Tungsten chalcogenides as anodes for potassium-ion batteries

Potassium-ion batteries(PIBs)by virtue of their strong cost competitiveness and similar electrochemical properties to lithiumion batteries have been deemed to be a promising electrochemical energy storage technology.To promote the application in the commercial market,developing electrode materials with high specifi c capacities,superior cycling stability,and reliable safety is of great importance.Anode materials as an important component of PIBs play a decisive role,among which twodimensional transition metal chalcogenides(2D TMCs)have attracted wide attention owing to their unique material and electrochemical properties.In the 2D TMCs’family,molybdenum chalcogenides as fl agship are the most studied materials and demonstrated the potential as anodes.With the deepening of research on 2D TMCs,another shining member that possesses similar properties to molybdenum chalcogenides,tungsten chalcogenides(WS_(2),WSe_(2),and WTe_(2)),has aroused tremendous attention.Despite many inspiring results,various challenges remain to be further addressed;meanwhile,some results are still unclear and disputed.Herein,this review fi rst introduces their material properties and electrochemical storage mechanisms.Then,we systematically overview the research progress and put forward promoting improvement strategies.Finally,challenges and opportunities that would be future research directions are discussed.

A ZnO decorated 3D copper foam as a lithiophilic host to construct composite lithium metal anodes for Li-O_(2) batteries

Lithium metal batteries(LMBs) with a high theoretical capacity are seen as a type of the most potential energy storage system.Unfortunately,the growth of lithium dendrite,the irreversible side reactions,and the infinite volume alteration still curb the practical utilization of lithium metal anodes,resulting in low Coulombic efficiency(CE) and safety problems,etc.Herein,we synthesize a lithiophilic 3D copper foam host with uniformly distributed nano-flower-like ZnO particles(CuF/ZnO) and obtain the composite lithium metal anode containing the Li_(2)O,LiZn alloy,and pure Li by the infusion of molten Li(CuF/Li_(2)O-LiZn@Li).Benefitting from the advantages of the 3D structure of copper foam and the lithiophilicity of ZnO sites,the composite lithium metal anode can restrain the volume alternation and regulate the uniform deposition of lithium.The symmetrical cells of the composite lithium metal anode have a 1600 h long cycle life with a low polarization voltage of 15 mV,and the Coulombic efficiency can maintain about 97.8% at 1.0 mA·cm^(-2),1.0mAh·cm^(-2).