Spinel LiNi0.5Mn1.5O4 (LNMO) suffers from Mn3+-induced degradation due to thermodynamic phase separation. Herein, we report the preincorporation of a LixNi1–xO (LNO) phase to regulate oxygen behavior through a dual-regulation strategy (interfacial charge modulation and kinetic facilitation of oxygen diffusion). Differential charge and Bader analyses confirm that the presence of LNO increases the covalency of the Mn–O bond and suppresses the release of oxygen. In situ EIS-DRT shows improved interfacial ion transport and suppressed side reactions. The optimized composite finally showed 54.2% less Mn3+, 76.2% higher oxygen vacancy energy, and 98.0% capacity retention over 300 cycles. This work will prove to be an overarching approach to stabilizing metastable cathodes by utilizing deleterious phases.
Wang et al. (Thu,) studied this question.