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Energy Storage

Solid Power wins $12.5 million for FeS₂ cathodes

Renewed iron-sulfide research will supplement commercialization work on solid sulfide electrolyte

by Craig Bettenhausen
October 1, 2021


A photo of a chunk of pyrite being held by a bearded man; only the pyrite is in focus.
Credit: Solid Power
Solid Power senior research scientist Brian Francisco holds a sample of FeS2, a cheap and common mineral known as pyrite or fool's gold.

The solid-state battery start-up Solid Power has secured up to $12.5 million in federal funding to develop iron sulfide cathodes. The investment comes from the Intelligence Advanced Research Projects Activity (IARPA), which is part of the US Office of the Director of National Intelligence.

This funding comes at a busy time for Solid Power. The company is in the midst of commercializing its sulfide-based solid electrolytes and pouch-cell batteries, and has successfully secured electric vehicle partnerships with BMW and Ford. The firm is also going public later this year by way of a merger with a special-purpose acquisition company, or SPAC. The deal values Solid Power at $1.2 billion.

The work on FeS2 cathodes takes the company, one of C&EN’s 10 Start-Ups to Watch in 2017, back to its earlier days. “Solid Power got its start—and spun out of the University of Colorado—with research and work on this cathode material,” says the firm’s communications director, Will McKenna. The funding from IARPA will allow Solid Power to direct resources and personnel toward the cathode work even in this busy season for the company, he says.

Cathodes are the priciest part of most lithium-ion batteries, largely because of the cost of the nickel and cobalt in industry-standard cathodes, which Solid Power’s batteries currently use. Solid Power says that using FeS2 could reduce cathode material costs by 90%, from $35 per kWh to $3 per kWh. Moreover, the finished batteries could beat conventional designs in terms of energy storage capacity and lifetime.

McKenna emphasizes, however, that the FeS2 work is at the R&D stage. The research, which will be a collaboration with the University of Maryland, “will help us as we look to transition the chemistry to the automotive market in the future,” McKenna says. “We have not set a timeline for testing for automotive applications at this time.”



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