Interfacial Regulation via Synergistic Dual-Additive Enabling 310 W h kg ⁻¹ LFP-Based Lithium Metal Batteries

Integrating LiFePO 4 (LFP) with lithium metal anodes represents a viable way toward balancing energy density and safety, which necessitates an electrolyte capable of forming an ideal interphase to ensure sufficient Coulombic efficiency. Herein, through the synergistic effect of LiNO 3 and fluoroethylene carbonate as additives, a robust solid electrolyte interphase (SEI) enriched with Li 3 N and LiF is constructed. Therefore, the optimized SEI enables LFP-based lithium metal batteries (LMBs) to steadily operate at 3C, with a 300 mA h Li∥LFP pouch cell sustaining over 370 cycles. Furthermore, a 5 A h pouch cell achieves an energy density of 310 W h kg −1 over 100 cycles, surpassing commercial lithium-ion batteries (LIBs). Safety tests confirm resistance to hot box (200 °C) and nail penetration, with an elevated thermal runaway trigger temperature compared to LIBs. Such cooperative SEI modification provides an effective strategy for constructing practical LFP-based LMBs with enhanced cycling and safety performance.