Cu2GeS3 derived ultrafine nanoparticles as high-performance anode for sodium ion battery

Abstract

Germanium based sulfides are potentially attractive as anode material for sodium ion batteries but rarely investigated. Herein, we firstly investigated Na+ storage properties of pristine Cu2GeS3 (PCGS) and found an effective strategy to improve its performance by a single lithiation/delithiation cycle obtaining ultrafine nanoparticle copper germanium sulfide (NCGS). The lithiation/delithiation process leads to the formation of a stable Li-containing solid electrolyte interphase film and a significant improvement of sodiation kinetics. Therefore, the NCGS anode delivers favorable capacity retention and better rate capability compared with that of a PCGS whether in the half cell or in the full cell, showing great promise for energy storage application.