Natural Biopolymer Materials for Flexible Energy Conversion and Storage Devices

Abstract

Natural biopolymers have attracted extensive research interest in the past decades for application in flexible energy conversion and storage devices, which has been largely motivated by the rapid development of Internet-of-Things (IoT) devices and the increasing demand for portable power sources to enable autonomous functionality. Various natural biopolymers, such as cellulose, chitin/chitosan, starch, silk, gelatin, agarose, and lignin, have been explored to date. Natural biopolymers have several prominent advantages over synthetic polymers, including low cost, high abundancy, excellent recyclability, mechanical flexibility, biodegradability and biocompatibility. Natural biopolymers, being used alone or in combination with synthetic polymers, have attracted increasing research attention for various functional components in flexible energy devices, including lightweight and flexible substrates, electrode materials, templates for designing hierarchical structures, and host polymers/gelling agents for electrolytes. In particular, natural biopolymers have been demonstrated as promising candidates for high-performance gel electrolytes with decent ionic conductivity, high flexibility, and electrochemical stability. This chapter presents the progress in natural biopolymer-based flexible energy conversion and storage devices, such as solar cells, thermoelectric devices, supercapacitors, and batteries. The key challenges and future perspectives are also discussed by the end of the chapter to shed light on the future research and development.