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

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 LiNi_0.6Co_0.1Mn_0.3O₂ (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.