揭示氧电池中的催化电极的形态演变与表面反应之间的相关性
Zhen-Zhen Shen1,2, Yao-Zu Zhang1,2, Chi Zhou1,2
1CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, P. R. China.
Journal of the American Chemical Society
|December 7, 2021
概括
氧电池的阴极会随着时间的推移而降解. 这项研究可视化了纳米粒子变化如何影响电池性能,揭示了控制的金纳米粒子添加增强了稳定性和催化活性.
科学领域:
- 电化学
- 材料科学
- 纳米技术
背景情况:
- 氧电池是一个有前途的储能装置.
- 阴极降解限制了它们的长期运行稳定性.
- 了解纳米级催化剂的形态演变对于提高性能至关重要.
研究的目的:
- 想象 (Pt) 纳米粒子电极在氧 (Li-O2) 电池中的动态演变.
- 在循环过程中将纳米级表面形态变化与催化活性相关联.
- 研究提高催化剂稳定性和性能的策略.
主要方法:
- 使用现场电化学原子力显微镜 (AFM) 来观察在工作中的Li-O2电池中的Pt纳米粒子电极.
- 分析了重复氧化-减氧循环 (ORC) 对纳米粒子形态和 Li-O2 界面反应的影响.
- 研究金 (Au) 纳米粒子修饰对Pt催化剂稳定性的影响.
主要成果:
- ORCs导致了Pt纳米粒子的生长和脱落,改变了Li-O2反应途径,从表面介导到溶液介导,最初增加了放电能力.
- 在250个ORC后,纳米粒子脱离导致核化潜力下降和反应动力减慢,导致性能降低.
- 将适当数量的Au纳米粒子加入到Pt电极上,提高了稳定性并保持了高的催化活性.
结论:
- 在Li-O2电池循环过程中直接可视化了触媒阴极的形态演变和表面反应性之间的相关性.
- 证明纳米粒子脱离是阴极降解的关键因素.
- 展示了Au纳米粒子修饰作为一种有效的策略,以提高基于Pt的Li-O2电池催化剂的稳定性和性能.
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