Wearable thermoelectric cooler encapsulated with low thermal conductivity filler and honeycomb structure for high cooling effect

Thermoelectric coolers (TEC) based on Peltier effect has been widely used in small scale cold storage because of its zero emission, and high efficiency, while wearable thermoelectric coolers (WTEC) for personal temperature management is garnered tremendous scientific attention. For out-of-plane structured WTEC using inorganic TE materials encapsuled in flexibility substrate, on the one hand, encapsulating materials are required to have low thermal conductivity, high reliability and high flexibility, and on the other hand, heat dissipation of devices is required to be lightweight, portable and efficient. For this reason, we propose a composite material synthesised from SiO₂ aerogel, hollow glass beads (HGB) and polydimethylsiloxane (PDMS) as a filler, which takes advantage of the low thermal conductivity of (0.094 W/mK) to increase the temperature difference in the encapsulation layer of the device, and moreover performs the fabrication of honeycomb holes, which further reduces the thermal conductivity of the encapsulation layer and at the same time brings a certain degree of compression resistance to the device. Radiative cooling (RC) films synthesised using hexagonal boron nitride (HBN) and PDMS for lowering the temperature of the hot side in outdoor environments without additional energy consumption, providing heat dissipation at the hot side. Honeycomb wearable thermoelectric cooler (HWTEC) proposed in this work deliver high cooling temperature difference of 9.1 °C and 6.5 °C indoor and outdoor through human wear. Our work represents an important step in the development of flexible TE devices and is believed to have promising future applications in personal thermal management, e-skin and smart textiles.