Emerging WS 2 /WSe 2 @graphene nanocomposites: synthesis and electrochemical energy storage applications

In recent years, tungsten disulfide (WS 2 ) and tungsten selenide (WSe 2 ) have emerged as favorable electrode materials because of their high theoretical capacity, large interlayer spacing, and high chemical activity; nevertheless, they have relatively low electronic conductivity and undergo large volume expansion during cycling, which greatly hinder them in practical applications. These drawbacks are addressed by combining a superior type of carbon material, graphene, with WS 2 and WSe 2 to form a WS 2 /WSe 2 @graphene nanocomposites. These materials have received considerable attention in electro-chemical energy storage applications such as lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and supercapacitors. Considering the rapidly growing research enthusiasm on this topic over the past several years, here the recent progress of WS 2 /WSe 2 @graphene nanocomposites in electrochemical energy storage applications is summarized. Furthermore, various methods for the synthesis of WS 2 /WSe 2 @graphene nanocomposites are reported and the relationships among these methods, nano/microstructures, and electrochemical performance are systematically summarized and discussed. In addition, the challenges and prospects for the future study and application of WS 2 /WSe 2 @graphene nanocomposites in electrochemical energy storage applications are proposed. Graphical Abstract