TiO2–LiF composite coating for improving NCM622 cathode cycling stability: one-step construction

Abstract

The Ni-rich NCM622 is a promising cathode material for future high energy lithium ion batteries, but unstable electrochemical performance of NCM622 hinder its large scale commercial application. The cycling peformance of nickel-rich LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) cathode materials can be improved by surface coating. Here, a one-step approach based on TiF₄ is used to successfully manufacture modified NCM622 cathode materials with a TiO₂–LiF coating. The TiO₂–LiF coated NCM622 preserves 79.7% capacity retention which is higher than the pure NCM622 (68.9%) at 1C after 200 cycles within 2.7–4.3 V. This material serves as the cathode for lithium-ion batteries (LIBs). The uniform TiO₂–LiF coating layer can alleviate structural degradation brought on by unfavorable side reactions with the electrolyte has been validated. TiO₂–LiF coated on NCM622 cathode materials can be modified easily by one-step approach.