A high performance energy storage device using novel patented electrode technology.

There has been significant research investment into alternative methods of energy production that reduce our dependence on fossil fuels. With the exception of nuclear or neo-fossil fuels (e.g. biofuels), these resources (e.g. solar, wind) are neither generated nor converted into useful forms of energy (electric or mechanical) at the 'point of use' or 'on-demand' and require storage and a substantial delivery network. Battery technology will be an intrinsic part of the development of alternative energy strategies. However battery technology, whilst boasting large storage capability, is an essentially electrochemical process, and requires significant charging-up times. Therefore one cannot currently recharge electric car batteries as quickly as filling up a car with petrol. Equally, low capacity and high recharge-times of batteries in mobile devices (lap-tops, mobile phones) limits their ability to contain more functionality. It is obvious that the next breakthrough technology in mobile devices will be in their power packs.

Supercapacitors are strong contenders to provide both high capacity and fast storage/release of energy. Capacitors, as every sixth form science student is aware, can store charge between two electrodes separated by an insulator (the dielectric). The key difference in supercapacitors is that the dielectric is an inherent part of each electrode, and charge is stored within nanoporous pathways within the dielectric. Moving or storing charge without an electrochemical change ( the method of storage in conventional batteries) means supercapacitor charge/discharge rates are fast leading to high power densities. Therefore supercapacitors using dielectrics with large surface area densities (i.e. internal surface per unit volume) from nanoporous materials will have energy densities resembling batteries whilst retaining the fast discharge/charge rates of supercapacitors.

In this proposal, we use a radical new patented technology to generate dielectrics with high surface area densities. This is accomplished by introducing highly interconnected nanoscale pores into the materials in a controlled, reliably repeatable way. Certainly making nanoporous materials is not a new idea in itself. However existing methods are either expensive, or too unreliable. Our patent describes a way to do this, that using cheap materials, fast process-times and good reproducibility. This will be important in taking supercapacitor technology, which has been proved in the laboratory, and making it economically viable as a consumer product.

Through this proposal we will deliver a prototypical supercapacitor device capable in the first instance of powering a lap-top computer, being able to supply power for as long as present lap top devices. Crucially the supercapacitor will also be able to recharge in a matter of minutes making it a far more attractive proposition that present batteries.

At a time when small mobile devices (for entertainment, work and communication) are entrenched in society, the impact of such technology on the efficient working practices of ordinary consumers is self-evident. At a larger but still mobile application level, this technology will energise the development of electrical cars. The batteries in these cars, arriving at 'refill' stations will need to be replenished at similar rates to those currently seen in petrol stations. The eminently feasible way to do this is through the use batteries capable of recharging at fast rates. Convention Li-ion batteries, similar to those found in lap-tops, will not suffice and novel hybrid supercapacitor technology such as our that combine high power with high energy densities will win the day.

A future and more significant implementation of technology, beyond this initial demonstration, will be energy management systems, where energy generated at localized sources by solar, geothermal or windfarms can be stored and distributed on a stabilized energy grid. It is typical of such green energy sources that the power supply, based on an intrinsically variable supply, needs to be attenuated and homogenized. To do so requires back-up stored power supplies capable of delivering energy at high rates; an intrinsic property of supercapacitors.