Banik Ananya, Sengupta Uddalak, Hughes Haley, Sabhapathy Palani, Gurkan Burcu, Pentzer Emily B, Powers David C
Texas A&M University, Department of Chemistry, College Station, Texas 77843, United States.
Case Western Reserve University, Department of Chemical and Biomolecular Engineering, Cleveland, Ohio 44106, United States.
ACS Omega. 2025 Jun 12;10(24):26199-26206. doi: 10.1021/acsomega.5c05073. eCollection 2025 Jun 24.
Realization of high-density batteries requires the development of anolytes that display highly negative reduction potentials, solubility, and persistence in the charged state. Azobenzenes have garnered interest as potential anolytes for redox flow batteries. Here, we report the synthesis of a family of substituted azobenzene derivatives and evaluation of their solution-phase electrochemical properties. Systematic synthetic derivatization of this scaffold allows (1) access to anolytes of varying solubility, including intrinsically liquid derivatives that represent potential high-density charge carriers; (2) systematic variation of the reduction potential, and in some cases redox inventory, that provides azobenzenes with highly negative reduction potentials; and (3) control of the lifetime of the azobenzene radical anions that result from one-electron reduction. Electrokinetic experiments demonstrated that fast electron transfer occurs for all derivatives examined. Spectroscopic characterization of monoreduced azobenzene derivatives establishes that decomposition of the azobenzene radical anion proceeds via bimolecular disproportionation. Together, these results provide an experimental basis for the optimization of azobenzene anolytes for electrochemical storage applications, including redox flow batteries.
实现高密度电池需要开发出具有高度负还原电位、溶解性以及在充电状态下具有持久性的阳极电解液。偶氮苯作为氧化还原液流电池潜在的阳极电解液已引起关注。在此，我们报告了一系列取代偶氮苯衍生物的合成及其溶液相电化学性质的评估。对该支架进行系统的合成衍生化能够：（1）获得具有不同溶解度的阳极电解液，包括代表潜在高密度电荷载体的本征液态衍生物；（2）系统地改变还原电位，在某些情况下还能改变氧化还原总量，从而为偶氮苯提供高度负的还原电位；（3）控制单电子还原产生的偶氮苯自由基阴离子的寿命。动电实验表明，所研究的所有衍生物都能发生快速电子转移。单还原偶氮苯衍生物的光谱表征证实，偶氮苯自由基阴离子的分解是通过双分子歧化进行的。这些结果共同为优化用于包括氧化还原液流电池在内的电化学储能应用的偶氮苯阳极电解液提供了实验依据。
