Alexis Laforgue

Polythiophene-based supercapacitors

Abstract Polythiophene (Pth) and polyparafluorophenylthiophene (PFPT) have been chemically synthesized for use as active materials in supercapacitor electrodes. Electrochemical characterization has been performed by cyclic voltammetry and an electrode study has been achieved to get the maximum capacity out of the polymers and give good cyclability. Specific capacity values of 7 mAh g −1 and 40 mAh g −1 were obtained for PFPT and polythiophene, respectively. Supercapacitors have been built to characterize this type of system. Energy storage levels of 260 F g −1 were obtained with Pth and 110 F g −1 with PFPT.

Activated Carbon/Conducting Polymer Hybrid Supercapacitors

This paper presents the work carried out within a European Union (EU) project which led to the development of 3 V and 1.5 kF preseries supercapacitor modules and 2 kW stacks based on hybrid cells with poly(3-methylthiophene) as positive electrode and activated carbon as the negative electrode with propylene carhonate-tetraethylammonium tetrafluoroborate electrolyte. These prototypes, which display a concept of hybrid cell operating with a high-surface-area activated carbon and a conventional electronically conducting polymer, both commercially available, and with a nontoxic and nonvolatile electrolyte, provide a successful response to the market demand for high power and energy supercapacitors operating with an environmentally friendly electrolyte.

Hybrid Supercapacitors Based on Activated Carbons and Conducting Polymers

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.

A Nonaqueous Asymmetric Hybrid Li4Ti5 O 12 / Poly(fluorophenylthiophene) Energy Storage Device

An asymmetric hybrid energy storage device has been built using a lithium titanate intercalation anode and the pseudocapacitive electronically conducting polymer poly(fluorophenythiophene). Results show that the device operates in the power range of electrochemical double-layer capacitors, while having three to four times their energy density, and a voltage profile and self-discharge characteristics typical of a battery. The cycle life is also intermediate between that of a battery and a supercapacitor, in the range of several thousands of cycles.

Chemical synthesis and characterization of fluorinated polyphenylthiophenes: application to energy storage

Some fluorinated polyphenylthiophene have been chemically synthesized with good yields. The characterization of their positive and negative doping processes was performed by cyclic voltammetry and showed high capacities, but proved no real stability in cycling experiments. The application of the P-4-FPT as electroactive material in supercapacitor systems showed interesting properties in term of energy and power delivered.