Enhancing Cycle Performance for Li-Rich Layered Oxides By the Stabilization of Crystal Structure

Li-rich layered oxides (LLO) have been studied as a next generation low-cost and high-capacity positive electrode materials. In LLO, the structural stability must be ensured to reversible Li intercalation. Blocking the tetrahedral site, the path of ions moving from transition metal sites to the lithium layer, may reduce the cation mxing which casuses the structural instability. In addition, introducing electrochemically inactive metal ions in the transition metal layer would stabilize the O-Me-O stacking by binding energy with oxygen which is higher than the transition metals. In this study, LLOs were obtained with and without doping at varous conditions. Doping elements are B and Ge of x mol% with repect of transition metals (Mn, Ni, Co). The effect of doping of is evaluated through the evaluation of the physical and electrochemical characteristics of the synthesized LLOs. Especially, the elelctrochemical cycle stability is throughly studied at various charge cuf-off voltages. The details of evaluation and analysis results will be presented.