Preparation and Evaluation of New Cathode Materials for Rechargeable Lithium Battery with 5V

Abstract

LiMe_1/6Ni_2/6Mn_9/6O₄(Me=Cr, Fe, Co, Ni, Cu, Zn) were prepared and tested as 5V cathode materials. When using Ti mesh current collector, these cathode materials did not exhibit a good performance, due to a corrosion of Ti mesh current collector. On the other hand, the LiMe_1/6Ni_2/6Mn_9/6O₄ materials showed the excellent rechargeability and relatively high discharge capacity when using Al current collector. The discharge capacity and rechargeability of LiMe_1/6Ni_2/6Mn_9/6O₄ strongly depended on the kind of the substituted ions. The best performance was obtained when a part of Mn ions in LiMn₂O₄ crystal was substituted by Ni ions (LiNi_0.5Mn_1.5O₄). The discharge capacity was more than 130 mA h g^-1 and the rechargeability was 100%. The coulombic efficiency was about 97 %. The average discharge potential was 4.75 V vs. Li/Li⁺.