High Capacity Prismatic Type Layered Electrode with Anionic Redox Activity as an Efficient Cathode Material and...

A prismatic type layered Na_2/3Ni_1/3Mn_2/3O₂ cathode material for a sodium ion battery is prepared via two different methods viz., the solid state and sol-gel method with dissimilar surface morphology and a single phase crystal structure. It shows tremendous electrochemical chattels when studied as a cathode for a sodium-ion battery of an initial specific discharge capacity of 244 mAh g^-1 with decent columbic efficiency of 98% up to 250 cycles, between the voltage range from 1.8 to 4.5 V (Na⁺/Na) at 0.1 C under room temperature. It is much higher than its theoretical value of 173 mAh g^-1 and also than in the earlier reports (228 m Ah g^-1). The full cell containing this material exhibits 800 mAh g^-1 at 0.1 C and withstands until 1000 cycles with the discharge capacity of 164 mAh g^-1. The surpassing capacity was expected by the anionic (oxygen) redox process, which elucidates the higher capacity based on the charge compensation phenomenon.