通过弱联体场对催化中心的高旋转状态调节,以促进-硫电池中硫逆氧反应
Qing Li1,2, Zhipeng Ma1,3, Ming Liu1
1Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, 066004, China.
Angewandte Chemie (International ed. in English)
|November 7, 2024
概括
研究人员控制了化 (CoF2) 的旋转状态,以增强硫电池 (LSB). 这种旋转控制加速了硫氧化还原反应,提高了电池容量和循环寿命.
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
- 固态化学 固态化学
背景情况:
- 过渡金属化合物的旋转状态极大地影响硫电池 (LSB) 的电子特性和反应动力学.
- 对旋转状态的精确控制对于理解结构-性能关系和为LSB开发先进的电催化剂至关重要.
- 在电催化剂中设计和可预测地定制自旋状态仍然是一个重大挑战.
研究的目的:
- 以可预测的方式调整CoF2的旋转状态,以提高硫电池的性能.
- 研究旋转状态操纵影响硫氧化还原反应 (SRR) 的机制.
- 展示旋转控制的应用,作为加速SRR和提高LSB性能的一种策略.
主要方法:
- 密度函数理论 (DFT) 计算以建模电子结构和相互作用.
- 量身定制的CoF2电催化剂的实验合成和表征.
- 使用改性电催化剂的LSB的电化学测试,包括循环性能和速率能力测量.
主要成果:
- 在高旋转状态 (3d7,t2g5eg2) 中,通过的弱协调场效应成功合成了CoF2,特别是Co2+ .
- 实验和计算数据证实SRR期间从低旋转到高旋转状态的过渡,通过Co-S和Li-F债券产生强烈的相互作用.
- 削弱的S-S键和促进的Li2S2/Li2S核化导致了高容量 (447.7 mAh g-1在10 C) 和稳定的循环 (1000 个循环).
- 在高硫负载10毫克厘米-2.2时,实现了585mAhg-1的实用容量.
结论:
- 通过的场效应证明了对CO2+d电子自旋状态的理性控制.
- 旋转状态操纵有效地加速了LSB中的硫氧化还原反应.
- 这种方法为设计高性能电催化剂提供了一个新的途径,通过利用用于储能应用的旋转状态控制来实现这一目标.
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