Polygonal WS_2-decorated-graphene multilayer films with microcavities prepared from a cheap precursor as anode materials for lithium-ion batteries

摘要

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-WS2 composite nanofilm with microcavities was obtained. When evaluated as an anode material in a lithium-ion battery, the graphene-WS2 sample (precursor graphene oxide/WS2 mass ratio of 1:4) exhibited high initial specific capacity (similar to 980 mAh g(-1) at 0.1 A g(-1)), optimal cycling performance (similar to 450 mAh g(-1) after 100 cycles at 0.1 A g(-1)), and superior rate capability (similar to 300 mAh g(-1) at 2 A g(-1)). The graphene/WS2 mass ratio influenced the contact between WS2 and graphene and the porous nanofilm structure facilitated the kinetics of lithium-ion diffusion. (C) 2019 Elsevier B.V. All rights reserved.