Polymer-Inspired and Polymeric Deep Eutectic Solvents for Energy Storage: A Review and Outlook

The current challenge of storing energy has become more critical than ever, particularly with the emergence of intermittent renewable energy resources. Deep eutectic solvents (DESs) have become promising multitasking agents for a wide spectrum of energy-related applications. Among these, energy storage is currently regarded as a simultaneously challenging and yet a promising research area, aiming to maximize energy harvesting from renewable sources. Polymer-inspired DESs (PIDESs) and polymeric-based DESs (PDESs) represent novel opportunities for electrochemical energy storage and conversion (EESC) technologies, as their fundamental functionalities offer an intriguing pathway for developing next-generation EESC systems with high performance, a wide electrochemical window, and extended lifespan. This review sheds light on the recent applications of PIDESs and PDESs in EESC devices, including fuel cells, Li-, Al-, Zn-, Na-, and Mg-based batteries, and supercapacitors. It additionally identifies current gaps and how exploiting these neoteric agents can maximize device efficiency and facilitate controlled design. Finally, this review outlines the future potential of PIDESs and PDESs and their significance in this rapidly evolving field. To the best of our knowledge, this is the first review that encompasses the roles of PIDESs and PDESs in energy storage systems.