Conducting polymers with redox active pendant groups: their application progress as organic electrode materials for rechargeable batteries

Conducting redox polymers (CRPs) composed of a conducting polymer backbone and covalently linked redox active pendant groups have attracted increasing interest as electrode materials for rechargeable metal batteries. Combining the intrinsic properties of conducting polymers and redox active polymers, CRPs would possibly bring high charge capacity, fast charge transport, and stable cycling provided that the individual merits of the backbone and the redox active groups can be preserved and act in a synergistic manner. Thus, the application of CRPs requires good matching of the redox chemistry of the pendant group and the CP backbone. In this review, the fundamentals of CRPs are first introduced. Second, the application advances of CRPs as active electrode materials in monovalent metal-ion/sulfur (e.g. Li-ion/S, Na-ion/S) batteries and multivalent-ion/S (e.g. Zn-ion/S) batteries are summarized based on their specific redox reactions. Perspectives on pressing challenges and further research opportunities regarding CRP-based electrode materials are also discussed. This review provides concepts of rational design of CRPs to develop highly efficient organic electrodes and promote their practical applications.