A Structure Self-Healing Li-Rich Cathode Achieved by Lithium Supplement of Li-Rich LLZO Coating

Abstract

Lithium-rich manganese-based cathode materials (LLMO) are considered as the promising candidates for realizing high energy density lithium-ion batteries. However, the severe structure deterioration and capacity fading hinder their large-scale application. Herein, an innovative electrochemical lithium supplement strategy is put forward to inhibit the structure collapse and enhance the cycling stability of Lithium-rich manganese-based cathodes. Besides, combining with the superior Li-ion conductor Li_6.25La₃Zr₂Al_0.25O₁₂ (LLZAO), remarkable rate capability is achieved. As a result, a capacity retention of 95.7% after 300 cycles at 1.0 C (1.0 C = 200 mA g⁻¹), as well as a stable cycling at 5.0 C with discharge capacity of 136.9 mAh g⁻¹, are harvested. Moreover, the excess lithium ions in LLZAO mitigate the spinel-like phase transformation via inserting into the lithium layer and stabilizing the cathode structure. In addition, the lithium ions migration behavior in the elaborated cathode is thoroughly expounded and the correlation between diffusion kinetics and LLZAO is revealed. These findings boost the updating of LLMO and pave a new pathway for stabilizing LLMO structures.