Tungsten chalcogenides as anodes for potassium-ion batteries

Potassium-ion batteries (PIBs) by virtue of their strong cost competitiveness and similar electrochemical properties to lithium-ion 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 specific 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 two-dimensional 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 flagship 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 (WS₂, WSe₂, and WTe₂), 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 first 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.