Nitrogen-Doped Graphene-Supported Straw-Like CoSe2 for Rapid and Stable Sodium-Ion Storage

Cobalt diselenide (CoSe2) materials exhibit significant potential in sodium-ion batteries (SIBs) owing to their high theoretical specific capacity and excellent cycling stability. However, the conductivity and volume expansion of CoSe2 limit its rate performance and cycling stability. Herein, a nitrogen-doped reduced graphene oxide (N-rGO) supported straw-like CoSe2 anode material (CoSe2/N-rGO) is synthesized via a hydrothermal method. Experimental results show that nitrogen doping improves the conductivity and structural stability of CoSe2/N-rGO, enabling excellent rate performance (311.75 mAh g–1 at 10 A g–1) and high cycling stability (356.78 mAh g–1 after 1000 cycles at 1 A g–1). Notably, the CoSe2/N-rGO||NVP full cell exhibits a capacity of 117.4 mAh g–1 at 0.1 C, approaching 98.7% of the calculated maximum for NVP (118 mAh g–1). This approach offers new insights and valuable guidance for the structure of efficient electrode materials for energy storage systems.