Eliminating oxygen releasing of Li-rich layered cathodes by tuning the distribution of superlattice domain

Abstract

Li-rich layered cathodes suffer from oxygen releasing with the undesired rapid performance decay at subsequent cycles. Herein, we propose a strategy on tuning the distribution of Li2MnO3-like domains to eliminate oxygen evolution. The distribution regulation is turned by the Li+ concentration in the early synthesizing stage, which is caused by the altered participation of Co3+ in the Li2MnO3-like configuration. The detailed local structural evolution is revealed by corresponding extended X-ray absorption fine structures. As calculated and simulated from synchrotron X-ray diffraction results and FAULTS program, the Li2MnO3-like domain can be well-dispersed in the lattice. No oxygen release with little carbon dioxide gas is detected by operando differential electrochemical mass spectrometry. The dispersed Li2MnO3-like microstructures can withstand more stress induced by structural distortion as confirmed by operando X-ray diffraction. The as-fabricated 10.5 Ah pouch cell with Li metal anode exhibits a specific energy density of 504 Wh kg−1 on the basis of cell mass. This work provides an effective approach to suppress oxygen releasing for high-energy-density lithium secondary batteries.