Simple synthesis of sandwich-like SnSe2/rGO as high initial coulombic efficiency and high stability anode for sodium-ion batteries

Metal selenides owing to their high theoretical capacity and good conductivity are considered as one of the potential candidates for the anode materials of sodium-ion batteries (SIBs). However, their practical applications are greatly restricted by the poor cycling performances and complicated synthesis methods. In this work, a sandwich-like SnSe2/reduced graphene oxide (rGO) composite with a small amount of rGO (7.3%) is synthesized by a simple one-pot solvothermal technique. The as-synthesized SnSe2/rGO shows improved initial coulombic efficiency (ICE) of 73.7%, high capacity of 402.0 mAh g−1 after 150 cycles at 0.1 A g−1 with a retention of 86.2% and outstanding rate performances. The abundant Sn−O−C bonds of synthesized material not only accelerate the charge transfer at the interface but also enhance the mechanical strength to accommodate volume variation and prevent active material loss during cycling. Moreover, the compact structure leads to thin solid electrolyte interface (SEI) so that high initial coulombic efficiency was obtained. Furthermore, full cells are assembled to test its potential application. This work offers a simple method to synthesize SnSe2/rGO as a candidate anode for SIBs.