O3-type Na(Fe_1/3Mn_1/3Co_1/3)O_2 as a Cathode Material with High Rate and Good Charge-Discharge Cycle Performance for Sodium-Ion Batteries

O3-Na(Fe_1/3Mn_1/3Co_1/3)O_2 has been reported as a cathode material with a reversible capacity of 84mAh/g. This cathode active material shows excellent electrochemical performance with a high capacity retention of 95.0% after 100 cycles at 1C rate, and a discharge rate capability of 37mAh/g (47% of the initial capacity of 1C rate) at 50C rate. From the results of electrochemical impedance spectroscopy, an increase in reaction resistance was not confirmed between before and after the charge discharge cycle test. TEM observation revealed that the crystal structure change on the surface of O3-Na(Fe_1/3Mn_1/3Co_1/3)O_2 after the charge discharge cycle test was slight, and the change in the crystal structure was small compared with that of the lithium ion battery, so O3-Na(Fe_1/3Mn_1/3Co_1/3)O_2 has high crystal structure stability.