电解质
碳酸乙烯酯
脱氢
材料科学
无机化学
氧化物
溶剂
盐(化学)
电化学
化学工程
磷酸三甲酯
环氧乙烷
电极
碳酸二乙酯
碳酸丙烯酯
化学
催化作用
有机化学
磷酸盐
冶金
聚合物
复合材料
物理化学
工程类
共聚物
作者
Ryoichi Tatara,Yang Yu,Pınar Karayaylalı,Averey K. Chan,Yirui Zhang,Roland Jung,Filippo Maglia,Livia Giordano,Yang Shao‐Horn
标识
DOI:10.1021/acsami.9b11942
摘要
The interfacial (electro)chemical reactions between electrode and electrolyte dictate the cycling stability of Li-ion batteries. Previous experimental and computational results have shown that replacing Mn and Co with Ni in layered LiNixMnyCo1–x–yO2 (NMC) positive electrodes promotes the dehydrogenation of carbonate-based electrolytes on the oxide surface, which generates protic species to decompose LiPF6 in the electrolyte. In this study, we utilized this understanding to stabilize LiNi0.8Mn0.1Co0.1O2 (NMC811) by decreasing free-solvent activity in the electrolyte through controlling salt concentration and salt dissociativity. Infrared spectroscopy revealed that highly concentrated electrolytes with low free-solvent activity had no dehydrogenation of ethylene carbonate, which could be attributed to slow kinetics of dissociative adsorption of Li+-coordinated solvents on oxide surfaces. The increased stability of the concentrated electrolyte against solvent dehydrogenation gave rise to high capacity retention of NMC811 with capacities greater than 150 mA h g–1 (77% retention) after 500 cycles without oxide-coating and Ni-concentration gradients or electrolyte additives.
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