Pei Yi, Chen Qing, Ha Yang, Su Dong, Zhou Hua, Li Shuang, Yao Zhenpeng, Ma Lu, Sanders Kevin J, Sheng Chuanchao, Goward Gillian R, Gu Lin, Yu Aiping, Yang Wanli, Chen Zhongwei
Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, N2 L 3G1, Canada.
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA.
Angew Chem Int Ed Engl. 2022 Nov 21;61(47):e202212471. doi: 10.1002/anie.202212471. Epub 2022 Oct 20.
The key to increasing the energy density of lithium-ion batteries is to incorporate high contents of extractable Li into the cathode. Unfortunately, this triggers formidable challenges including structural instability and irreversible chemistry under operation. Here, we report a new kind of ultra-high Li compound: Li MoO F (1≤x≤3) for cathode with an unprecedented level of electrochemically active Li (>3 Li per formula), delivering a reversible capacity up to 438 mAh g . Unlike other reported Li-rich cathodes, Li MoO F presents distinguished structure stability to immunize against irreversible behaviors. Through spectroscopic and electrochemical techniques, we find an anionic redox-dominated charge compensation with negligible oxygen release and voltage decay. Our theoretical analysis reveals a "reductive effect" of high-level fluorination stabilizes the anionic redox by reducing the oxygen ions in pure-Li conditions, enabling a facile, reversible, and high Li-portion cycling.
提高锂离子电池能量密度的关键在于在阴极中加入高含量的可提取锂。不幸的是，这引发了诸多严峻挑战，包括运行过程中的结构不稳定性和不可逆化学反应。在此，我们报告一种新型的超高锂化合物：用于阴极的LiMoOF（1≤x≤3），其具有前所未有的电化学活性锂水平（每分子式>3个锂），可逆容量高达438 mAh g。与其他报道的富锂阴极不同，LiMoOF具有卓越的结构稳定性，可抵御不可逆行为。通过光谱和电化学技术，我们发现以阴离子氧化还原为主导的电荷补偿，氧释放和电压衰减可忽略不计。我们的理论分析表明，高水平氟化的“还原效应”通过在纯锂条件下还原氧离子来稳定阴离子氧化还原，从而实现简便、可逆且高锂含量的循环。
