Surface charge self-recovering electret film for wearable energy conversion in a harsh environment

By virtue of their high conversion efficiency, simple fabrication process and low cost, flexible generators that can convert ambient mechanical energy into electricity are playing a critical role in promoting the development of self-powered wearable electronics. However, urgent challenges have to be overcome to withstand harsh environments, in which the output power performance of all those generators without suitable packaging will deteriorate permanently. Herein, we develop a novel laminated cellular electret film that allows the surface charges to self-recover under ambient air conditions after exposure to an extremely moist atmosphere. The laminated electret cellular film-based flexible generator with sandwich structure can effectively harvest energy from walking motion. Furthermore, this device shows great capability for self-recovery even after operating in extremely moist conditions, an inevitable environment for wearable power supplies. Besides offering valuable new insights, this study opens up new perspectives for low-cost and reliable wearable devices.