在电解质/电极界面反应的实体动力学分析 - - 总频率生成振动光谱研究
Yonatan Horowitz1,2, Hui-Ling Han1, Philip N Ross1
1Materials Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
Journal of the American Chemical Society
|December 15, 2015
概括
固体电解质介面 (SEI) 对于电池的寿命至关重要. 研究人员确定了由阳极上的二甲基碳酸盐分解形成的Si-ethoxy中间体,揭示了SEI形成机制的关键见解.
科学领域:
- 电化学
- 材料科学
- 表面化学
背景情况:
- 长期的电池性能依赖于固体电解质介面 (SEI),这是防止电解质降解的保护层.
- 了解阳极上的SEI形成对于开发先进的离子电池至关重要.
研究的目的:
- 在晶体电极上研究形成SEI的还原产品.
- 阐明二甲基碳酸盐 (DEC) 分解在SEI形成中的作用.
- 确定表面终端如何影响SEI的组成.
主要方法:
- 使用现场总频率生成振动光谱 (SFG-VS) 进行接口敏感分析.
- 在半电池系统中研究了1.0M的LiPF6/乙烯碳酸盐 (EC) /二乙烯碳酸盐 (DEC) 电解质.
- 在各种应用电位下,对终端Si100) 晶片进行了研究.
主要成果:
- 鉴定出一种由DEC分解产生的Si-ethoxy (Si-OC2H5) 表面中间体.
- 证明SEI表面的组成取决于表面的末端 (酸度).
- 在SEI的运行条件下提供特定化学物种的直接证据.
结论:
- 在电化学电解质降解机制中,将DEC降解为乙氧基是关键步骤.
- 阳极上的SEI形成受表面化学和电解质分解途径的影响.
- 这些发现为电池中SEI形成的一般机制提供了新的视角.
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