From carbon nanotubes to highly adaptive and flexible high-performance thermoelectric generators

Flexible thermoelectric generators (TEGs) provide a sustainable solution for directly harvesting low-grade heat from various curved surfaces, presenting a promising potential for feeding energy to personal-electronics or internet-of-things systems. Nevertheless, the room-temperature millivolt output of the cutting-edge all-solid-state flexible material-based TEGs (AF-TEGs) is still unappeasable for flexible electronics in practical applications. Here, we report on an AF-TEG consisting of a 3-level structure based on thin-film carbon nanotube (CNT) assemblies that can generate a high voltage (1.05 V) and sufficient outpower (0.95 mW) at moderate ΔT (~44 and 39 K, respectively) for powering an electrochromic device. The advanced nature of the AF-TEG is that conformation is highly adaptive and programmable, showing the surface suitability which can capture waste heat in both in-plane and out-of-plane direction. Moreover, an AF-TEG power management scheme is proposed for powering a commercial LED and an electronic thermometer, which indicate promising potential for practical applications.