Current affairs

A new generation of powerful viral batteries could mean a breakthrough for electric cars
June 3, 2009

Whether it's a mobile petering out mid-call or a laptop with "lazy battery syndrome" holding ever smaller amounts of charge, most gadget owners know the problem of dying batteries. For most of us this powerlessness is a minor inconvenience, but for hi-tech manufacturers and scientists it is one of the biggest blocks to building a new generation of electronic devices.

Scientists and entrepreneurs are dreaming up plans for new electronic car batteries that can charge faster and longer to help reduce the 20 per cent global greenhouse gas emissions generated by transport. Indeed for many green technology enthusiasts there is no task more vital than rebooting the humble car battery. Build a battery that can power a car for 300 miles and you are halfway to a world without oil. Build one that charges in the time it takes to fill a tank of petrol and you have the makings of a commercial hit too.

A battery is just a container of chemicals designed to produce electrons. They have two ends: one positive, one negative. The electrons move from the negative terminal (the cathode), via an electrically conducting material (an electrolyte) to the positive terminal (the anode), making the electrical current. It's this flow that runs out quickly in cheap batteries, and is also unstable at high temperatures—lithium ion batteries often explode when they get too hot. The other obstacle is charging time. Today's typical electric car battery copes (just about) with the overnight charge needed for a short 30-mile journey. But cross-country drivers might well balk at the need to plug in at a service station for three to eight hours at a time. Even the Tesla Roadster, the world's first electric sports car—which goes from 0 to 60mph in 3.9 seconds and costs £92,000—takes up to three and a half hours to top up. Detaching ions off the cathode and towards the anode is, at present, a painfully slow process.

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Roll in the nanoballs. In March 2009, Professor Gerbrand Ceder, of the Massachusetts Institute of Technology (MIT), unveiled a battery capable of charging a hundred times faster than ordinary batteries. Their cathode comes with tiny balls of lithium iron phosphate, called nanoballs because each measures just 50 nanometres (one billionth of a metre) across. The nanoballs release the lithium-ions much more rapidly, making the charge much faster. This means, potentially, that a plug-in hybrid car could charge in five minutes, and a mobile phone in ten seconds.

In addition to providing a partial solution to climate change, this new technology is going to make someone a tidy profit—even if only a fraction of the world's 806m cars and light trucks switch to batteries instead of burning 260bn gallons of fuel. Take the new Chevy Volt—the car that American giant GM hopes can catapult it from economic misery into the hearts of green-minded and cash-conscious drivers. The Volt is targeted primarily at commuters driving less than 40 miles a day, which it can do without petrol or carbon emissions. For longer trips it can also run on petrol, ethanol, bio-diesel or even hydrogen until the battery is recharged. It won't launch in the US until 2010, but fans have already launched an online "want list"—with 48,000 people from 88 countries signing up.

Other entrepreneurs are getting in on the act. A company called A123 Systems has recently created a lithium-ion battery that is only slightly larger than an AA battery but 800 times more powerful. In April it announced a link-up with Chrysler for its battery-powered cars due to launch in 2010, and is also producing batteries for the Shanghai Automotive Industry Corporation, China's first hybrid manufacturer.

Lithium-ions are just the beginning. EEStor, a secretive Texan company, builds ultracapacitors: larger devices capable of storing electricity by separating the chemical charges in a normal battery. They use aluminium-coated barium titanate powder, and EEStor claims that they supply around ten times the energy density of a normal car lead battery at a fraction of the weight and size. Until recently these claims had been dismissed as a weird green scam, but news of a tie-up with a Canadian-based company, Zenn Motor Company Systems, has convinced some doubters. The next step will be to make a prototype for a motorway-speed, long-range electric car with an ultracapacitor—which Zenn's CEO says will probably happen in 2010.

Potentially the most interesting battery, however, is being developed at MIT, down the corridor from Gerbrand Ceder's nanoballs, in the office of Angela Belcher. Belcher is a materials chemist and something of a rock star in the field of batteries. I spoke to her at the Aspen Institute's environmental forum in March, where she had just revealed a potentially even more radical invention: a viral battery. Her MIT team has made a lithium-ion battery with genetically-engineered viruses playing the role of anode and cathode. The virus coats itself with cobalt oxide and gold to provide the charge. The viral battery has the same capacity and performance as the rechargeable one that runs the Chevy Volt, but is much smaller. Indeed Belcher believes that it can be scaled to almost any size and even moulded to the shape of its container, be it a car or mobile phone. And no need to worry about infection either; the virus, she told me, is a common bacteriophage: infectious for bacteria but harmless to humans.

It may be five or ten years before the viral batteries and nanoballs being dreamed up at MIT become commercially viable. Much depends on the market for electric cars and, in turn, the price of oil. But Washington's new commitment to tackling climate change will make the most difference: in March President Obama toured a factory making electric cars and pledged $2.4bn of his stimulus fund towards their development. He has also mooted a $7,000 tax credit for the purchase of alternative vehicles, and in May he announced tough new rules for automobile emissions, imposing the first US limits on climate-altering gases from cars and trucks. The rules come into effect in 2012, with the goal of making the US 40 per cent cleaner and more fuel-efficient by 2016 and, ultimately, cutting greenhouse gas emissions by 80 per cent by 2050. All of this will nudge exploratory technologies in university labs towards the market. Indeed, if the administration continues to pressure GM on electric cars (as it is in a strong position to do given the aid it is handing them) consumers might see the tiger in their tank replaced by a virus sooner than they think.