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

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 (k(0)), are estimated by considering the physical diffusion D(phys) of polymer chains (D(app), k(0) ∝ 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.