling stability (92% capacity retention after 300 cycles at 1.0 A g^?1) as anode for LIBs. When evaluated as an electrocatalyst for OER, the Co₃O₄/NC‐350 achieves an overpotential of 298 mV at a current density of 10 mA cm^?2. The NC‐encapsualted porous hierarchical structure assures fast and continuous electron transportation, high activity sites, and strong structural integrity. This works offers novel complex precursors for synthesizing transition metal–based electrodes for boosting electrochemical energy conversion and storage.     

Synthesis of Li<Subscript>1.2</Subscript>Mn<Subscript>0.54</Subscript>Co<Subscript>0.13</Subscript>Ni<Subscript>0.13</Subscript>O<Subscript>2</Subscript> by sol–gel method and its electrochemical properties as cathode materials for lithium-ion batteries

Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ was synthesized by sol–gel method at 700, 800, 900 and 1000 °C, respectively, characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and measured as the cathode materials for lithium-ion batteries (LIBs). After their performances have been compared, 800 °C was considered as the optimum synthesis temperature for Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ as the cathode materials for LIBs. When charge–discharged at 20 mA g^?1 in a voltage window of 2.0–4.8 V, the Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ synthesized at 800 °C (LMNCO-800) showed charge and discharge capacities of 376.2 and 276.3 mAh g^?1, respectively, with irreversible capacity of 99.9 mAh g^?1 and Coulombic efficiency of 73.4%, in the first charge–discharge cycle. The discharge capacity was 239.0 mAh g^?1 in the 50th charge–discharge cycle, with capacity retention of 86.6%. The LMNCO-800 also showed superior high-rate performances. When cycled at the rates of 0.5, 1, 2 and 5 C rate (1 C?=?200 mA g^?1), the discharge capacities of the Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ can reach 241, 171, 150 and 110 mAh g^?1, respectively. When characterized with high-resolution transmission electron microscopy (TEM), nanodomains with two different structures can be found in LMNCO-800, with some nanodomains showing monoclinic Li₂MnO₃ structure and the other nanodomains showing hexagonal LiMO₂ structure.     

Efficient Laser‐Induced Construction of Oxygen‐Vacancy Abundant Nano‐ZnCo2O4/Porous Reduced Graphene Oxide Hybrids toward Exceptional Capacitive Lithium Storage

Recently, binary ZnCo₂O₄ has drawn enormous attention for lithium‐ion batteries (LIBs) as attractive anode owing to its large theoretical capacity and good environmental benignity. However, the modest electrical conductivity and serious volumetric effect/particle agglomeration over cycling hinder its extensive applications. To address the concerns, herein, a rapid laser‐irradiation methodology is firstly devised toward efficient synthesis of oxygen‐vacancy abundant nano‐ZnCo₂O₄/porous reduced graphene oxide (rGO) hybrids as anodes for LIBs. The synergistic contributions from nano‐dimensional ZnCo₂O₄ with rich oxygen vacancies and flexible rGO guarantee abundant active sites, fast electron/ion transport, and robust structural stability, and inhibit the agglomeration of nanoscale ZnCo₂O₄, favoring for superb electrochemical lithium‐storage performance. More encouragingly, the optimal L‐ZCO@rGO‐30 anode exhibits a large reversible capacity of ≈1053 mAh g^?1 at 0.05 A g^?1, excellent cycling stability (≈746 mAh g^?1 at 1.0 A g^?1 after 250 cycles), and preeminent rate capability (≈686 mAh g^?1 at 3.2 A g^?1). Further kinetic analysis corroborates that the capacitive‐controlled process dominates the involved electrochemical reactions of hybrid anodes. More significantly, this rational design holds the promise of being extended for smart fabrication of other oxygen‐vacancy abundant metal oxide/porous rGO hybrids toward advanced LIBs and beyond.     

Single-Step Synthesis of Sr4V2O6Fe2As2: The Blocking Layer Based Potential Future Superconductor

We report synthesis, structural details and transport measurements on Sr₄V₂O₆Fe₂As₂. Namely, the stoichiometric amounts of V₂O₅+1/2×SrO₂+7/2×Sr+2×FeAs are weighed mixed, ground thoroughly and palletized in rectangular form in a glove box in high purity Ar atmosphere. The pellet is further sealed in an evacuated (10^?5 torr) quartz tube and put for heat treatments at 750 and 1150°C in a single step for 12 and 36 hours respectively. Finally the quartz ampoule is allowed to cool naturally to room temperature. The as-synthesized sample is black in color. The compound crystallized in P4/nmm space group with lattice parameters a=b=3.925 Å and c=15.870 Å. Also seen are some small impurity lines. The compound did not exhibit superconductivity but instead a spin density wave (SDW) like metallic step at around 175 K is seen in R(T) measurements. Principally in [FeAs]^?1{Sr₄V₂O₆}^C[FeAs]^?1 the net value of blocking layer charge C must be either less or more than 2, to let it be electron or hole type superconductor respectively. Efforts are under way to achieve superconductivity in the studied system.     

Single-Atom Pd-N4 Catalysis for Stable Low-Overpotential Lithium-Oxygen Battery

The critical challenge for Li-O₂ batteries lies in the large charge overpotential, leading to undesirable side reactions and inferior cycle stability. Single-atom catalysts have shown promising prospects in expediting the kinetics of oxygen evolution reaction (OER) for Li-O₂ batteries. However, a present practical drawback is the limited understanding of the correlation between the unique atomic structures and the OER mechanism. Herein, a template-assisted strategy is reported to synthesize atomically dispersed Pd anchored on N-doped carbon spheres as cathode catalysts. Benefiting from the well-defined Pd-N₄ moiety, the morphology and distribution of Li₂O₂ products are distinctly regulated with optimized decomposition reversibility. Theoretical simulations reveal that the unique configuration of Pd-N₄ will contribute to the electron transfer from Pd atoms to the adjacent N atoms, which turns the originally electroneutral Pd into positively charged and downshifts the d-band center and therefore weakens its adsorption energy with the intermediates. The Li-O₂ batteries with Pd SAs/NC cathode achieve a charge overpotential of only 0.24 V and sustainable low-overpotential cycling stability (500 mA g⁻¹), and can retain a low charge voltage to a very high capacity of 10 000 mAh g⁻¹. This work provides some insights into designing efficient single-atom catalysts for stable low-overpotential Li-O₂ batteries.