High capacity prismatic type layered electrode with anionic redox activity as an efficient cathode material and PVdF/SiO2 composite membrane for a sodium ion battery

Abstract

A prismatic type layered Na2/3Ni1/3Mn2/3O2 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.