Interface coupling 2D/2D SnSe2/graphene heterostructure as long-cycle anode for all-climate lithium-ion battery

Abstract

Tin selenide (SnSe2) is an ideal anode in lithium-ion batteries (LIBs) owing to its high theoretical capacity and high conductivity for both electrons and ions. Herein, we design a unique heterostructure with 2D SnSe2 nanosheets supported on graphene, where the chemical coupling effect is formed between graphene and SnSe2, working as a cushion to buffer the volume change of electrodes. The 2D/2D SnSe2/graphene heterostructure has a reversible capacity of 490.9 mAh g−1 at a current rate of 0.1C, with an ultra-long cycling stability with capacity retention of 59.3% after 1500 cycles at 0.5C, and can well work at temperatures from −30 to 70 °C. Ex situ X-ray diffraction reveals that the long-term capacity is ascribed to reversible reaction of generating LixSn with Sn and Li, and the capacity loss is attributed to the irreversible reaction with the appearance of Li2Se. The remarkable electrochemical performances, such as high specific capacity, acceptable rate feature, ultra-long cycling life, and wide temperature operation, make the SnSe2/grapheme heterostructure very potential for all-climate LIBs.