碳酸乙烯酯
电解质
材料科学
阴极
锂(药物)
电导率
离子
溶解
离子电导率
盐(化学)
无机化学
化学工程
化学
电极
有机化学
物理化学
医学
工程类
内分泌学
作者
Bin Liang,Fangyuan Cheng,Xiaoyu Ge,Xuejun Tan,Chun Fang,Jiantao Han
出处
期刊:ACS applied energy materials
[American Chemical Society]
日期:2022-05-03
卷期号:5 (5): 5867-5874
被引量:5
标识
DOI:10.1021/acsaem.2c00205
摘要
The Ni-rich LiNixMnyCozO2 (x + y + z = 1, x > 0.5, Ni-rich NMC) materials are one of the most potential cathodes for high energy density lithium-ion batteries (LIBs) due to their high specific capacity and relatively low cost. However, performances of LIBs with the Ni-rich NCM cathode below 0 °C are restricted by low ion conductivity of the electrolyte and a slow ion diffusion rate at the electrode–electrolyte interphase. Here, γ-butyrolactone (GBL) with a low melting point and high ion conductivity is used to partially replace ethylene carbonate, which is conducive to lower the freezing point and increase the low-temperature ionic conductivity of the electrolyte, and the addition of GBL improves the dissolution of lithium difluoro(oxalato)borate (LiDFOB) in a traditional carbonate solvent. Instead of lithium hexafluorophosphate (LiPF6), LiDFOB can form a F-, B-, and O-rich interfacial phase at the Ni-rich NCM cathode, suppressing the fatal interface reaction and reducing the interface impedance. As a result, the electrolyte using GBL as the cosolvent and LiDFOB as the lithium salt can significantly improve the specific discharge capacity and cycling stability of LiNi0.8Co0.1Mn0.1O2/Li cells at 0 °C and −30 °C. At 0 °C, the LiNi0.8Co0.1Mn0.1O2/Li cells have a discharge specific capacity of 160 mA h g–1 and a capacity retention rate of 99% over 100 cycles. They deliver a decent capacity at −30 °C. This rational design of an electrolyte via optimizing the combination of a solvent and a lithium salt has been confirmed to be a low cost but rather an effective method to improve the low-temperature performances of LIBs.
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