Tailoring hollow microflower-shaped CoSe2 anodes in sodium ion batteries with high cycling stability.

Hollow microflower-shaped CoSe2 particles were successfully constructed and further evaluated as an anode material for sodium-ion batteries. It yielded a large discharge capacity of 220 mA h g-1 and ultralong cycle life of 1690 cycles at 1 A g-1. This ultralong cycle life can be attributed to a surface-controlled pseudocapacitive behavior and resulting rapid electron/sodium ion transport.