An MIT spin-off says it’s on track to do the near-impossible task of making an electric car battery that offers three times as much energy for a fraction of the cost.
SolidEnergy Systems Corp. says its new battery will take a page from the early days of lithium battery development, using a lithium-metal electrode to double or even triple the driving range of an electric car. If successful, it could also make EVs more affordable and therefore, more commonplace, around the world.
“If this is true, it’s the automotive equivalent of finding the Holy Grail,” Thilo Koslowski, vice president and distinguished automotive analyst for Gartner Inc., told Design News. “It would mean that the internal combustion engine wouldn’t make sense anymore.”
SolidEnergy’s new battery was spun out of the lab of prominent battery developer, Donald Sadoway of MIT. “We have the technology to achieve big numbers,” Sadoway says.
The “if” factor still looms large, however. Since the late 1980s, battery makers have made notoriously ambitious predictions about their battery chemistries, ranging from sodium-sulfur and nickel-iron to nickel-metal hydride and lithium-air. In most cases, the chemistries delivered far less than what was promised.
SolidEnergy Systems’ battery is noteworthy, however, because it emerged from the labs of one of the country’s most prominent battery developers, Donald Sadoway. Sadoway, the John F. Elliot Professor of Materials Chemistry at MIT, has been named to TIME's 100 Most Influential People in the World list and has had one of his battery projects funded by Bill Gates. At SolidEnergy, Sadoway serves as senior advisor to the MIT students from his lab, who spun off the company.
SolidEnergy’s battery serves as a prime example of what Sadoway calls “extreme electrochemistry.” It aims, not for the typical 20% improvement over existing chemistries, but for a major transformation of battery technology. To do so, it uses a lithium-metal anode, which offers far more energy than the graphite anodes often used in today’s lithium-ion batteries.
In truth, the lithium-metal electrode is an old idea, dating back to the invention of lithium-ion batteries in the 1970s by legendary battery developer, John Goodenough. But lithium-metal long ago fell out of favor because electrolytes were found to be unstable in their presence, raising the risk of fire. As a result, material scientists turned to graphite, which was far less energetic but infinitely more stable.
Still, engineers at SolidEnergy say they’ve found a way to bring the lithium-metal electrode back, and make it more stable in the bargain. Their solution involves use of a complicated new “biphasic electrolyte” -- that is, an electrolyte that’s part solid and part liquid. By putting a solid polymer up against the lithium-metal electrode, and then employing a combination of a polymer and an ionic liquid in the vicinity of the positive electrode, they say they’ve eliminated the instability and improved the battery’s room temperature performance.