Evaluation of Cathode Electrodes in Lithium-Ion Battery: Pitfalls and the Befitting Counter Electrode

Boosting energy density and reducing the cost of lithium-ion batteries are critical to accelerating their applications in transportation and grid energy storage. Battery design with increasing electrode thickness is an effective way to combine higher energy density and lower cost. However, the evaluation of electrodes with increased thickness is challenging and requires more attention. Here, some pitfalls are to be avoided and a reasonable evaluation strategy is provided for cathode electrodes regarding the choice of counter electrode. Though as the most common counter electrode, lithium metal anode is actually not suitable for evaluating cycling performance, which exhibits fast cell capacity decline, especially, in the case of areal capacity higher than 2 mAh cm⁻². Two commercial anode materials, graphite and Li₄Ti₅O₁₂ (LTO) as the potential alternatives, are systematically evaluated and compared, demonstrating LTO as the more suitable choice. The thick cathode electrode coupled with LTO exhibits excellent rate capability, stable cycling performance, and easy interpretation of charge/discharge profile. The relationship between cell balance and battery performance is further analyzed in detail. This strategy enables a reasonable evaluation of the cathode electrodes and advances the designing of thick electrode.     

Sandwich Structured Metal oxide/Reduced Graphene Oxide/Metal Oxide-Based Polymer Electrolyte Enables Continuous Inorganic–Organic Interphase for Fast Lithium-Ion Transportation

Introducing inorganic fillers into organic poly(ethylene oxide)(PEO)-based electrolyte has attracted substantial attention to enhance its ionic conductivity and mechanical strength, but limited inorganic–organic interphases are always caused by isolated particles agglomeration. Herein, a variety of sandwich structured metal oxide/reduced graphene oxide(rGO)/metal oxide nanocomposites to optimize lithium-ion conduction by interconnected amorphous organic–inorganic interphases in lithium metal batteries, are proposed. With the support of high surface area rGO, the agglomeration of metal oxide particles is precluded, forming continuous amorphous organic–inorganic interphases with stacked layer-by-layer structure, thus creating 3D interconnected lithium-ion transportation channels vertically and laterally. Besides, metal oxide nanoparticles with hydroxyls possess high affinity toward bis(tri-fluoromethanesulfonyl)imide anions by hydrogen bindings between hydroxyls and fluorine and metal-oxygen bonds, releasing more free lithium ions. Consequently, PEO-ZnO/rGO/ZnO electrolyte delivers superior ionic conductivity of 1.02 × 10⁻⁴ S cm⁻¹ at 25 °C and lithium-ion transference number of 0.38 at 60 °C. Furthermore, ZnO/rGO/ZnO insertion promotes the formation of LiF-rich stable solid electrolyte interface, endowing Li symmetric cells with long-term cycling stability over 900 hours. The corresponding LiFePO₄ cathode possesses a high reversible specific capacity of 130 mAh g⁻¹ at 0.5C after cycling 300 cycles with a poor capacity fading of 0.05% per cycle.     

Implanting CuS Quantum Dots into Carbon Nanorods for Efficient Magnesium-Ion Batteries

Magnesium-ion batteries (MIBs) are emerging as potential next-generation energy storage systems due to high security and high theoretical energy density. Nevertheless, the development of MIBs is limited by the lack of cathode materials with high specific capacity and cyclic stability. Currently, transition metal sulfides are considered as a promising class of cathode materials for advanced MIBs. Herein, a template-based strategy is proposed to successfully fabricate metal-organic framework-derived in-situ porous carbon nanorod-encapsulated CuS quantum dots (CuS-QD@C nanorods) via a two-step method of sulfurization and cation exchange. CuS quantum dots have abundant electrochemically active sites, which facilitate the contact between the electrode and the electrolyte. In addition, the tight combination of CuS quantum dots and porous carbon nanorods increases the electronic conductivity while accelerating the transport speed of ions and electrons. With these architectural and compositional advantages, when used as a cathode material for MIBs, the CuS-QD@C nanorods exhibit remarkable performance in magnesium storage, including a high reversible capacity of 323.7 mAh g⁻¹ at 100 mA g⁻¹ after 100 cycles, excellent long-term cycling stability (98.5 mAh g⁻¹ after 1000 cycles at 1.0 A g⁻¹), and satisfying rate performance (111.8 mA g⁻¹ at 1.0 A g⁻¹).     

