A self-healable, recyclable, and flexible thermoelectric device for wearable energy harvesting and personal thermal management

Flexible thermoelectric devices (f-TEDs) can realize direct energy conversion between heat and electricity, which hold great prospects in wearable power source and personal thermal management. However, conventional f-TEDs made from intrinsically flexible thermoelectric materials have low power density, and elastomer sealed bulk thermoelectric materials-based f-TEDs can hardly achieve active cooling. Additionally, these f-TEDs usually are not self-healable and recyclable, which easily occur fractures in wearable applications. Here, we developed a self-healable and recyclable f-TED by integrating dynamic covalent thermoset polyimine with liquid metal and thermoelectric legs. This f-TED achieves a normalized power density of 1.54 μW·cm−2·K−2, and can deliver a record 13.8 °C on-body cooling effect with a high coefficient of performance (COP) at 3.91 under 7 °C temperature difference, which leads to a low power consumption of ∼ 38 W for the cooling of regular human body. Based on the f-TED, we further developed a personal thermal management system, which can keep body within comfort zone at different surrounding temperatures, also realize healthcare function for fever or sprained ankle. Compared with conventional thermoelectric devices, this f-TED can simultaneously achieve self-healability, recyclability, flexibility, large normalized power density, and high on-body cooling effect with low power consumption. Such f-TED could open up new opportunities to develop devices for wearable energy harvesting and personal thermal management.