Polypyrrole (pPy) electrodes containing polysulfonated aromatic anions are investigated by cyclic voltammetry as electrodes for use in electrochemical supercapacitors. These ‘ladder-doped’ materials are deposited as thick films (ca. 10 μm) having open structures that permit the rapid insertion/ejection (up to 300 mV s−1) of cations and anions from aqueous solution, and give an effective or ‘geometric’ capacitance of up to 0.40 F cm−2. The ‘dual mode’ doping behaviour seems essential for good capacitive response. These electrodes show a remarkable tendency to perform better at high cycling rates, an effect attributed to the way the structure ‘self-organises’ during the self-doping process. Good electrode response depends on protecting the open structure containing hydrophilic ion-conducting channels.
Bibliographical noteWe thank EPSRC and DERA (UK) for financial support, Amanda Pappin (Aberdeen University), Roger Latham (De Montfort University), and Kevin Greene (DERA) for helpful discussions and practical support.
- Dual mode behaviour
- Hydrophilic channels