Polyampholytes in energy storage: A review

Abstract

Polyampholytes contain both positively and negatively charged groups in their structure, which exhibit remarkable electrochemical properties that make them suitable for energy storage applications. Their unique ability to form strong Coulombic interactions with ions and self-associate, especially in aqueous environments, enhances the performance of electrodes and electrolytes. Extensive research on polyzwitterions, a subgroup of polyampholytes, has demonstrated their application in various systems such as batteries, supercapacitors, fuel cells and solar cells. Polyampholytes improve stability, safety, and overall performance in batteries, leading to increased power output. They have been utilized as gel electrolytes in batteries to address the limited cycle life caused by ion stripping/plating. In supercapacitors, polyampholyte hydrogels enhance ionic conductivity and reduce concentration polarization with their multifunctional properties as electrolytes, binders, and separators. In fuel cells, polyampholyte membranes effectively block active components while maintaining high ionic conductivity. Zwitterions show promise as surface coatings in optoelectronic devices like organic light-emitting diodes (OLEDs), perovskite solar cells (PVSCs), and organic solar cells (OSCs) by improving charge transport and enhancing internal electric fields. This review analyzes recent studies on polyampholytes, examining their limitations and future prospects, and inspires new ideas for energy storage applications.