Engineering of CuSx@C derived from Cu-MOF as long-life anodes for sodium-ion batteries

Copper sulfides are proved to be good candidates as anode materials for sodium ion batteries due to their abundant resources, moderate cost, and relatively high electrical conductivity . However, poor rate performance and cycling life still hinder their development as anode materials for sodium-ion batteries. Herein, we synthesized carbon-coated copper sulfide nanorod assembled into octahedron composites (CuS x @C) by sulfuration of a Cu-based metal-organic framework (Cu-MOF) under different temperatures. These composites with hierarchical structure exhibited superstable cycling performance as anodes of sodium-ion batteries. The CuS x @C sample obtained under 500 ​°C showed discharge capacity of 208 ​mA ​h ​g - 1  ​at 2 ​A ​g - 1 over 6300 cycles. Porosity and hierarchical stucture facilitate the storage of sodium ion, and carbon-coated structure buffers volume change of anode materials during the electrochemical reaction .