High-Energy Interlayer-Expanded Copper Sulfide Cathode Material in Non-Corrosive Electrolyte for Rechargeable Magnesium Batteries

Rechargeable magnesium batteries (RMB) have been regarded as an alternative to lithium-based batteries because of their abundant elemental resource, high theoretical volumetric capacity, and multi-electron redox reaction without the dendrite formation of magnesium metal anode. However, their development is impeded by their poor electrode/electrolyte compatibility and the strong Coulombic effect of the multivalent Mg²⁺ ions in cathode materials. Herein, copper sulfide material is developed as a high-energy cathode for RMBs with a non-corrosive Mg-ion electrolyte. Given the benefit of its optimized interlayer structure, good compatibility with the electrolyte, and enhanced surface area, the as-prepared copper sulfide cathode exhibits unprecedented electrochemical Mg-ion storage properties, with the highest specific capacity of 477 mAh g⁻¹ and gravimetric energy density of 415 Wh kg⁻¹ at 50 mA g⁻¹, among the reported cathode materials of metal oxides, metal chalcogenides, and polyanion-type compounds for RMBs. Notably, an impressive long-term cycling performance with a stable capacity of 111 mAh g⁻¹ at 1 C (560 mA g⁻¹) is achieved over 1000 cycles. The results of the present study offer an avenue for designing high-performance cathode materials for RMBs and other multivalent batteries.     

ZIF-67/rGO/NiPc composite electrode material for high-performance asymmetric supercapacitors

In this reported study, novel multiple dimensional ZIF-67/rGO/NiPc composite materials were prepared for supercapacitors. The electrochemical test showed that the ZIF-67/rGO/NiPc electrode achieved a remarkable specific capacitance of 860 F g^?1 at a current density of 1 A g^?1, which was superior to that of the rGO/NiPc and ZIF-67/rGO electrodes. An asymmetric supercapacitor based on ZIF-67/rGO/NiPc//activated carbon exhibited a high specific capacitance of 200.67 F g^?1 and an extraordinary energy density of 62.7 Wh kg^?1 at a corresponding power density of 750 W kg^?1. In addition, the device demonstrated 94.6% capacitance retention after 5000 cycles. The assembled asymmetric supercapacitors could easily powered a green light-emitting diode. This work revealed a promising research route for the rational construction of multiple dimensioned high-performance electrodes materials for use in new energy storage devices.

     

NiCo2S4 nanoparticles grown on reduced graphene oxides for high-performance asymmetric supercapacitors

The nanostructures of reduced graphene oxide (rGO)/NiCo₂S₄ are prepared using the simple hydrothermal method and the thermal treatment process, which could provide good conductivity and ideal specific surface area. The rGO/NiCo₂S₄ electrode shows a maximum specific capacitance of 1059 F g⁻¹, excellent rate capability, and good cycle life. Furthermore, the three dimensional structures of rGO/MnO (3D rGO/MnO) are also synthesized by the hydrothermal method and the thermal treatment process, which have the high specific surface area and good conductivity. The rGO/MnO electrode exhibits a maximum specific capacitance of 469 F g⁻¹. A rGO/MnO//rGO/NiCo₂S₄ asymmetric supercapacitors (ASC) is assembled using 2 M KOH solution as electrolyte, rGO/NiCo₂S₄ as positive electrode and rGO/MnO as negative electrode. The rGO/MnO//rGO/NiCo₂S₄ ASC shows an energy density of 38.8 Wh kg⁻¹ at a power density of 0.4 kW kg⁻¹ and a good cycle life, which provides a possibility toward actual application in energy-storage systems.     

