A new concept of hybrid supercapacitors has been designed with a conductive polymer as the positive electrode and activated carbon as the negative electrode. The chosen polymer was poly(4-fluorophenyl-3-thiophene) or P-4-FPT, whose good doping properties are well known. Several activated carbons were tested, and the results reported here were obtained with carbons from Spectracorp (BP25 and YP17). The mass ratio of active materials was calculated to obtain the maximum cell voltage (3 V). The system studied in our laboratory was 4 cm(2) test cells which reached 48 Wh/kg of maximum energy associated with 9 kW/kg of maximum power (considering the mass of the active materials). Industrial prismatic prototypes were then assembled, containing 60 cm(2) electrodes. These prototypes reached a maximum energy of 7.5 Wh/kg (total mass), and a maximum power of 250 W/kg. (C) 2001 The Electrochemical Society.