Emerging WS2/WSe2@graphene nanocomposites: synthesis and electrochemical energy storage applications

In recent years, tungsten disulfide (WS2) and tungsten selenide (WSe2) 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 WS2 and WSe2 to form a WS2/WSe2@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 WS2/WSe2@graphene nanocomposites in electrochemical energy storage applications is summarized. Furthermore, various methods for the synthesis of WS2/WSe2@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 WS2/WSe2@graphene nanocomposites in electrochemical energy storage applications are proposed.