High-Performance Li-Rich Layered Transition Metal Oxide Cathode Materials for Li-Ion Batteries

Abstract

New stoichiometric Li-rich layered oxides (xLi2MnO3·(1-x)LiMn0.5Ni0.25Co0.25O2 or Li[LiyMn1-y-2zNizCoz]O2) were proposed as high-energy density cathode materials for Li-ion batteries. The correlation between chemical composition of the materials and their structural as well as electrochemical performances is discussed. It was found that all synthesized materials crystalize within C2/m space group with existence of superstructure and possess nanometric spherical-shaped morphology. The analysis of the charge/discharge tests shows that Li[Li0.2Mn0.6Ni0.1Co0.1]O2 electrode delivers nearly 350 mAh·g−1 for the first discharge process and 250 mAh·g−1 for following cycles. The investigation of the kinetics of the electrode reactions by means of CV and EIS methods confirmed that Li[Li0.2Mn0.6Ni0.1Co0.1]O2 exhibits highest lithium diffusion coefficients, what with obtained electrochemical cycling tests suggest optimal chemical composition of this material ensuring high energy density along with long-term endurance.