Guo Weibin, Zhang Chenying, Zhang Yinggan, Lin Liang, He Wei, Xie Qingshui, Sa Baisheng, Wang Laisen, Peng Dong-Liang
State Key Laboratory of Physical Chemistry of Solid Surface Fujian Key Laboratory of Materials Genome Collaborative Innovation Center of Chemistry for Energy Materials College of Materials, Xiamen University, Xiamen, 361005, China.
Multiscale Computational Materials Facility College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350100, China.
Adv Mater. 2021 Sep;33(38):e2103173. doi: 10.1002/adma.202103173. Epub 2021 Aug 1.
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 at 0.1 C, as well as outstanding rate capability with a fascinating specific capacity of 250 mAh g 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.
富锂锰基正极材料（LRMs）是高能量密度锂离子电池的潜在正极材料。然而，低初始库仑效率（ICE）严重阻碍了LRM的商业化。在此，提出了一种简便的油酸辅助界面工程，以精确控制ICE，有效提高LRM的可逆容量和倍率性能。结果，LRM的ICE可以从84.1%精确调整到100.7%，在0.1 C下获得了330 mAh g的非常高的比容量，以及在5 C下具有250 mAh g的迷人比容量的出色倍率性能。理论计算表明，引入的阳离子/阴离子双缺陷可以降低锂离子的扩散势垒，原位表面重建层可以诱导自建电场来稳定表面晶格氧。此外，这种简便的界面工程具有通用性，可以有效提高其他种类LRM的ICE。这项工作为通过多策略协同界面工程技术提高LRM的综合电化学性能提供了一个有价值的新思路。
