Rapid lithium‐ion insertion/extraction and migration behavior of Na ₂ WO ₄ ‐encapsulated lithium‐rich layered oxide cathode

Abstract

Abstract Due to the low cost, high working voltage and high storage capacity, Li‐rich Mn‐based layered compounds show promise as the cathode materials for lithium‐ion batteries (LIBs). However, the side reactions at the solid–liquid interface of the cathode will lead to rapid capacity decay and inferior rate performance. Herein, this article proposes a liquid‐phase dispersion strategy to introduce a Na 2 WO 4 layer on the Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 cathode, which can reduce the side effects between raw materials and electrolyte and promote the insertion/extraction rate of Li + , thus enhancing the material stability and rate performance. As a result, the capacity retention rate is 96.9% after 200 cycles under 2C. Moreover, the capacities are 177.5, 149.5, 111.1 and 58.3 mAh·g −1 at 1C, 2C, 5C and 10C, implying a superior fast charging performance. The exceptional performance can be ascribed to both the increased conductivity and enhanced structural stability of the cathode material. What’s more, based on the investigation of ion insertion/extraction behavior in electrode materials and the ion migration kinetics in the electrolyte, this study suggests that coating Li‐rich Mn‐based materials with Na 2 WO 4 can be a promising strategy to improve their performance in LIBs.