Lithium-rich manganese-based cathode (LRM) is considered to be the most promising cathode materials for next-generation lithium-ion batteries due to its high energy density. However, the low initial coulombic efficiency and poor rate performance are severe problems in the commercialization of LRM. Herein, we use an ascorbic acid (VC) modulation strategy to create spinel-carbon composite coatings and dual defects (oxygen vacancies, stack faults) on the surface of LRM. The composite surface coating and defects play a synergistic role in inhibiting interfacial side reactions, enhancing structural stability, and improving electrical conductivity as well as lithium-ion diffusion kinetics. As a result, the modified LRMs exhibit a specific capacity of 251.7mAh/g with an improved initial coulombic efficiency (ICE) of 82.3 % (pristine 72.9 %), enhanced rate capability (135 mAh/g at 5C), and long-term cyclability of 90 % retention after 200 cycles compared with the pristine (78 % retention after 200 cycles). The performance improvement of the modified LRMs is attributable to the composite coating and the dual defects, which ensure the LRM with a more stable structure (smaller volume change of 2.4 % compared with the original sample of 3.65 %). This strategy provides an efficient and environmentally friendly idea of surface modification for boosting the electrochemical performance.

中文翻译：

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表面调制诱导氧空位/堆叠故障和尖晶石-碳复合涂层朝向高性能富锂锰基阴极


富锂锰基正极 （LRM） 因其高能量密度而被认为是下一代锂离子电池最有前途的正极材料。然而，初始库仑效率低和倍率性能差是 LRM 商业化的严重问题。在此，我们使用抗坏血酸 （VC） 调制策略在 LRM 表面创建尖晶石-碳复合涂层和双重缺陷（氧空位、堆栈故障）。复合表面涂层和缺陷在抑制界面副反应、增强结构稳定性、提高导电性和锂离子扩散动力学方面发挥协同作用。因此，改性的 LRM 表现出 251.7mAh/g 的比容量，初始库仑效率 （ICE） 提高了 82.3%（原始 72.9%），提高了倍率能力（5C 时为 135 mAh/g），与原始相比，200 次循环后的长期可循环性为 90%（200 次循环后保留 78%）。改性 LRM 的性能改进归因于复合涂层和双重缺陷，这确保了 LRM 具有更稳定的结构（与原始样品的 3.65 % 相比，体积变化更小，为 2.4%）。该策略提供了一种高效且环保的表面改性理念，以提高电化学性能。