Ultralight highly porous sponges are attractive for electronic devices due to superelasticity, outstanding resilience, and thermal insulation. However, fabricating an ultralight conductive sponge with low thermal conductivity, mechanical flexibility, and piezoresistivity, as well as adjustable heating behavior, is still a challenge. Here, an ultralight carbon nanofibrous sponge fabricated by pyrolyzing a graphene oxide coated polyimide sponge is reported. The resulting carbon sponge demonstrates a high electrical conductivity of 0.03-4.72 S m-1 and a low thermal conductivity of 0.027-0.038 W m-1 K-1 (20 °C, in ambient air), as well as a low density to ∼6 mg cm-3. Additionally, the sponge exhibits mechanical flexibility, stability, excellent piezoresistivity, and an adjustable heating behavior. Hence, it could be utilized as a sensing device, including thermal management, making them promising for use in smart sportswear, human-machine interfaces, and wearable healthcare devices.
Keywords: graphene oxide; lightweight; nanofibrous sponge; piezoresistive sensor; wearable electronics.