This contribution deals with the fabrication of a new generation of supercapacitors for harsh environment (avionics) based on nanostructures layers fabricated by spray-gun deposition method. Thanks to the fabrication of electrodes using spray-gun and the utilization of specific ionic liquids developed at Thales, we were able to achieve a capacitance of 20F/g (for a whole cell) and a power of 40kW/kg using carbon nanofibres (CNFs) mixed with reduced graphene oxide (RGO). These results are not the higher values obtained in literature but they are extremely interesting considering that the final device needs to stand temperature between -55°C and +105°C for avionics applications and that no commercial supercaps in the world are able to work in this interval. Only using these ionic liquids and the specific electrodes, it is possible. These supercapacitors were fabricated using spray-gun deposition method which is an extremely interesting technique from an industrial point of view considering that it can be easily implemented in roll-to-roll fabrication.