Charge-transport kinetics of dissolved redox-active polymers for rational design of flow batteries

Abstract

Charge-transport kinetics of redox-active polymers is essential in designing electrochemical devices. We formulate the homogeneous and heterogeneous charge-transfer processes of the redox-active polymers dissolved in electrolytes. The critical electrochemical parameters, the apparent diffusion coefficient of charge transport (D_app) and standard electrochemical reaction constant (k⁰), are estimated by considering the physical diffusion D_phys of polymer chains (D_app, k⁰ ∝ D_phys). The models are validated with previously reported compounds and newly synthesized hydrophilic macromolecules. Solution-type cells are examined to analyze their primary responses from the electrochemical viewpoints.