High-performance and multifunctional conductive aerogel films for outstanding electromagnetic interference shielding, Joule heating and energy harvesting

High-performance polymer-based functional materials have attracted tremendous interests in various applications. However, it is a challenge to integrate multiple functions without losing the advantages of being light, porous, green and so on. Herein, we designed a conductive aramid nanofiber (ANF)/cellulose nanofibril (CNF)/silver nanowire (AgNW) (ACA) composite aerogel film by directional freeze-drying and moderate compressing. The ACA aerogel film obtained an ideal electromagnetic interference shielding efficiency of 34.34 dB while maintaining a high electrical conductivity of 10.81 S/m. On the other hand, the surface steady-state temperature of the aerogel film reached 111 °C under a low applied voltage of 1.6 V. More importantly, a single-electrode triboelectric nanogenerator (TENG) was assembled by ACA aerogel film and polytetrafluoroethylene (PTFE) film. The open-circuit voltages, short-circuit currents, and maximum instantaneous power density of the TENG exhibited a spectacular value of 104 V, 1.52 μA, and 694 mW/m², respectively, which could light up 23 LED lights at the same time. This novel multifunctional ACA aerogel film holds great application potentials for electromagnetic protection, energy harvesting, and thermal management.