Structurally Modulated Advanced Na-Doped Antifluorite-Based Pre-Lithiation Reagents Towards Superior Lithium Compensation

Antifluorite-type Li5FeO4 (LFO) cathode prelithiation materials are considered to exhibit one of the most promising prelithiation materials owing to high irreversible capacity, the great abundance and appropriate redox potential of Fe. Despite these advantages, the practical of LFO still is hampered lithium compensation upon incomplete delithiation and susceptibility to air-induced degradation. In this work, we ingeniously proposed that implants sodium substitution at the lithium sites of LFO (LFO-Na), which enhances the lattice oxygen and triggers the anionic redox activity of the material. Specifically, the LFO-Na exhibits superior lithium compensation of 763.8 and 584.2 mAh g-1 at 0.1 and 1 C, which is higher than 677.6 and 362.5 mAh g-1 of LFO. Moreover, LFO-Na exhibits good air stability, retaining a capacity up to 531.0 mAh g-1 after exposing to 20% humidity air for 8 h. Furthermore, based on LFO-Na cathode prelithiation materials, the initial capacity of the graphite‖NCM811 pouch cell is 209.4 mAh g⁻¹, with a high-capacity retention of 88.7% at 0.5 C after 200 cycles. This work delivers novel insights into facilitating Li+ migration to improve the lithium compensation of LFO.