硫减少反应的催化活动与金属中心的Fe原子数量之间的火山相关性
Guolei Cai1, Haifeng Lv2, Guikai Zhang3
1Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Materials for Energy Conversion, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Applied Chemistry, University of Science and Technology of China, Hefei 230026, China.
Journal of the American Chemical Society
|May 2, 2024
概括
研究人员优化了催化剂中的铁原子集群,以提高-硫 (Li-S) 电池中硫还原反应 (SRR) 的缓慢动力学. 具有两个铁原子的特定配置显著提高了电池的性能和循环寿命.
科学领域:
- 电化学
- 材料科学
- 能量储存
背景情况:
- -硫 (Li-S) 电池具有高能量密度,但具有缓慢的硫减少反应 (SRR) 动力学,限制容量和循环寿命.
- 有效的电催化剂对于Li-S电池至关重要,需要在原子利用率和SRR特定场所要求之间保持平衡.
- 了解催化活性位点的原子结构灵敏度是开发实用的Li-S电池的关键.
研究的目的:
- 研究催化活性位点中的铁原子数量对SRR效率的影响.
- 阐明催化剂原子结构与Li-S电池的电化学性能之间的关系.
- 确定用于增强SRR催化的最佳铁原子配置.
主要方法:
- 合成的铁碳催化剂含有不同数量的铁原子 (单原子,二原子,三原子).
- 使用X射线吸收和X射线衍射光谱来研究反应机制.
- 在高硫负载下评估电化学性能,包括面积容量和循环寿命.
主要成果:
- 在SRR催化活性和铁原子数量之间观察到"火山峰"相关性.
- 聚硫化物吸附- 脱附和转化动力学对铁原子数量的增量变化敏感.
- 最好的催化剂具有二原子铁中心,最大限度地提高了原子的效用和中间硫种的转化.
结论:
- 对SRR的最佳催化配置涉及精确的两个铁原子,平衡原子效用和特定场所的需求.
- 这种优化的催化剂设计显著提高了Li-S电池的性能,在高硫负载 (21.8 mg cm-2) 时实现了高面积容量 (23.8 mAh cm-2).
- 这些发现为SRR和其他电催化反应的电催化剂设计提供了关键的见解.
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