Limited range is one of the most frequent criticisms of EVs. Although a 300-mile rating is becoming increasingly common for current electric cars, some fossil fuel models can go twice as far on a tank. But what if your BEV could do 900 miles on a single charge? German battery startup Theion is promising technology that could deliver this possibility as soon as 2024.

The key to Theion’s technology is sulfur, and in fact the company’s name is derived from the Greek for this yellow mineral. According to CEO Dr Ulrich Ehmes, it has the properties required to deliver a revolution in battery chemistry, with knock-on benefits in all the key areas for EVs. Co-founder and CTO Marek Slavik had been working on the technology for the best part of a decade, and Ehmes has recently arrived to make it a production reality.

As many EV haters on social media will tell you, EV batteries are full of rare earth minerals, which makes them expensive and ethically problematic to manufacture, particularly when sourcing cobalt from the Congo. Theion’s strategy is to base its battery technology on minerals that are far more abundant than those used in current Lithium-Ion cells, but that have similar potential for energy density.

Sulfur is the tenth most abundant element on Earth, and local sources are usually available in any chosen location in the world. “Existing battery technology uses nickel, manganese, and cobalt for the cathode,” says Ehmes. “It’s called NMC 811, because it has 80% nickel, 10% cobalt, 10% manganese. In our case, we replace this NMC 811 with sulfur. So we have no nickel, no manganese, no cobalt, and we replace the current collective folds of copper and aluminum withy graphene so we have also no aluminum and no copper in our cells either. The only things we have in our cells are lithium metal foil, sulfur, and carbon.” To make this technology work, the sulfur must be melted to form crystals, but this is only 112C (235F).

So what are the advantages of Theion’s radical shift in battery chemistry? Of course, you could make an EV go 900 miles with current battery technology. The problem would be how heavy that battery would be, and how much space they require. Current EVs do somewhere between 3 and 5 miles per kWh, although power consumption can be a lot more if you drive in a “spirited” fashion or in extreme temperatures. Let’s say 4 miles per kWh to be fair. Using this figure, you would need 225kWh to go 900 miles. Current Tesla Model 3 “2170” batteries have a density of 260Wh/kg, although the latest technology can hit 350Wh/kg. Assuming the latter, a 225kWh battery would weight 643kg, but with Tesla 2170 cells it would be 865kg. With a Tesla Model 3 Long Range weighing around 1,850kg, you can see why no current EVs are offering a 900-mile range.

Battery weight is derived from the “gravimetric density” the cells, but the other consideration is “volumetric density” – how much space the batteries take up. Tesla Model 3 2170 batteries reportedly have a volumetric density of 416kWh/liter. While weight is important, you also need to fit your batteries into a reasonable amount of space, so there is plenty left for passengers and cargo. Most current designs put the batteries in a “skateboard” design under the floor to maximize this space, but you still see a lot of EVs sitting higher than internal combustion equivalents to provide the necessary floor thickness.