Emerging polymer electrodes for aqueous energy storage.

New generation energy storage devices call for electrodes with high capacity, high cycling performance and environmental benignity. Polymer electrode materials (PEMs) are attractive for their abundant structural diversity and tunability as well as engineered conductivity, desirable processability and electrochemical properties for aqueous batteries. We herein overview the state-of-the-art development of PEMs for aqueous batteries, including conventional doped, redox-backbone, redox-pendant and hydrophilic conducting polymers. The merits and demerits of PEMs, and their structural modification and energy storage performance are discussed in detail. To provide a comprehensive understanding of polymer-based aqueous batteries, we correlate the molecular structures of PEMs with their conductivity, morphology and electrochemical behaviors. The review offers an insight into the rational design of conducting polymer electrodes for safe and cost-effective aqueous batteries.