MIT reckons it’s overcome one of the biggest barriers to the acceptance of electric cars – the time it takes recharging them – while at the same time halving the cost of batteries.
Its new battery relies on what’s called a semi-solid flow cell, in which solid particles are suspended in a carrier liquid and pumped through the system. The battery’s cathodes and anodes are composed of particles suspended in liquid electrolytes, which are pumped through systems separated by a filter, such as a thin porous membrane.
The technique, says MIT, could make recharging an electric vehicle as quick and easy as filling a gas tank.
Drivers could simply ‘refuel’ the battery by pumping out the liquid slurry and pumping in fully charged replacement, or by swapping out the tanks like tires at a pit stop.When there’s time, they could also recharge the existing material.
Existing flow batteries take up much more space than fuel cells and require rapid pumping of their fluid, further reducing their efficiency.
But the MIT version is claimed to provide ten times the energy density, and half the manufacturing cost of conventional lithium-ion batteries. Because the material has such a high energy density, it doesn’t need to be pumped rapidly to deliver its power.
The key to the new battery was the realization that it would be possible to combine the basic structure of aqueous-flow batteries with the proven chemistry of lithium-ion batteries by reducing solid materials to tiny particles that could be carried in a liquid suspension.
“We’re using two proven technologies, and putting them together,” says professor of materials science W Craig Carter.
The technology is being licensed to a company called 24M Technologies, founded last summer by Carter and fellow professor Yet-Ming Chiang, along with entrepreneur Throop Wilder. The company has already raised more than $16 million in venture capital and federal research financing.