Structural Transformation by Crystal Engineering Endows Aqueous Zinc-Ion Batteries with Ultra-long Cyclability

Manganese oxide is a promising cathode material for aqueous zinc batteries. However, its weak structural stability, low electrical conductivity, and sluggish reaction kinetics lead to rapid capacity fading. Herein, a crystal engineering strategy is proposed to construct a novel MnO₂ cathode material. Both experimental results and theoretical calculations demonstrate that Al-doping plays a crucial role in phase transition and doping-superlattice structure construction, which stabilizes the structure of MnO₂ cathode materials, improves conductivity, and accelerates ion diffusion dynamics. As a result, 1.98% Al-doping MnO₂ (AlMO) cathode shows an incredible 15 000 cycle stability with a low capacity decay rate of 0.0014% per cycle at 4 A g⁻¹. Additionally, it provides superior specific capacity of 311.2 mAh g⁻¹ at 0.1 A g⁻¹ and excellent rate performance (145.2 mAh g⁻¹ at 5.0 A g⁻¹). To illustrate the potential of 1.98%AlMO to be applied in actual practice, flexible energy storage devices are fabricated and measured. These discoveries provide a new insight for structural transformation via crystal engineering, as well as a new avenue for the rational design of electrode material in other battery systems.     

Toward Rapid-Charging Sodium-Ion Batteries using Hybrid-Phase Molybdenum Sulfide Selenide-Based Anodes

To attain both high energy density and power density in sodium-ion (Na⁺) batteries, the reaction kinetics and structural stability of anodes should be improved by materials optimization. In this work, few-layered molybdenum sulfide selenide (MoSSe) consisting of a mixture of 1T and 2H phases is designed to provide high ionic/electrical conductivities, low Na⁺ diffusion barrier, and stable Na⁺ storage. Reduced graphene oxide (rGO) is used as a conductive matrix to form 3D electron transfer paths. The resulting MoSSe@rGO anode exhibits high capacity and rate performance in both organic and solid-state electrolytes. The ultrafast Na⁺ storage kinetics of the MoSSe@rGO anode is attributed to the surface-dominant reaction process and broad Na⁺ channels. In situ and ex situ measurements are conducted to reveal the Na⁺ storage process in MoSSe@rGO. It is found that the Mo S and Mo Se bonds effectively limit the dissolution of the active materials. The favorable Na⁺ storage kinetics of the MoSSe@rGO electrode are ascribed to its low adsorption energy of −1.997 eV and low diffusion barrier of 0.087 eV. These results reveal that anion doping of metal sulfides is a feasible strategy to develop sodium-ion batteries with high energy and power densities and long life-span.     

Nanoscale Borate Coating Network Stabilized Iron Oxide Anode for High-Energy-Density Bipolar Lithium-Ion Batteries

High-capacity metal oxides based on non-toxic earth-abundant elements offer unique opportunities as advanced anodes for lithium-ion batteries (LIBs). But they often suffer from large volumetric expansion, particle pulverization, extensive side reactions, and fast degradations during cycling. Here, an easy synthesis method is reported to construct amorphous borate coating network, which stabilizes conversion-type iron oxide anode for the high-energy-density semi-solid-state bipolar LIBs. The nano-borate coated iron oxide anode has high tap density (1.6 g cm⁻³), high capacity (710 mAh g⁻¹ between 0.5 – 3.0 V, vs Li/Li⁺), good rate performance (200 mAh g⁻¹ at 50 C), and excellent cycling stability (≈100% capacity resention over 1,000 cycles at 5 A g⁻¹). When paired with high-voltage cathode LiCoO₂, it enables Cu current collector-free pouch-type classic and bipolar full cells with high voltage (7.6 V with two stack layers), achieving high energy density (≈350 Wh kg⁻¹), outstanding power density (≈6,700 W kg⁻¹), and extended cycle life (75% capacity retention after 2,000 cycles at 2 C), superior to the state-of-the-art high-power LIBs using Li₄Ti₅O₁₂ anode. The design and methodology of the nanoscale polyanion-like coating can be applied to other metal oxides electrode materials, as well as other electrochemical materials and devices.     

Metal Coordinated Polymer as Three-Dimensional Network Binder for High Sulfur Loading Cathode of Lithium–Sulfur Battery

The construction of high sulfur (S) loading cathode is one of the critical parameters to obtain lithium–sulfur (Li–S) batteries with high energy density, but the slow redox reaction rate of high S loading cathode limits the development process. In this paper, a metal coordinated polymer-based three-dimensional network binder, which can improve the reaction rate and stability of S electrode. Compared with traditional linear polymer binders, the metal coordinated polymer binder can not only increase the load amount of S through the three-dimensional cross-linking, but also promote the interconversion reactions between S and lithium sulfide (Li₂S), avoiding the passivation of electrode and improving the stability of the positive electrode. At an S load of 4–5 mg cm⁻² and an E/S ratio of 5.5 µL mg⁻¹, the discharged voltage in the second platform is 2.04 V and the initial capacity is 938 mA h g⁻¹ with metal coordinated polymer binder. Moreover, the capacity retention rate approaches 87% after 100 cycles. In comparison, the discharged voltage in the second platform is lost and the initial capacity is 347 mA h g⁻¹ with PVDF binder. It demonstrates the advanced properties of metal-coordinated polymer binders for improving the performance of Li–S batteries.     

