Dual-Functional Prelithiation Sacrificial Li6MnO4: Synergistically Enhancing Energy Density and Cycle Life of Lithium-Ion Batteries

Abstract Prelithiation additives have garnered significant interest due to their high lithium supplement capacity and compatibility with established lithium-ion battery manufacturing processes. Nevertheless, leading cathode lithium supplement materials like Li6CoO4, Li5FeO4, and Li2NiO2 are plagued by several limitations, such as high cost, environmental instability, and limited capacity. This work proposes the antifluorite structure Li6MnO4 as a cathode prelithiation additive, elaborates on its structural evolution process, and highlights its advantages of high specific capacity, excellent environmental stability, and low cost. The material delivers an initial lithium supplement capacity as high as 791.5 mAh g–1. In a coin full cell employing LiNi0.6Co0.1Mn0.3O2 (NCM) as the cathode and Si/C as the anode, the specific discharge capacity increased from 163.9 to 168.0 mAh g–1 with the incorporation of Li6MnO4. More notably, the addition of Li6MnO4 substantially enhanced the cycling performance of a pouch cell with an NCM cathode and graphite (GR) anode, increasing the capacity retention from 82.0 to 95.7% after 500 cycles. This study demonstrates that Li6MnO4 is a highly promising lithium compensation material, presenting a new strategy for boosting the energy density and cycling stability of lithium-ion batteries.