通过二进制电解质添加剂在Si@C阳极表面构建一个灵活的,高离子导电的固体电解质介面
Linhu Song1,2, Shiyou Li1,2,3, Jie Wang1,2
1School of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050, P. R. China.
ACS applied materials & interfaces
|October 16, 2023
概括
协同作用的电解质添加剂,乙烯基碳酸盐 (VC) 和二酸 (LiDFP),增强离子电池 (LIB) 中的碳 (Si@C) 阳极稳定性. 这种组合形成了一个灵活的,导电的固体电解质间相 (SEI),提高了循环和速率的性能.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 储能 储能 储能 储能 储能 储能
背景情况:
- 碳 (Si@C) 复合材料是离子电池 (LIB) 的有希望的高容量阳极.
- 循环过程中Si@C的体积膨胀会导致固体电解质间相 (SEI) 不稳定,导致电池性能差.
- 电解质添加剂提供了一种具有成本效益的策略来稳定SEI层.
研究的目的:
- 研究乙烯基碳酸盐 (VC) 和二二酸盐 (LiDFP) 作为Si@C阳极的电解质添加剂的协同作用.
- 改进LIBs中的Si@C阳极的接口特性和电化学稳定性.
- 阐明增强SEI形成和性能背后的机制.
主要方法:
- 半电池中使用VC和LiDFP添加剂对Si@C阳极进行电化学测试.
- 使用光谱技术进行表面表征.
- 使用密度函数理论 (DFT) 的计算分析.
主要成果:
- VC形成一个灵活的SEI,减轻Si粒子碎片化,但增加阻抗.
- LiDFP分解产物 (LiF,Li3PO4) 形成无机SEI层,增强Li+运输并降低界面阻抗.
- 结合的VC + LiDFP添加剂策略创建了一个强大的SEI,具有更好的灵活性和离子导电性.
- 在100个循环后,Si@C/Li半电池的容量保留从68.2%提高到85.1%.
结论:
- 协同的VC和LiDFP添加剂有效地稳定了Si@C阳极中的SEI层.
- 这种方法显著提高了基于Si@C的LIB的循环稳定性和利率能力.
- 该研究提供了一种简单而有效的方法,用于开发高性能Si-based LIBs.
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