Co-doped NiO nanoflake arrays toward superior anode materials for lithium ion batteries

Co-doped NiO nanoflake arrays with a cellular-like morphology are fabricated by low temperature chemical bath deposition. As anode material for lithium ion batteries (LIBs), the array film shows a capacity of 600 mAh g⁻¹ after 50 discharge/charge cycles at low current density of 100 mA g⁻¹, and it retains 471 mAh g⁻¹ when the current density is increased to 2 A g⁻¹. Appropriate electrode configuration possesses some unique features, including high electrode-electrolyte contact area, direct contact between each naonflake and current collector, fast Li⁺ diffusion. The Co²⁺ partially substitutes Ni³⁺, resulting in an increase of holes concentration, and therefore improved p-type conductivity, which is useful to reduce charge transfer resistance during the charge/discharge process. The synergetic effect of these two parts can account for the improved electrochemical performance.