溶剂化
电解质
材料科学
锂(药物)
电化学
阴极
碳酸二甲酯
碳酸丙烯酯
无机化学
氧化物
化学工程
溶剂
物理化学
电极
有机化学
化学
甲醇
冶金
内分泌学
工程类
医学
作者
Zheng Lu,Dong Liu,Kuan Dai,Kailin Liu,Chuyang Jing,Weitao He,Wenran Wang,Chunxiao Zhang,Weifeng Wei
标识
DOI:10.1016/j.ensm.2023.02.029
摘要
High-voltage Li-rich layered oxide materials (LLOs) are considered as the promising next-generation cathode materials because of their high energy density and low cost. However, their electrochemical performance continues to deteriorate under high voltages when using traditional lithium hexafluorophosphate (LiPF6)-based carbonate electrolytes, mostly due to the detrimental reactions with free anions, unstable electrode interface and limited Li+ kinetic process. Here, we demonstrate a highly oxidation-resistant carbonate electrolyte by incorporating multifunctional lithium difluoro(oxalato)borate (LiDFOB) and Tris(trimethylsilyl) Phosphite (TMSPi) additives. It is discovered that the introduction of LiDFOB and TMSPi can manipulate the electrolyte solvation structure by reducing the number of coordinated solvent molecules and free PF6−anions at the electrolyte-electrode interface, thus promoting the desolvation process of Li+, suppressing the generation of harmful HF species and conducive to forming a thin and robust cathode electrolyte interphase (CEI) layer. As a result, the Li||LLO cells with dual additives show excellent cycle stability and improved rate capability in a wide temperature ranged from -20 °C to 55 °C, and the retention rate of LLO||graphite pouch cell (2.5 Ah) using EEDB-TMSPi electrolyte is up to 91.1% after 200 cycles. It is anticipated that the work provides a promising strategy for realizing long-cycle stability of layered cathode materials under high-voltage and wide-temperature conditions.
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