Spinel-type LiNiMnO (LNMO) can provide high-voltage and high theoretical specific capacity as cathode material for lithium-ion batteries (LIBs), thereby LNMO is particularly suitable for electric/hybrid electric vehicles that require high power. Unfortunately, both serious structural deformation derived from the Jahn-Teller effect of Mn and decomposition of electrolyte during repetitive charge/discharge processes at high operating potential result in fast capacity fade. In this work, lanthanum and fluorine co-doping LiNiLaMnOF (LF-LNMO) is proposed to eliminate its inherent defects. Fluorine can suppress Jahn-Teller effect of Mn by reducing the generation of Mn; La ions in LF-LNMO play a role in solidly riveting atoms together in the structure, and LaMnO coating layer acts as a physical protection barrier suppressing adverse side reactions that may damage battery performance. Thanks to the synergistic effect derived from structural modification of F, the pinning effect of La ions, and LaMnO surface coating interface reconstruction, the LF-LNMO cathode provides the best cycling performance and rate performance among all investigated electrode materials. Such as, LF-LNMO cathode can provide 64.02% capacity retention after the 1000th cycle at 500 mA g and 30 °C, which is much higher than that (25.56%) of the undoped LiNiMnO (P-LNMO). Besides, LF-LNMO electrode also behaves the excellent high-temperature cycling performance. This work provides a new strategy enhancing structural stability of spinel-type Ni/Mn-based oxide and would motivate us to further devise and prepare high power cathode materials for LIBs.

中文翻译：

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La-F共掺杂结合原位集成钙钛矿LaMnO3涂层提高尖晶石型镍锰基锂离子电池高压正极材料的电化学性能

尖晶石型LiNiMnO（LNMO）作为锂离子电池（LIB）正极材料可以提供高电压和高理论比容量，因此LNMO特别适合需要高功率的电动/混合动力汽车。不幸的是，锰的 Jahn-Teller 效应引起的严重结构变形和高工作电位下重复充电/放电过程中电解质的分解都会导致容量快速衰减。在这项工作中，提出了镧和氟共掺杂LiNiLaMnOF（LF-LNMO）来消除其固有的缺陷。氟可以通过减少Mn的生成来抑制Mn的Jahn-Teller效应； LF-LNMO 中的 La 离子在结构中发挥着将原子牢固铆接在一起的作用，而 LaMnO 涂层则充当物理保护屏障，抑制可能损害电池性能的不良副反应。由于F的结构修饰、La离子的钉扎效应以及LaMnO表面涂层界面重建的协同效应，LF-LNMO正极在所有研究的电极材料中提供了最佳的循环性能和倍率性能。例如，LF-LNMO正极在500 mA g-1和30 °C下循环1000次后可以提供64.02%的容量保持率，远高于未掺杂的LiNiMnO (P-LNMO)的容量保持率(25.56%)。此外，LF-LNMO电极还表现出优异的高温循环性能。这项工作提供了一种增强尖晶石型镍锰基氧化物结构稳定性的新策略，并将激励我们进一步设计和制备用于锂离子电池的高功率正极材料。