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长时间快速充电水性电池的机械理解,使用物理吸附的寡合物作为间相
Arpita Sharma1, Shuo Jin1, Yue Deng2
1Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States.
ACS applied materials & interfaces
|October 31, 2024
概括
在电池电解质中优化聚合物分子重量通过调节沉积和抑制寄生反应来提高电极性能,从而改善电池寿命和效率.
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
- 聚合物科学 聚合物科学
背景情况:
- 聚合物被用作二次电池液体电解质中的添加剂,以提高阳极性能.
- 传统上,聚合物被认为可以抑制导致树突金属沉积的不稳定性.
- 最近的研究表明,聚合物调节电沉积晶体学和形态学,以稳定金属沉积.
研究的目的:
- 研究聚合物类型,分子量 (Mw) 和度如何影响电化学介相形成.
- 了解对Zn电极形态和水性电解质的可逆性的影响.
- 建立用于电池应用的聚合物添加剂选择指南.
主要方法:
- 研究了带有线性聚乙烯糖醇 (PEG) 添加剂的水性Zn-电化学电池.
- 利用光学圆测量和理论计算来分析聚合物涂层厚度.
- 采用电子显微镜和X射线光电子光谱来检查Zn电沉积物.
- 进行了静电循环测量,以评估电池性能.
主要成果:
- 在稀释溶液方案中确定了最佳的PEG分子量 (Mw ≈ 1000 Da).
- 在最佳Mw以上,对Zn电极可逆性和电池寿命的有益影响减少.
- 最佳Mw与和物理吸收PEG电极上的涂层厚度相关.
- 聚合物涂层调节了沉积物形态,并抑制了寄生反应 (例如,ZnO形成).
结论:
- 物理吸收聚合物涂层对于稳定Zn电位和提高电池性能至关重要.
- 控制聚合物Mw和度提供了一种优化电化学介相形成的方法.
- 优化的Zn-I2电池在高电流密度 (50mA/cm2) 中实现了高库伦比效率 (≥99%).
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