Enabling High-Voltage Stability: The Universal Application of Sacrificial Li5FeO4 in Lithium-Ion Batteries

Abstract

Mitigating irreversible lithium loss at the anode through cathode-incorporated Li supplement additives is essential for enabling high-energy Li-ion batteries (LIBs). Antifluorite-type Li5FeO4 (LFO) has been widely studied as a sacrificial cathode additive due to its high Li donor capacity and favorable environmental adaptability. However, the impact of incorporating LFO on the performance of various battery systems under different voltage windows has not been systematically investigated. Herein, the LFO synthesized via a pellet firing method delivers a high capacity of 679 mAh g−1 and demonstrates promising compatibility with LiFePO4 (LFP) or single-crystal LiNi0.8Co0.1Mn0.1O2 (SNCM) under diverse conditions. In situ XRD analysis monitors the crystal structure transformation and reveals the delithiation mechanism of LFO. Electrochemical performance demonstrates that LFO incorporation significantly enhances the discharge capacity (153.4 mAh g−1 at 1 C) and extends the cycle lifespan (>1000 cycles) in LFP cathodes while suppressing the H2 → H3 phase transition in SNCM systems, thus preventing microcrack formation during cycling. Additionally, the influence of LFO on the SNCM system under high voltage and wide temperature is also investigated. This study positions LFO as a scalable sacrificial cathode additive for next-generation batteries, confirming its universal utility in enhancing performance across disparate cathode systems.