Improved electrothermal performance of graphene-carbon nanotubes composite films utilizing AgNWs coating method

A safe and high-performance electrothermal heater needs a lower operating voltage to produce heat for a long time and with high efficiency. The graphene-carbon nanotubes composite films and the AgNWs (siliver nanowires) dispersions were prepared and the AgNWs were successfully coated on to the composite films. The electrothermal performance of composite films with different carbon nanotubes (CNTs) contents, polymer additions and coating AgNWs were investigated. The maximum heating temperature decreases when the content of the polymer increases. In addition, the maximum temperature increases with the addition of CNTs. The sheet resistance gradually decreases with improving AgNWs coated amount and the sheet resistance changes little with the bending times on the whole. The microstructure of composite films coated with AgNWs revealed that AgNWs filled the holes on the surface of the composite films. Besides, the electrothermal efficiency, heating rate and cooling rate were significantly improved. For the electrothermal performance of the composite film coated with AgNWs only on the contact surface, the electrothermal efficiency, heating rate and cooling rate were also significantly improved compared with those of the composite films without an AgNWs coating. Therefore, composite film coating with AgNWs is one effective method to significantly improve the electrothermal performance for Gr composite film.