Application of nanocellulose in solar photo/thermal energy conversion and electrochemical energy storage devices

The recent spate of environmental challenges and increase in global warming have spurred increased focus on renewable biomaterials and the development of next-generation green energy conversion and storage devices. Nanocellulose derived from cellulose—the most prevalent biomass resource on Earth, has received wide attention in the world. It is primarily categorized into cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) based on its morphology. Characterized by its high aspect ratio, large specific surface area, unique optical and mechanical properties, and wettability, nanocellulsoe shows high potential for use as a functional material in renewable energy conversion and electric storage applications. This review surveys the latest research on nanocellulose-based membranes, aerogels, and fibers that are used in solar cells, solar evaporators, phase-change material encapsulation, batteries, and supercapacitors. The distinctive structural factors of nanocellulose, such as its morphology, porosity, pore distribution, and crystallinity, significantly affect the efficiency of energy conversion and energy storage capability of related devices. Therefore, the relationship between the structural design of nanocellulose-based materials and performance of target energy devices must be highlighted. This review concludes with a discussion on the current limitations and future prospects of nanocellulose-based energy devices.