A Molecularly Engineered Cathode Lithium Compensation Agent for High Energy Density Batteries

Prelithiating cathode is considered as one of the most promising lithium compensation strategies for practical high energy density batteries. Whereas most of reported cathode lithium compensation agents are deficient owing to their poor air-stability, residual insulating solid, or formidable Li-extracting barrier. Here, this work proposes molecularly engineered 4-Fluoro-1,2-dihydroxybenzene Li salt (LiDF) with high specific capacity (382.7 mAh g⁻¹) and appropriate delithiation potential (3.6–4.2 V) as an air-stable cathode Li compensation agent. More importantly, the charged residue 4-Fluoro-1,2-benzoquinone (BQF) can synergistically work as an electrode/electrolyte interface forming additive to build uniform and robust LiF-riched cathode/anode electrolyte interfaces (CEI/SEI). Consequently, less Li loss and retrained electrolyte decomposition are achieved. With 2 wt% 4-Fluoro-1,2-dihydroxybenzene Li salt initially blended within the cathode, 1.3 Ah pouch cells with NCM (Ni92) cathode and SiO/C (550 mAh g⁻¹) anode can keep 91% capacity retention after 350 cycles at 1 C rate. Moreover, the anode free of NCM622+LiDF||Cu cell achieves 78% capacity retention after 100 cycles with the addition of 15 wt% LiDF. This work provides a feasible sight for the rational designing Li compensation agent at molecular level to realize high energy density batteries.     

Nanocarved vanadium nitride nanowires encapsulated in lamellar graphene layers as supercapacitor electrodes

Supercapacitors have the characteristics of high specific capacitance, long cycle life and fast charging ability, which have shown extremely valuable applications in energy storage fields. Improving the electrode materials is a crucial approach to achieve high capacity. Vanadium nitride (VN) has higher theoretical capacitance than noble metal oxides, as well as better chemical stability and good electrical conductivity. Herein, a composite of VN nanowires with multiple cavities encapsulated in N-doped reduced graphene oxide lamellar layers (VNNWs@rGO) has been synthesized by facile freeze-casting and subsequent nitridation technique. The hierarchical VNNWs@rGO composite exhibited excellent supercapacitor performance: high capacitances of 222 and 65 F g^?1 were achieved at current densities of 0.5 and 10 A g^?1, respectively. The improved electrochemical performance is associated with the unique structural design: the N-doped rGO sheets endowed enhanced electric conductivity and chemical stability for VN, the interconnected laminar network of VNNWs@rGO are crucial for electrolyte penetration and charge transfer, and the cavities and nanoparticles inside the VN nanowires can provide abundant active sites for electric double-layer capacitor and pseudocapacitance.

     

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.     

Redox Electrolytes-Assisting Aqueous Zn-Based Batteries by Pseudocapacitive Multiple Perovskite Fluorides Cathode and Charge Storage Mechanisms

Aqueous Zn-based batteries (AZBs) have attracted intensive attention. However, to explore advanced cathode materials with in-depth elucidation of their charge storage mechanisms, improve energy storage capacity, and construct novel cell systems remain a great challenge. Herein, a new pseudocapacitive multiple perovskite fluorides (ABF₃) cathode is designed, represented by KMF-(IV, V, and VI; M = NiCoMnZn/-Mg/-MgFe), and constructed Zn//KMF-(IV, V, and VI) AZBs and their flexible devices. Ex situ tests have revealed a typical bulk phase conversion mechanism of KMF-VI electrode for charge storage in alkaline media dominated by redox-active Ni/Co/Mn species, with transformation of ABF₃ nanocrystals into amorphous metal oxide/(oxy)hydroxide nanosheets. By employing single or bipolar redox electrolyte strategies of 20 mm [Fe(CN)₆]³⁻ or/and 10 mm SO₃²⁻/Cu[(NH₃)₄]²⁺ acting on KMF-(IV, V, and VI) cathode and Zn anode, the AZBs show an improved energy storage owing to additional capacity contribution of redox electrolytes. The as-designed Zn//polyvinyl alcohol (PVA)-KOH-K₃[Fe(CN)₆]//KMF-(IV, V, and VI) redox gel electrolytes-assisting flexible AZBs (RGE-FAZBs) exhibit remarkable performance under different bending angles because of slight dissolution corrosion of zinc anode compared with liquid electrolytes. Overall, the work demonstrates the novel idea of conversion-type multiple ABF₃ cathode for redox electrolytes-assisting AZBs (RE-AZBs) and their flexible systems, showing great significance on electrochemical energy storage.     

