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

Abstract

© The Author(s) 2019. Published by ECS. New stoichiometric Li-rich layered oxides (xLi 2 MnO 3 ·(1-x)LiMn 0.5 Ni 0.25 Co 0.25 O 2 or Li[Li y Mn 1-y-2z Ni z Co z ]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[Li 0.2 Mn 0.6 Ni 0.1 Co 0.1 ]O 2 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[Li 0.2 Mn 0.6 Ni 0.1 Co 0.1 ]O 2 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.