Tin (IV) Oxide (SnO₂) Modifed LiNi_0.8Co_0.2O₂ Cathode Material for Lithium Ion Batteries

Abstract

Synthesis of positive electrode materials for lithium ion batteries (LIB) plays a major role in battery performance. In this study, we first investigated the effect of chelating agents and calcination temperature on the production of LiNi0.8Co0.2O2 cathode material. Then, by using mechanical mixing and sol-gel methods, tin oxide was introduced in the LiNi0.8Co0.2O2 powder to enhance the electrochemical performance. The effects of chelating agents (citric acid, oxalic acid, adipic acid), calcination temperature (600-800 °C, @10 hours) and the tin oxide presence on the LiNi0.8Co0.2O2 powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer, Emmmett and Teller (BET) analyses. Galvonastatic tests were performed in between 3-4.2 V at various C rates (0.2, 0.5, 1C).The powders produced by using adipic acid as chelating agent at 700 °C showed higher capacity and better electrochemical properties than those of powders synthesized by oxalic and citric acid. And sol-gel modified powders had higher initial capacity and better capacity retention than the mechanically modified and the bare powders. Sol-gel modified powders had more stable cycle characteristic and they had not shown immediate capacity fall even at higher C rates where they kept their capacity above 140 mAh/g even after 50 cycles.