Comparative Study of Organic Radical Cation Stability and Coulombic Efficiency for Nonaqueous Redox Flow Battery Applications
Comparative Study of Organic Radical Cation Stability and Coulombic Efficiency for Nonaqueous Redox Flow Battery Applications
复制标题
DOI：
10.1021/acs.jpcc.1c00686
复制
发表时间：
2021-06-25
影响因子：
3.7
通讯作者：
Odom, Susan A.
中科院分区：
文献类型：
--
作者：
Attanayake, N. Harsha;Suduwella, T. Malsha;Odom, Susan A.
在构建能量密集型氧化还原液流电池时，液流电池的电池电压至关重要。然而，由于电解质溶液中的自放电或分子降解，氧化还原活性物质的带电形式的稳定性经常在极端氧化还原电势下受到影响，这对实现高电池电压提出了挑战。在这项工作中，我们探索了一系列有机正电解质在非水电解质系统中的化学和循环稳定性，其氧化电位范围为 0.8 V vs Cp2Fe0/+。通过进行本体电解和紫外可见光谱实验，比较了恒电流循环过程中聚合物电解质的库仑效率与其带电形式的化学稳定性之间的关系。一般来说，这些研究表明，具有高氧化电位的有机聚合物电解质在其带电形式下表现出自放电和/或分子降解，从而降低恒电流循环中的库仑效率和/或循环寿命。
When building energy dense redox flow batteries, the cell voltage of the flow cell is critical. However, the stability of the charged forms of redox-active species often suffers at extreme redox potentials due to either self-discharge in electrolyte solutions or molecular degradation, presenting a challenge for achieving high cell voltages. In this work, we explore the chemical and cycling stability of a series of organic posolytes with a 0.8 V vs Cp2Fe0/+ range in oxidation potentials in nonaqueous electrolyte systems. The relationship between the coulombic efficiency of posolytes during galvanostatic cycling and the chemical stability of their charged forms was compared by performing bulk electrolysis and UV-vis spectroscopy experiments. In general, these studies show that organic posolytes with high oxidation potentials exhibit either self-discharge and/or molecular degradation in their charged forms, lowering coulombic efficiency and/or cycle lifetime in galvanostatic cycling.