MIT Spinoff Develops Battery With Double Li-Ion Energy Density

Massachusetts-based SolidEnergy Systems Corp. says it has developed a lithium-metal battery with around twice the energy density of the cells in a Tesla Model S and it needs no thermal management, thus is cheaper.

The MIT spinoff says its battery cells demonstrated volumetric energy densities at high as 1,337 Wh/L when tested by another MIT spinoff, A123 Systems, which performed an independent third-party analysis.

By doing away with liquid coolant and metal hardware normally needed to control temperatures for the low-volatility chemistry, SolidEnergy says pack costs could be cut to $130 per kilowatt-hour compared to $300-$500 more commonly paid today.

What’s that catch? None yet, except that batteries take time to develop from lab stage to automotive-ready stage, and for those wanting 400-mile range EVs with $30,000 sticker prices, this chemistry is unfortunately in the lab stage.

A likely early use will be in portable devices aside from more involved automotive propulsion applications.

A likely early use will be in portable devices aside from more involved automotive propulsion applications.

Encouraging is the fact that SolidEnergy Systems is run by students of Donald Sadoway, a John F. Elliot Professor of Materials Chemistry at MIT named to TIME’s 100 Most Influential People in the World list.

According to Design News, which reported the story, and interviewed Sadoway, an analyst and other knowledgeable commentators, Sadoway has also had one of his battery projects funded by Bill Gates, and he describes it as “extreme electrochemistry.”

The actual concept is not new however. It is a revival of chemistry shelved decades ago because it was deemed too much a fire hazard, but the company says it has solved former problems.

In the 1970s electrolytes were unstable in the presence of metal electrodes, so less energetic but more stable graphte was used for li-ion batteries in use today.

The company turned to a part solid, part liquid “biphasic electrolyte” which uses an ionic liquid and a polymer in the vicinity of the positive electrode and stability and thermal runaway are no longer a concern.

The biphasic electrolyte utilizes a solid polymer on one side, and a solid polymer and ionic liquid on the other side. (Image: SolidEnergy Systems Corp.)

The biphasic electrolyte utilizes a solid polymer on one side, and a solid polymer and ionic liquid on the other side. (Image: SolidEnergy Systems Corp.)

Instead, room temperature performance is improved, while providing a substantial increase in energy density – for example the new Chevy Volt’s battery is 20-percent improved, a more-typical increase level.

Sadoway told Design News that what’s needed next are people who can scale up from lab to production, but he believes they have the technology in place.

Specific performance numbers have not been published however, so while vouched for anecdotally by the distinguished professor and his team, experts are on hold before getting overly excited.

If all goes to plan, Thilo Koslowski, vice president and distinguished automotive analyst for Gartner Inc., told Design News this could be a “Holy Grail” relegating internal combustion engines to no-longer relevant status.

And while saying there is not enough published data to start celebrating, Elton Cairns, professor of chemical engineering at the University of California-Berkeley and developer of fuel cells for the Gemini space program in the 1960s said, “Conceptually, there’s nothing wrong with the idea.”

So, it’s wait and see, and could be just a matter of time.

Design News, Press Release


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