在氧化流电池中的容量衰变对电解质杂质含量的敏感性
Roman Pichugov1, Pavel Loktionov1, Darya Verakso1
1Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047, Moscow, Russia.
ChemPlusChem
|October 21, 2024
概括
电解质的纯度显著影响氧还原流电池 (VRFB) 的性能. 较低纯度的电解质加快容量色,由于增加了副作用反应,而交叉可以减轻这种色.
科学领域:
- 电化学 电化学 电化学
- 材料科学 材料科学 材料科学
- 储能 储能 储能 储能 储能 储能
背景情况:
- 氧化还原流电池 (VRFB) 由于循环过程中的电解质降解而导致容量减弱.
- 虽然交叉最初被认为是主要原因,但最近的研究强调了来自演化反应 (HER) 的氧化失衡的作用.
- 了解杂质的影响对于改善VRFB寿命至关重要.
研究的目的:
- 调查氧化 (V2O5) 纯度对VRFB电解质降解和性能的影响.
- 量化电解质杂质含量,副作用反应速率和容量衰减之间的关系.
- 评估杂质诱导的副作用和交叉反应之间的相互作用,以确定容量损失.
主要方法:
- 使用V2O5制备三种等级的电解质,其杂质含量不同 (纯度为99.1%至99.9%).
- 使用带有碳感电极的三电极电池进行电化学性质测量.
- 评估VRFB膜电极组件的性能,并监测充放电循环期间平均氧化状态 (AOS) 的增加.
主要成果:
- 电解质的纯度直接影响了副作用的发生率,AOS的增加表明,最低和最高纯度的电解质分别从0.061到0.027天−1不等.
- 增加的AOS与在放电状态下更高的开放电路电压增加相关 (9.6到14.9mV day-1).
- 发现交叉减轻容量衰减,抵消副作用的影响.
结论:
- 氧化的纯度是控制VRFB中电解质降解率和副作用的关键因素.
- 虽然AOS的增加是降解的重要指标,但它不仅仅决定了产能衰减.
- 十字路口通过平衡副作用的影响来减轻容量减弱的作用.
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