Download PDFThere's a revolution brewing in batteries for electric cars. Japanese car maker Toyota said last year that it aims to release a car in 2027–28 that could travel 1,000 kilometres and recharge in just 10 minutes, using a battery type that swaps liquid components for solids. Chinese manufacturers have announced budget cars for 2024 featuring batteries based not on the lithium that. Download PDFThere's a revolution brewing in batteries for electric cars. Japanese car maker Toyota said last year that it aims to release a car in 2027–28 that could travel 1,000 kilometres and recharge in just 10 minutes, using a battery type that swaps liquid components for solids. Chinese manufacturers have announced budget cars for 2024 featuring batteries based not on the lithium that powers today's best electric vehicles (EVs), but on cheap sodium — one of the most abundant elements in Earth's crust. And a US laboratory has surprised the world with a dream cell that runs in part on air1 and could pack enough energy to power aeroplanes.These and other announcements rely on alternative designs to the conventional lithium-ion batteries that have dominated EVs for decades. Although lithium-ion is hard to beat, researchers think that a range of options will soon fill different niches of the market: some very cheap, others providing much more power. “We're going to see the market diversify,” says Gerbrand Ceder, a materials scientist at the University of California, Berkeley.The pursuit of better car batteries is fierce, in large part because the market is. Batteries are effectively chemical sandwiches, which work by shuttling charged ions from one side (the anode) to the other (the cathode) through some intermediate material (the electrolyte) while electrons flow in an outside circuit. Recharging the battery means shunting the ions back to the anode (see 'How a battery works').Today, most electric cars run on some variant of a lithium-ion battery. Lithium is the third-lightest element in the periodic table and has a reactive outer electron, making its ions great energy carriers. The lithium ions travel between an anode usually made from graphite and a cathode made from a metal oxide, both of which host lithium ions between atomic layers. The electrolyte is typically an organic liquid.Lithium-ion batteries have improved a lot since the first commercial product in 1991: cell energy densities have nearly tripled, while prices have dropped by an order of magnitude3. “Lithium-ion is a formidable competitor,” says Ceder. And with further scope for improvement, some say lithium-ion will be king for a long time. “I think lithium ion will for decades be the technology which powers electric cars, because it's good enough,” says Winfried Wilcke, a recently retired scientist in Los Altos, California, who headed an IBM Research battery projec. The idea of solid-state batteries is to use a ceramic or solid polymer as the electrolyte, which hosts the passage of lithium ions but helps to stem dendrite formation. Not only does this make it easier to use an all-lithium anode — with the attendant energy-density advantage — but getting rid of the flammable organic liquid also means removing a hazard that can cause fires. The cell architecture of solid-state batteries is simpler than that of liquid-based cells, says Nazar. And the solid batteries, in theory, work better both at low temperatures (because there's no liquid to get more viscous when it's cold) and at high temperatures (because the interfaces with the electrodes don't suffer so much when it's hot).Could grinding up lithium batteries help to recycle them?.
