Layered lithium-rich manganese oxides (LMO) are promising cathode materials for high-energy density lithium-ion batteries due to their high specific capacity and working potential. However, serious voltage decay and undesirable cycle stability are big obstacles that hinder their industrialization and application. Herein, an innovative and industrially valuable strategy of constructing composite coatings and oxygen vacancies on the LMO surface is put forward to suppress voltage decay and enhance the cycling stability of LMO by precisely modulating NaBH treatment. The synergistic effect of surface spinel coating, NaBOcoating, and oxygen vacancies effectively inhibits the release of oxygen, impedes the occurrence of side reactions at the interface, inhibits the migration and dissolution of transition metals, suppresses the irreversible structure transformation and improves the reversibility of redox reaction. The capacity retention of the NaBH-treated LMO material maintains 100 % after 200 cycles at 0.5C, as well as stable cycling at 2C with a discharge capacity of 180 mAh g harvested. Moreover, the voltage decay is significantly suppressed by NaBH modification, especially the NaBH-0.5 % sample exhibits a mere voltage decay of 1.73 mV per cycle in the 200 cycles. This study provides significant insights into the development of LMO cathodes with long-cycle performance.

中文翻译：

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调节表面结构以抑制高稳定富锂氧化物阴极的电压衰减


层状富锂锰氧化物（LMO）因其高比容量和工作潜力而成为高能量密度锂离子电池的有前途的正极材料。然而，严重的电压衰减和不良的循环稳定性是阻碍其产业化和应用的一大障碍。在此，提出了一种在 LMO 表面构建复合涂层和氧空位的创新且具有工业价值的策略，通过精确调节 NaBH 处理来抑制电压衰减并增强 LMO 的循环稳定性。表面尖晶石涂层、NaBO涂层和氧空位的协同作用，有效抑制氧的释放，阻碍界面副反应的发生，抑制过渡金属的迁移和溶解，抑制不可逆结构转变，提高氧化还原的可逆性反应。经过 NaBH 处理的 LMO 材料在 0.5C 下循环 200 次后容量保持率保持在 100%，并且在 2C 下稳定循环，放电容量为 180 mAh g。此外，NaBH 改性显着抑制了电压衰减，特别是 NaBH-0.5% 样品在 200 个循环中每个循环仅表现出 1.73 mV 的电压衰减。这项研究为开发具有长循环性能的 LMO 阴极提供了重要的见解。