Polygonal WS2-decorated-graphene multilayer films with microcavities prepared from a cheap precursor as anode materials for lithium-ion batteries

In this study, the water-evaporation-induced assembly of a graphene oxide-ammonium metatungstate hydrate multilayer film was developed. After chemical reduction and high-temperature sulfurization, a graphene-WS 2 composite nanofilm with microcavities was obtained. When evaluated as an anode material in a lithium-ion battery, the graphene-WS 2 sample (precursor graphene oxide/WS 2 mass ratio of 1:4) exhibited high initial specific capacity (∼980 mAh g −1 at 0.1 A g −1 ), optimal cycling performance (∼450 mAh g −1 after 100 cycles at 0.1 A g −1 ), and superior rate capability (∼300 mAh g −1 at 2 A g −1 ). The graphene/WS 2 mass ratio influenced the contact between WS 2 and graphene and the porous nanofilm structure facilitated the kinetics of lithium-ion diffusion.