Hierarchically porous CoNiO2 nanosheet array films with superior sodium storage performance

Nanostructured transition metal oxides are considered as some of the promising anode materials for rapidly emerging sodium ion batteries. Herein, a hierarchically porous CoNiO2 nanosheet array film is prepared via a low-temperature solvothermal method with subsequent annealing treatment. As a self-supported anode for sodium ion batteries (SIBs), the as-prepared hierarchically porous CoNiO2 nanosheet array film manifests superior sodium storage performance. The film electrode delivers a large reversible capacity of 746.6 mA h g(-1) after 100 cycles at 200 mA g (-1). In particular, a capacity of 419 mA h g(-1) is achieved at a high current density of 1600 mA g (-1), demonstrating a good rate capability.