A Universal Strategy toward the Precise Regulation of Initial Coulombic Efficiency of Li‐Rich Mn‐Based Cathode Materials

TLDR

Li‑rich Mn‑based cathode materials are promising for high‑energy lithium‑ion batteries, but their low initial Coulombic efficiency hampers commercialization. The study proposes a facile oleic acid‑assisted interface engineering strategy to precisely control the initial Coulombic efficiency and improve the reversible capacity and rate performance of Li‑rich Mn‑based cathodes. The approach employs oleic acid‑assisted interface engineering that introduces cation/anion double defects and an in‑situ surface reconstruction layer, lowering Li⁺ diffusion barriers and generating a self‑built‑in electric field to stabilize surface lattice oxygen. The strategy enables precise ICE tuning from 84.1 % to 100.7 % and delivers a high specific capacity of 330 mAh g⁻¹ at 0.1 C and 250 mAh g⁻¹ at 5 C, while universally improving ICEs of other LRMs and offering a new multistrategy interface engineering approach to enhance overall electrochemical performance.

Abstract

Abstract Li‐rich Mn‐based cathode materials (LRMs) are potential cathode materials for high energy density lithium‐ion batteries. However, low initial Coulombic efficiency (ICE) severely hinders the commercialization of LRM. Herein, a facile oleic acid‐assisted interface engineering is put forward to precisely control the ICE, enhance reversible capacity and rate performance of LRM effectively. As a result, the ICE of LRM can be precisely adjusted from 84.1% to 100.7%, and a very high specific capacity of 330 mAh g −1 at 0.1 C, as well as outstanding rate capability with a fascinating specific capacity of 250 mAh g −1 at 5 C, are harvested. Theoretical calculations reveal that the introduced cation/anion double defects can reduce the diffusion barrier of Li + ions, and in situ surface reconstruction layer can induce a self‐built‐in electric field to stabilize the surface lattice oxygen. Moreover, this facile interface engineering is universal and can enhance the ICEs of other kinds of LRM effectively. This work provides a valuable new idea for improving the comprehensive electrochemical performance of LRM through multistrategy collaborative interface engineering technology.