Natural rubber-based polymer electrolytes for electrochemical devices: Modification, challenges, advances, and perspectives

The issue of efficient energy storage is now becoming critical and mobilizing researchers and industrial companies worldwide. As energy demands grow, strict strategies will ensure that energy sources are available and accessible at a low cost and with the least possible effect on the environment. Polymer electrolytes (PEs) based on natural rubber (NR) and their derivatives are regarded as eco-friendly and have attracted increasing interest. However, continuous efforts are still being made to improve this type of PEs for energy storage applications. This review addresses the synthesis routes of modified natural rubbers (MNRs), challenges, and typical amendment methods to design flexible structures for electrochemical devices. Furthermore, this review also discusses in depth the evolution of MNR-based PEs from the points of view of adaptable design strategies, fundamental thermomechanical and electrochemical characteristics, and future uses for energy storage. Overall, this review highlights eco-friendly materials like rubber to open doors for novel approaches towards sustainable and renewable energy and boost the economy's value of NR.