Cathodic performance of NiO-coated Li(Ni1/2Mn1/2)O2

Oxide coating helps in the suppression of capacity-fading of oxide cathodes for use in lithium ion batteries. Presently we coated NiO on to Li(Ni1/2Mn1/2,)O-2 and tstudied the cathodic properties. The bare compound was prepared by the mixed hydroxide method and subsequently coated with 3 and 6 wt% of Li(4%)-doped nickel oxide by solution method and characterized by X-ray diffraction and SEM. Cyclic voltammetry of bare and coated samples show clear redox process at 3.65-4.0 V corresponding to Ni2+/4+ and at 4.25-4.4 V due to Mn3+/4+ couples. Galvanostatic charge- discharge cycling was done at a specific current 30mA/g upto 70 cycles in the voltage range 2.5-4.3 V and 2.5-4.3 V vs 2.5-1.5 V vs Li. At the end of 10 cycles, the discharge capacities are 140 +/- 3 mAh/g with 4.3 V cut-off, and aT. in the range 160-185 mAh/g with 4.5 V cut-off for the bare, 3% and 6% NiO- coated compounds. Capacity-fading was observed after 25-30 cycles in all the cases. But, the 6% NiO-coated compound performed better with both 4.3 and 4.5 V cut-off by way of showing stable discharge capacity upto 30 cycles and smaller capacity-fading upto 70 cycles.