Wearable fiber-shaped energy conversion and storage devices based on aligned carbon nanotubes

With the rapid development of wearable electronics, it is urgent to develop flexible, lightweight and high-performance wearable energy conversion and storage devices (typically in a fiber-shaped format) to be used as power supplies. Due to their unique structure, fiber-shaped energy devices that can be easily woven or integrated into clothes, bags and other textiles have been widely investigated in the last ten years. In fiber-shaped energy devices, fiber electrodes have a significantly effect on the performance of the resultant devices. Compared with conventional fiber electrodes, such as metal wire and conducting material coated plastic fibers, aligned carbon nanotube (CNTs) fibers or aligned CNT film wrapped plastic fibers showed higher flexibility and stability, which have been widely used as highly efficient electrodes in fiber-shaped energy devices. So far, various fiber-shaped energy conversion devices (such as solar cells and light emitting diodes) and energy storage devices (e.g., supercapacitors and batteries) have been developed, and great achievements have been received. In this review, we will summarize recent advances on the aligned CNTs-based fiber-shaped energy devices ranging from energy conversion to storage and self-powering devices, following by discussing their opportunities and challenges for practical applications in the future. (C) 2016 Elsevier Ltd. All rights reserved.