Ni-rich Co-free cathodes have attracted extensive attention for high-energy–density lithium ion batteries (LIBs). However, structural and interfacial instability in these cathodes accelerates capacity degradation under high-voltage operation. Herein, Ni-rich Co-free In/Sn dual-element modified cathode (InSn-LiNiMnAlO InSn-NMA85) was synthesized through a one-step sintering strategy. Dual-element doping along with the in-situ induced LiInO interphase synergistically prolongs the cycle life of the Ni-rich Co-free cathode under high voltage (≥4.5 V) as well as high temperature (≥45 °C). Comprehensive characterizations combined with DFT calculation confirm that In/Sn dual-element modification effectively increases Li/Ni mixing energy and oxygen release energy, stabilizes the lattice structure, and improves the electrochemical performance. Meanwhile, in-situ formed coating of LiInO effectively protects the cathode from redundant cathode-electrolyte side reactions, preserves the layered phase, and further inhibits the generation of microcracks after cycles. The modified cathode maintains superior capacity retention of ∼ 100 % and ∼ 90 % within the voltage range of 2.7–4.5 V at 30 °C and 45 °C, respectively, after 100 cycles. The modification strategy enables the Ni-rich Co-free layered NMA85 cathode to deliver comparable battery performance with NCM and NCA cathodes, which provides promising approaches for the application of Ni-rich Co-free cathode in 4.5 V-class high-energy–density LIBs.

中文翻译：

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通过双元素改性设计无钴富镍正极材料以实现 4.5 V 级高能量密度锂离子电池


富镍无钴正极引起了高能量密度锂离子电池（LIB）的广泛关注。然而，这些正极的结构和界面不稳定性加速了高电压操作下的容量退化。在此，通过一步烧结策略合成了富镍无钴In/Sn双元素改性阴极（InSn-LiNiMnAlO InSn-NMA85）。双元素掺杂与原位诱导的 LiInO 中间相协同延长富镍无钴正极在高电压（≥4.5 V）和高温（≥45 °C）下的循环寿命。综合表征结合DFT计算证实，In/Sn双元素改性有效提高了Li/Ni混合能和氧释放能，稳定了晶格结构，提高了电化学性能。同时，原位形成的LiInO涂层有效地保护了正极免受多余的正极-电解质副反应的影响，保留了层状相，并进一步抑制了循环后微裂纹的产生。经过 100 次循环后，在 30 °C 和 45 °C 的电压范围内，改进的正极在 2.7–4.5 V 的电压范围内分别保持了 ∼ 100 % 和 ∼ 90 % 的优异容量保持率。该改性策略使富镍无钴层状NMA85正极能够提供与NCM和NCA正极相当的电池性能，这为富镍无钴正极在4.5 V级高能量密度中的应用提供了有前途的方法LIB。