New Insights into the Electrochemistry of Carbonyl- and Amino-Containing Polymers for Rechargeable Zinc–Organic Batteries

Organic electrode materials have a large variety of types and could be a replacement for metal compounds in building high-performance rechargeable Zn-ion batteries. Polymers with redox activity can be divided into amino-containing aromatics and quinones, and they show different electrochemical behaviors. Here, we compare two representative polymers, poly(1,5-naphthalenediamine) and poly(1,5-dihydroxynaphthalene), that are electrodeposited onto nanoporous carbon to make cathodes for Zn-ion batteries. Electrochemical energy storage performances of the two polymers are tested at different temperatures ranging from 20 to −20 °C, and the influence of low temperature on their capacity loss, charge transfer resistance, and activation energy is determined. By combining experiment with theory, we unravel key factors of the polymer that favor energy storage performance. The entropy change in the Zn-ion uptake process of an organic electrode material is found to play a key role in the energy storage performance in terms of cycling stability and capacity retention in a cold environment.