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-LiNi0.85Mn0.09Al0.06O2, InSn-NMA85) was synthesized through a one-step sintering strategy. Dual-element doping along with the in-situ induced LiInO2 interphase synergistically prolongs the cycle life of the Ni-rich Co-free cathode under high voltage (≥4.5V) as well as high temperature (≥45°C). Comprehensive characterizations combined with DFT calculation confirm that In/Sn dual-element modification effectively increases Li?/Ni2? mixing energy and oxygen release energy, stabilizes the lattice structure, and improves the electrochemical performance. Meanwhile, in-situ formed coating of LiInO2 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.
本文通訊作者為上海大學張久俊院士和清華大學曹譯丹教授，第一作者為上海大學-清華大學聯培研究生呂姚博士和清華大學博士后、助理研究員黃士飛博士。
Engineering of Cobalt-Free Ni-Rich Cathode Material by Dual-Element Modification to Enable 4.5 V-Class High-Energy-Density Lithium-Ion BatteriesNovember 2022Chemical Engineering JournalDOI: 10.1016/j.cej.2022.140652