Accelerating the decomposition kinetics of Li₅FeO₄ for mitigating potential risks in practical applications

Developing cathode prelithiation technology to offset irreversible active lithium loss is essential for high-energy-density batteries. Antifluorite Li-rich Li₅FeO₄ (LFO) is a promising cathode prelithiation agent, owing to its high theoretical capacity and a suitable voltage window. However, industrial observation reveals that when LFO loading exceeds a critical threshold, graphite‖LiFePO₄ (Gr‖LFP) pouch cells exhibit continuous gas evolution during storage and cycling, posing a latent safety hazard that hinders further application. Here, we systematically elucidate that the kinetic mismatch between LFO and LFP results in the incomplete decomposition of LFO, leaving residual reactive oxygen species that drive parasitic side reactions. Furthermore, we tailor the band structure and oxygen oxidation pathway of LFO via Mn doping to obtain LFMO, thereby enhancing electronic conductivity and stabilizing oxygen electron holes to accelerate decomposition kinetics. Consequently, the prelithiation capacity of LFMO increases to 752.5 mAh g^-1 (a 7.8% improvement). Incorporating 2.7 wt% LFMO into pouch cells increases energy density by 2.4% and markedly suppresses gassing, paving the way for high-energy-density and inherently safe power batteries.