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2017-11-17

Will solid-state batteries power us all?




Electric cars powered by solid-state batteries could be on the road by 2020—but existing batteries are improving all the time

BATTERIES have steadily been getting better, but progress is slow. Rechargeable lithium-ion batteries still provide the best combination of compactness, power and efficiency for products ranging from drones to smartphones and cars. Research groups around the world are searching for more powerful batteries but none, as yet, has ventured much beyond the laboratory. Sir James Dyson (pictured), a British inventor who makes vacuum cleaners, hand-dryers and other electrical goods, says he is investing £2bn ($2.7bn) to develop an electric car which will be powered by a novel “solid-state” battery. Is this the breakthrough the world has been waiting for?
It is hard for scientists to find a material better than lithium from which to make a battery for use in portable devices and transport. Lithium is a light, highly conductive metal, but inherently unstable, so it is used instead in a safer form as a compound containing lithium ions (electrically charged particles). Lithium-ion batteries are typically made as laminated structures with a material called an electrolyte at their centre. This is a liquid or gel-like substance through which the lithium ions shuttle back and forth between electrodes when the battery is charged or discharged. Manufacturing faults, damage and general wear can lead to a short circuit through the electrolyte, causing the battery to overheat or even burst into flame. A solid-state lithium-ion battery would have a solid electrolyte and would be safer and possibly more powerful.
Such batteries already exist, but are usually small coin-sized cells that provide backup power in electrical circuits, such as computers. A number of groups are looking at ways to scale up the production of such cells so they can be made into batteries that are sufficiently big and powerful to drive an electric car. One company working in this area, an American startup called Sakti3, was bought by Dyson for some $90m in October 2015. Sakti3, based in Michigan, is secretive, but it is known to have been making experimental solid-state lithium batteries using a thin-film deposition process, a method widely used to produce things like solar panels and display screens. The aim is to produce low-cost batteries with a long and safe service life, and the energy density to greatly increase the range of a typical electric car—perhaps even to double it.
Dyson says its electric car and new battery should be ready for the road in 2020. Toyota has a similar time-frame in mind for the launch of a new electric car that will be powered by a solid-state lithium battery that it is developing. Having commercially viable production techniques will be the key. Existing lithium-ion batteries, like those being made in Elon Musk’s new $5bn “Gigafactory” in Nevada for his Tesla electric cars, will continue making progress and falling in cost, if only incrementally. This means the solid-state lithium battery has to overtake its more established rival by some margin, not only in terms of cost but also performance and reliability. If the new battery can do that, it would be a real breakthrough