Present and future thermoelectric materials toward wearable energy harvesting

Thermoelectric (TE) devices emerge as an important renewable energy source with great potential to take advancement of the widely-abundant and normally-wasted thermal energy, which are expected to provide sufficient energy for long-term operations, avoiding the inconvenient battery replacement or frequent recharging. Recently, the wearable energy conversion devices to provide electricity for portable electronics have attracted increasing attention with the available of novel low-power portable equipment. This paper reviews recent developments of TE materials toward flexible or wearable energy harvesting based on film- and fiber-based materials. The potential of film- and fiber-based TE materials have been discussed for the next generation of sustainable energy supply toward wearable energy harvesting owing to their low-weight, high flexibility, and reliability. Remaining challenges and perspectives of flexible devices are also examined to suggest for practical application toward wearable energy harvesting. (C) 2019 Elsevier Ltd. All rights reserved.