Lithium-ion batteries could be under threat after the development of polymer materials by the Universities of Surrey and Bristol, along with Superdielectrics Ltd, that could challenge the dominance of these traditional batteries.

Only one year ago, the partners announced scientific results for novel polymer materials that have dielectric properties 1,000 to 10,000 times greater than existing electrolytes (electrical conductors). These stunning scientific findings have now been converted into 'device' scale technical demonstrations.

Researchers from the universities achieved practical capacitance values of up to 4F/cm2 on smooth low-cost metal foil electrodes. Existing supercapacitors on the market typically reach 0.3F/cm2 depending upon complex extended surface electrodes.

More significantly, the researchers managed to achieve results of 11-20F/cm2 when the polymers were used with specially treated stainless-steel electrodes – the details of which are being kept private pending a patent application.

If these values of capacitance can be achieved in production, it could potentially see supercapacitors achieving energy densities of up to 180whr/kg—greater than lithium ion batteries.

Supercapacitors store energy using electrodes and electrolytes and both charge and deliver energy quickly – conventional batteries perform the same task in a much slower, more sustained way. Supercapacitors have the ability to charge and discharge rapidly over very large numbers of cycles. However, because existing supercapacitors have poor energy density per kilogramme (currently around one twentieth of existing battery technology), they have been unable to compete with conventional battery energy storage. Even with this restriction, supercapacitor buses are already being used in China, but the current technology means that they need to stop to be recharged frequently (i.e. at almost every bus-stop).

(ScienceX)