Multifunctional Nanocrystalline-Assembled Porous Hierarchical Material and Device for Integrating Microwave Absorption,Electromagnetic Interference Shielding,and Energy Storage

Multifunctional applications including efficient microwave absorption and electromagnetic interference (EMI) shielding as well as excellent Li-ion storage are rarely achieved in a single material. Herein, a multifunctional nanocrystalline-assembled porous hierarchical NiO@NiFe₂O₄/reduced graphene oxide (rGO) heterostructure integrating microwave absorption, EMI shielding, and Li-ion storage functions is fabricated and tailored to develop high-performance energy conversion and storage devices. Owing to its structural and compositional advantages, the optimized NiO@NiFe₂O₄/15rGO achieves a minimum reflection loss of −55 dB with a matching thickness of 2.3 mm, and the effective absorption bandwidth is up to 6.4 GHz. The EMI shielding effectiveness reaches 8.69 dB. NiO@NiFe₂O₄/15rGO exhibits a high initial discharge specific capacity of 1813.92 mAh g⁻¹, which reaches 1218.6 mAh g⁻¹ after 289 cycles and remains at 784.32 mAh g⁻¹ after 500 cycles at 0.1 A g⁻¹. In addition, NiO@NiFe₂O₄/15rGO demonstrates a long cycling stability at high current densities. This study provides an insight into the design of advanced multifunctional materials and devices and provides an innovative method of solving current environmental and energy problems.     

Rational Design of a High-Loading Polysulfide Cathode and a Thin-Lithium Anode for Developing Lean-Electrolyte Lithium–Sulfur Full Cells

Lithium-sulfur cells are attractive energy-storage systems because of their high energy density and the electrochemical utilization rates of the high-capacity lithium-metal anode and the low-cost sulfur cathode. The commercialization of high-performance lithium–sulfur cells with high discharge capacity and cyclic stability requires the optimization of practical cell-design parameters. Herein, a carbon structural material composed of a carbon nanotube skeleton entrapping conductive graphene is synthesized as an electrode substrate. The carbon structural material is optimized to develop a high-loading polysulfide cathode with a high sulfur loading capacity (6–12 mg cm⁻²), rate performance (C/10–C/2), and cyclic stability for 200 cycles. A thin lithium anode based on the carbon structural material is developed and exhibits long lithium stripping/plating stability for ≈2500 h with a lithium-ion transference number of 0.68. A lean-electrolyte lithium–sulfur full cell with a low electrolyte-to-sulfur ratio of 6 µL mg⁻¹ is constructed with the designed high-loading polysulfide cathode and the thin lithium anode. The integration of all the critical cell-design parameters endows the lithium–sulfur full cell with a low negative-to-positive capacity ratio of 2.4, while exhibiting stable cyclability with an initial discharge capacity of 550 mAh g⁻¹ and 60% capacity retention after 200 cycles.     

