Layered metal chalcogenide based anode materials for high performance sodium ion batteries: A review

Sodium ion batteries (SIBs), as an attractive alternative of lithium-ion batteries (LIBs), have drawn great attention due to the abundant sodium resources as well as low cost. Searching for promising anode materials is one of the key issues for the development and application of SIBs. Layered metal chalcogenides (MS2, M = Mo, V, W, Sn) always possess high theoretical capacities with excellent structural stability, which have been considered as a promising anode material family for SIBs. However, their low conductivity, large volume expansion, and slow electrochemical kinetics always result in poor cycling stability and bad rate capability, severely limiting its application in SIBs. In this review, numerous efficient strategies, such as nanostructure designing, electrolyte selecting, voltage cutting off, and combination of MS2 with non-carbon/carbon materials, proposed to enhance the electrochemical performance are introduced in details. Consequently, these strategies can effectively generate more active sites for Na+ storage, shorten Na+ diffusion path, enhance conductivity, or relieve volume expansion. However, most of strategies are too complex to limit their practical applications. Thus, it is still full of challenges to use facile methods for the fabrication of suitable anode materials in the development of SIBs with outstanding electrochemical performance.