Recent research trends in perfluoropolyether for energy device applications: a mini review

Fluorinated polymers are a significant class of functional materials in the field of polymer chemistry. Endowed with remarkable properties, such as high chemical and solvent resistance, enhanced electrical properties, high thermal and electrochemical stability, and low surface energy, they find potential applications in various fields such as chemical processing, electrical/electronic industries, automotive/aircraft industries, medical instrumentations, consumer products, and energy storage or conversion devices. Among a wide variety of commercially significant fluorinated polymers, perfluoropolyether (PFPE) plays a substantial role in energy applications because of its super-hydrophobicity, non-crystallinity, non-flammability, low toxicity, and gas-permeability features. This review briefly confers the properties, production, and significant studies of perfluoropolyether as electrolytes in batteries, followed by a detailed discussion on their role as solid electrolyte interphase (SEI) in metal-ion batteries, oxygen selective membrane (OSM) in metal-air batteries, and as a hydrophobic coating for gas diffusion electrodes in fuel cell applications. Besides, other energy-related applications of PFPE that open up the future scopes of perfluoropolyether in the field of energy storage and conversion devices are also presented.