Multicomponent Hybridization Transition Metal Oxide Electrode Enriched with Oxygen Vacancy for Ultralong-Life Supercapacitor

Transition metal oxide electrode materials for supercapacitors suffer from poor electrical conductivity and stability, which are the research focus of the energy storage field. Herein, multicomponent hybridization Ni-Cu oxide (NCO-Ar/H₂-10) electrode enriched with oxygen vacancy and high electrical conductivity including the Cu_0.2Ni_0.8O, Cu₂O and CuO is prepared by introducing Cu element into Ni metal oxide with hydrothermal, annealing, and plasma treatment. The NCO-Ar/H₂-10 electrode exhibits high specific capacity (1524 F g⁻¹ at 3 A g⁻¹), good rate performance (72%) and outstanding cyclic stability (109% after 40,000 cycles). The NCO-Ar/H₂-10//AC asymmetric supercapacitor (ASC) achieves high energy density of 48.6 Wh kg⁻¹ at 799.6 W kg⁻¹ while exhibiting good cycle life (117.5% after 10,000 cycles). The excellent electrochemical performance mainly comes from the round-trip valence change of Cu⁺/Cu²⁺ in the multicomponent hybridization enhance the surface capacitance during the redox process, and the change of electronic microstructure triggered by a large number of oxygen vacancies reduce the adsorption energy of OH⁻ ions of thin nanosheet with crack of surface edge, ensuring electron and ion-transport processes and remitting the structural collapse of material. This work provides a new strategy for improving the cycling stability of transition metal oxide electrode materials.     

The Structural and Electronic Engineering of Molybdenum Disulfide Nanosheets as Carbon-Free Sulfur Hosts for Boosting Energy Density and Cycling Life of Lithium–Sulfur Batteries

The compact sulfur cathodes with high sulfur content and high sulfur loading are crucial to promise high energy density of lithium–sulfur (Li–S) batteries. However, some daunting problems, such as low sulfur utilization efficiency, serious polysulfides shuttling, and poor rate performance, are usually accompanied during practical deployment. The sulfur hosts play key roles. Herein, the carbon-free sulfur host composed of vanadium-doped molybdenum disulfide (VMS) nanosheets is reported. Benefiting from the basal plane activation of molybdenum disulfide and structural advantage of VMS, high stacking density of sulfur cathode is allowed for high areal and volumetric capacities of the electrodes together with the effective suppression of polysulfides shuttling and the expedited redox kinetics of sulfur species during cycling. The resultant electrode with high sulfur content of 89 wt.% and high sulfur loading of 7.2 mg cm⁻² achieves high gravimetric capacity of 900.9 mAh g⁻¹, the areal capacity of 6.48 mAh cm⁻², and volumetric capacity of 940 mAh cm⁻³ at 0.5 C. The electrochemical performance can rival with the state-of-the-art those in the reported Li–S batteries. This work provides methodology guidance for the development of the cathode materials to achieve high-energy-density and long-life Li–S batteries.     

High Areal Capacity,Long Cycle Life Li–Air Batteries Enabled by Nano/Micro Hierarchical Porous Cathode

The limited cycle life of Li–air batteries (LABs) with high areal capacity remains the chief challenge that hinders their practical applications. Here, the study proposes a hierarchical porous electrode (HPE) design strategy, in which porous MnO nanoflowers are built into mesopore/macropore electrodes through a combination of chemical dealloying and physical de-templating procedures. The MnO nanoflowers with 10–30 nm pore provides active sites to catalyze the O₂ reduction and decomposition of discharged products. The 5–10 µm macroscopic pores in the cathode serve as channels of O₂ transportation and facilitate the electrolyte permeation. The proposed HPE exhibits a full discharge capacity of 17.49 mAh cm⁻² and stable cycle life >2000 h with a limited capacity of 6 mAh cm⁻². These results suggest that the HPE design strategy for LABs can simultaneously provide large capacity and robust cycle life, which is promising for advanced metal–air batteries.     

Designing Advanced In Situ Electrode/Electrolyte Interphases for Wide Temperature Operation of 4.5 V Li||LiCoO2 Batteries

High-energy-density batteries with a LiCoO₂ (LCO) cathode are of significant importance to the energy-storage market, especially for portable electronics. However, their development is greatly limited by the inferior performance under high voltages and challenging temperatures. Here, highly stable lithium (Li) metal batteries with LCO cathode, through the design of in situ formed, stable electrode/electrolyte interphases on both the Li anode and the LCO cathode, with an advanced electrolyte, are reported. The LCO cathode can deliver a high specific capacity of ≈190 mAh g⁻¹ and show greatly improved cell performances under a high charge voltage of 4.5 V (even up to 4.55 V) and a wide temperature range from −30 to 55 °C. This work points out a promising approach for developing Li||LCO batteries for practical applications. This approach can also be used to improve the high-voltage performance of other batteries in a broad temperature range.