Replacing lithium-ion with treated polymers gives batteries five-fold improvement in storage density

Researchers at the Universities of Surrey and Bristol have used plastics in super-capacitors to build batteries with dielectric properties 10,000 times greater than existing electrical conductors.

Most batteries use the metal lithium-ion as energy storage, but the electronic engineers worked with Superdielectrics, to produce polymer based conductors that might challenge the dominance of conventional batteries.

The team used practical capacitance values of up to four Farads per square centimetre (measure of energy storage) on smooth low-cost metal foil electrodes. Existing super-capacitors on the market typically reach 0.3F/cm2 depending upon complex extended surface electrodes. However, by using polymers with specially treated stainless-steel electrodes, 11-20 Farads per cm2 were achieved.

If the capacitors were built at production level, they could achieve energy densities of up to 180 Watt hours per kilo.

Brendan Howlin, Senior Lecturer in Computational Chemistry at the University of Surrey, said: “These results are extremely exciting and it is hard to believe that we have come so far in such a short time. We could be at the start of a new chapter in the technology of low cost electrical energy storage that could shape the future of industry and society for many years to come.”

Donald Highgate, Director of Research for Superdielectrics, said: “These exciting results are of particular satisfaction to me because they build upon my work in hydrophilic polymers that has been a major part of my professional life; beginning in the later 1970s with extended wear soft contact lenses, and leading in the period 1990 to 2009, to fuel cells and electrolysers of exceptional efficiency.

“The present work, if it can be translated into production, promises to make rapid charging possible for electric vehicles, as well as offering a much-needed low cost method of storing the transient output from renewable energy systems. Wind, wave and solar energy is available but it is intermittent and, without storage, cannot be relied upon to meet our energy needs. This new work would transform the energy system which underpins our entire way of life – it is the necessary development before we and our children can have a genuinely sustainable, environmentally safe energy supply.”