Lab breakthrough could vastly improve electric car batteries

Electric car batteries could be charged significantly quicker and last much longer after a new laboratory discovery in the UK.

Researchers at Bristol and Surrey universities are attempting to develop new supercapacitors, which are quickly chargeable energy storage devices that offload power at a rapid pace, using new materials with the aim of rivaling, or even surpassing, lithium-ion batteries currently used in phones and electric cars.

One of the new materials tested is a transparent, flexible polymer originally developed for soft contact lenses in the 1970s by Donald Highgate, now research chief at Superdielectrics, and since found to be surprisingly capable at holding an electrostatic field.

Highgate, a former director at ITM Power and now working at Superdielectrics in conjunction with Bristol and Surrey, said: “It could have a seismic effect on energy, but it’s not a done deal.”

Highgate and the universities now need to replicate the prototype's performance on a larger scale.

Supercapacitors are used for harvesting energy from braking in electric vehicles, and have been deployed in cars made by companies such as PSA Peugeot Citroen since 2010.

Gareth Hinds, Fellow of the UK’s National Physical Laboratory, told the BBC: “The two main advantages of conventional supercapacitors over batteries are their ability to handle much higher charge and discharge rates, and their longer cycle life. The downside is that they tend to be relatively high cost and can only store a few seconds-, or at most, minutes-worth of power.”

Currently, the best supercapacitors hold just 5% of the energy per kilogram of a lithium-ion battery. This would make Highgate’s newly tested polymer’s ability to hold an electrostatic field all the more important for the technology’s future development.

Ulrik Grape, chief executive of supercapacitor manufacturer NaWa technologies, said: “Supercapacitors don't store as much energy but their response is instantaneous. So a supercapacitor could handle acceleration and energy recovery under braking - taking care of the stressful part of a battery's life - possibly doubling or tripling a battery's life expectancy.”

Increasing the life expectancy of energy storage devices is seen as critical to the future success of renewable energy.