Electrochemical Performance of SnS@Graphene Composites Prepared by Deep Eutectic Solvent Method

Abstract

SnS material is considered as an attractive anode material to substitute commercial graphite anodes of lithium‐ion batteries (LIBs) due to its large capacity, low cost, and environment‐friendliness. However, the side reactions induced during charge/discharge processes significantly expand the volume of SnS material, limiting its development. Herein, a novel deep eutectic solvent is synthesized with polyethylene glycol and SnCl2·2H2O, and SnS@graphene composites are prepared using a one‐step pyrolytic vulcanization method. The composite material is sandwich‐shaped with graphene sheet layers interspersed with SnS particles. Tests after making them into button cells have shown that the composite electrodes have excellent electrochemical properties: an initial discharge capacity of 1346 mAh g−1 at the current density of 100 mA g−1; outstanding long‐period performance under high current. In the case of 1 A g−1, it still has 421.8 mAh g−1 capacity after 1000 cycles. It also shows superior rate characteristics: under the current density of 5 A g−1, its specific discharge capacity is 343 mAh g−1; the specific discharge capacity increases rapidly to 798 mAh g−1 when the current density returns to 1 A g−1.