Screening and Development of Sacrificial Cathode Additives for Lithium‐Ion Batteries

This work presents a computational screening approach to identify Li‐rich transition‐metal oxide sacrificial cathode additives and provides experimental validation of antifluorite‐structured Li ₆ MnO ₄ as a potential candidate. Initial attempts to synthesize this compound result in low purity (≤40% by weight) owing to close thermodynamic competition with Li ₂ O and MnO at low temperature. However, it is shown that a much higher purity of 85% by weight can be achieved by combining Li excess with rapid cooling from high temperature, which effectively stabilizes the Li ₆ MnO ₄ phase. The synthesized product delivers a high irreversible Li release capacity that exceeds 700 mAh g ⁻¹ by utilizing combined Mn oxidation (Mn ^2+/3+ and Mn ^3+/4+ ) and O oxidation. These results demonstrate that Li ₆ MnO ₄ may therefore be useful as a potential sacrificial cathode additive in Li‐ion batteries and motivate further investigation of other structurally‐related compounds. While attempts were made to synthesize two additional compounds among computationally screened candidates, it was not successful to experimentally realize the two candidates. The difficulty of experimental realization of the newly predicted materials remains a challenge and it is suggested that more efforts need to be devoted to developing computational techniques to precisely predict synthesizability and propose potential synthetic routes of the predicted materials.