SnSe/Cu₂SnSe₃ Heterojunction Structure with High Initial Coulombic Efficiency for Lithium-Ion Battery Anodes

Abstract

Due to high theoretical specific capacity and abundant reserves, tin selenide-based materials have received tremendous attentions in the fields of lithium-ion batteries. Nevertheless, the huge volume changes during insertion/de-intercalation processes deteriorate the Coulombic Efficiency greatly. In order to solve it, the researchers have made great efforts by means of controlling nanoparticles granularity, carbon coating, ion doping et al. In this study, SnSe/Cu2SnSe3 heterojunction nanocomposites were synthesized by solvo-thermal method. The resulting SnSe/Cu2SnSe3 is a three-dimensional flower-like hierarchical nanostructure composed of nanoscale thin lamellae of a thickness of 8-12 nm. The unique nanostructure could shorten the diffusion path of lithium ions and expedite charge transfer, and therefore enhance the reaction kinetics. Compared with SnSe, the initial Coulombic efficiency of SnSe/Cu2SnSe3 is raised from 59% to 90% as the anode material of lithium-ion batteries.