Study on the effect of Ti substitution on the structural and electrochemical characteristics of O3-NaNi1/3Mn(1/3-x)Fe1/3TixO2 cathode materials

Here, O3-type NaNi1/3Mn(1/3-x)Fe1/3TixO2 (x=0, 0.005, 0.01) materials were synthesized using a combination of ball milling and spray drying. The most favorable doping proportion of NaNi1/3Mn(1/3-x)Fe1/3TixO2 (x=0.005, NFM-Ti0.005) was determined. The first discharge capacity of NFM-Ti0.005 is 130.8 mAhg-1 at 1C, and the retention rate is 86.17% after 200 cycles. Even at a rate of 5C, the initial capacity reached 112.71 mAhg-1, and after 200 cycles, it was still at 96.69 mAhg-1, with a capacity reduction rate of only 11.61%. Moreover, the first discharge capacity of NFM-Ti0.005 at 4.3 V reached 157.5 mAhg-1 as well as a capacity retention rate of 80.4%. The synthetic method employed as well as the electrochemical characterisation determined the practicality of Ti doping in O3-type sodium-ion batteries.