Flexible and stretchable thermoelectric devices with Ni-EGaIn liquid metal electrodes for cooling and low-grade-body heat harvesting

Thermoelectric devices based on the Seebeck and Peltier effects enable both converting heat into electricity and energize cooling, presenting a promising potential for personalized thermoregulation. However, when used as a wearable electronic, the flexibility and stretchability of thermoelectric devices with both cooling and heat conversion capabilities rely on solid-state wires connecting p- and n-type materials, which limits the practical application due to the increased resistance and reduced mechanical stability. Here, we propose a stretchable thermoelectric device with liquid metal electrodes that can achieve a temperature reduction of 7.8 K ( ± 0.2) at 5 V and generate 26.2 mV when worn. Owing to the integration of nickel-doped EGaIn liquid metal electrodes and flexible silicone matrix, the stretchable thermoelectric device is still able to maintain excellent cooling even when stretched to strains above 30%, presenting a promising prospect in wearable coolers.