The materials of LiNi_1/2Mn_1/2O₂ are synthesized using PVA-assisted sol-gel and molten-salt synthesis. LiNi_1/2Mn_1/2O,sub>2 synthesized at 600 ℃ for 24h was performed the discharge capacity of about 90 and 180 mAh/g. We increased the amount of acetylene black from 15 wt% to 40 wt% in cathode. The sample included 40 wt% of acethylene black showed the higher discharge capacity of about 165 mAh/g after 40 cycles. In case of LiNi_1/2Mn_1/2O₂ heated at 900 ℃ for another 3h after the material was synthesized at 600 ℃ for 24h, it contained 40 wt% of acetylene black performed higher discharge capacity, about 220 mAh/g after 70 cycles.