In Situ Carbon-coated Ni0.85Se@C Composite with High Performance for Sodium-ion Batteries

Ni(benzimidazole)(2-methylimidazole) with two-dimensional structure is used as a self-template to synthesize carbon-coated Ni0.85Se (Ni0.85Se@C) composites. Ni0.85Se@C composites display a thin nanosheet structure (∼20 nm) with macropores (∼200 nm), which can effectively reduce the volume change. The carbon network can improve the electrical conductivity of the electrode material. When evaluated as anode material for sodium ion batteries (SIBs), Ni0.85Se@C composites deliver an excellent reversible capacity of 405 mA h g−1 at 200 mA g−1 after 100 cycles and a good rate performance with a capacity of 200 mA h g−1 at 3.0 A g−1. Ni(bim)(2-mim) with two-dimensional structure is used as self-template to synthesize carbon-coated Ni0.85Se composites (Ni0.85Se@C) with numerous thin (∼20 nm) nanosheets and pores (∼200 nm), which effectively reduce the huge volume change. Ni0.85Se@C nanosheets were evaluated as anode material of SIBs, which deliver an excellent electrochemical performance.