All Sections

The ‘super battery’ that could help electric cars kill the combustion engine

A breakthrough in battery technology could lead to electric cars having five times more range than they do now, making it entirely possible to drive from London to Edinburgh on one charge.

Scientists at the University of Cambridge have been working on a battery technology known as lithium-air, which is said to contain five times more energy than a conventional lithium-ion alternative and a ten times greater potential energy density.

Until now, lithium-air cells have been restricted by the rapid fall-off in performance, but the team of scientists have tweaked the chemistry to counteract this. The result is a battery cell that is said to be 90 per cent efficient.

Professor Clare Grey, a member of the research team, said of the breakthrough: “What we’ve achieved is a significant advance for this technology and suggests whole new areas for research. We haven’t solved all the problems inherent to this chemistry but our results do show routes forward.”

The lithium-air cell usually works by combining lithium with oxygen to form lithium peroxide, which in turn is recharged by applying a current to reverse the reaction. And so energy is created.

Now the challenge is to make the reaction process more reliable and a step towards this has been achieved by converting lithium peroxide to lithium hydroxide (a more easily usable substance) and by making the electrode porous and made from graphene, a recently discovered super-strong form of carbon that happens to be a fantastic conductor of heat and electricity.

A lithium-air battery is said to weigh one-fifth of its lithium-ion cousin and cost one-fifth of the price to make. That means the price of electric cars could be reduced dramatically, seeing as the battery is by far the most expensive component.

It also means the batteries used in an electric car could be smaller, making it easier to house them and without the usual loss of interior or boot space, while a lighter vehicle would offer better performance.

The scientists have so far recharged the battery 2,000 times (a point where capacity usually begins to trail off), with only time the limiting factor in seeing just how reliable their technology is.

However, Professor Grey admits the science is very much “a work in progress” and that once you factor in the necessary packaging needed to house the cell (such as the case) the benefit is reduced, making advances in reducing the weight of these components or finding new materials an important factor.

The scientists believe it could be at least a decade before the improved lithium-air battery makes its way into a production car, which means in the meantime you will have to front-up for a Tesla Model S if you want a range approaching that of your typical petrol and diesel cars.