陷入的O2和电压的起源在多层的丰富的阴极中消失
John-Joseph Marie1,2, Robert A House3,4, Gregory J Rees1,2
1Department of Materials, University of Oxford, Oxford, UK.
Nature materials
|March 1, 2024
概括
氧氧还原阴极中的电压衰减是由不可逆转的氧氧还原反应和氧气损失引起的. 越来越多的空隙捕获氧气,导致颗粒裂变,并降低了丰富材料中的电化学活性.
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
- 储能 储能 储能 储能 储能 储能
背景情况:
- 与传统的过渡金属阴极相比,氧氧还氧阴极提供更高的能量密度.
- 电压衰减,即循环期间放电电压的下降,是这些材料面临的重大挑战.
- 最初的研究表明,可逆的氧氧还氧反应涉及纳米空隙中被困的氧分子.
研究的目的:
- 为了阐明氧氧回氧阴极中电压衰减背后的机制.
- 调查氧 (O) 氧化解氧可逆性和氧气损失在容量衰减中的作用.
- 为了确定过渡金属迁移和空隙形成的根本原因.
主要方法:
- 在延长循环期间对氧氧还氧化能力损失的分析.
- 空洞进化和氧 (O) 分子在阴极结构中被困的特征.
- 对粒子完整性和表面形态变化的研究.
主要成果:
- 电压衰减归因于O2-O2氧化还原过程和氧气损失的可逆性降低.
- 封闭的纳米大小的空洞捕获氧气在循环过程中生长,增加电化学不活性氧气.
- 颗粒裂变和表面的空隙导致氧气释放,加剧了色.
结论:
- 氧气形成的热力学驱动力是电压衰减的主要原因.
- 这种驱动力诱导过渡金属迁移和空隙形成,导致产能丧失.
- 了解空洞演化和氧气管理对于开发稳定的氧氧氧化回氧阴极至关重要.
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