The development of metal oxide based supercapacitors

The development of a viable power storage system for electric vehicles is gaining importance. The cyclic behaviour caused by repeated acceleration and braking requires a robust system for both short and long term energy storage. A system combining a battery and an electrochemical supercapacitor (ES) has been proposed. The battery provides long-term storage and a constant energy output, with the ES assisting during peak load situations. The discovery of electrochemical capacitance in nickel and cobalt oxides has lead to investigation of these materials as alternatives to ruthenium and iridium oxides. Our work with ESS focuses on the recent developments in the cathodic electrolytic deposition of oxide films. Using polyethylenimine we can produce thick, crack-free oxide films after heat treatment. The presence of the polymer also reduces the particle size within the film both as deposited and after heat treatment. Capacitance values of over 100 F/g have been achieved using cyclic voltammetry for both nickel oxide and cobalt oxide.