Scalable-produced 3D elastic thermoelectric network for body heat harvesting.

Flexible thermoelectric generators can power wearable electronics by harvesting body heat. However, existing thermoelectric materials rarely realize high flexibility and output properties simultaneously. Here we present a facile, cost-effective, and scalable two-step impregnation method for fabricating a three-dimensional thermoelectric network with excellent elasticity and superior thermoelectric performance. The reticular construction endows this material with ultra-light weight (0.28 g cm -3 ), ultra-low thermal conductivity (0.04 W m -1  K -1 ), moderate softness (0.03 MPa), and high elongation (>100%). The obtained network-based flexible thermoelectric generator achieves a pretty high output power of 4 μW cm -2 , even comparable to state-of-the-art bulk-based flexible thermoelectric generators.