Electrochemical Behavior of Layered LiNi_1/2Mn_1/2O₂ for Lithium-Ion Batteries

Abstract

The active material of cathode in Li-ion batteries, LiNi_1/2Mn_1/2O₂, was synthesized by sol-gel and molten-salt methods. The sol-gel precursors of Mn²⁺ and Ni²⁺ were prepared by using polyvinyl alcohol (PVA) as chelating agent and electrochemical properties of the cathode active material were characterized by FE-SEM, XRD and Charge-Discharge Cycler. It was identified from Rietveld refinement of XRD data that layered LiNi_1/2Mn_1/2O₂ materials were synthesized and the Li⁺ and Ni²⁺ ions were coexisted in 3a and 3b sites. Electrochemical cells using LiNi_1/2Mn_1/2O₂ were tested at the voltage range between 2.0 and 4.8 V and at the specific current density of 40 mA g^-1. It was also found that LiNi_1/2Mn_1/2O₂ included acetylene black of 40 wt% showed higher rechargeable capacity than that of 15 wt%.