Recent advances in flexible supercapacitors based on carbon nanotubes and graphene

Owing to the rapidly growing market for flexible electronics, there is an urgent demand to develop flexible energy storage devices. Flexible supercapacitors have received much attention due to their good flexibility, fast charge/discharge rate and long lifecycle times. Carbon nanotubes (CNTs) and graphene have good mechanical properties, which make them suitable for flexible supercapacitors. Based on different nanostructures of CNTs and graphene, we summarized the recent progress in CNTs- and graphene-based flexible supercapacitors with a brief description of the basic principles for evaluating their performance. Special emphasis was given to fabrication methods, capacitive performance and electrode configurations of different flexible supercapacitors. Furthermore, the remaining challenges and future research directions for CNTs- and graphene-based flexible supercapacitors have also been discussed.