AT A GLANCE ENERGY STORAGE
SOLID POWER Developing solid electrolytes for safer, high-energy batteries
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⚫ Launched: 2012 ⚫ Headquarters: Louisville, Colo. ⚫ Focus: Battery materials ⚫ Technology: Sulfide-based solid electrolytes ⚫ Founders: Doug Campbell, Sehee Lee, and Conrad Stoldt ⚫ Funding or notable partners: In the process of raising $15 million
of developing cathode materials based on utomakers have their pedals to the their research at CU Boulder. But in 2016, metal when it comes to developing aenm.201602011). “You have to design the firm switched to sulfide-based solid battery-powered cars, but electroaround that knowledge,” McGrogan notes. electrolytes after securing an exclusive lichemists still have their work cut Solid Power says low-temperature proout to deliver the battery performance and cense to commercialize technology develcessing of its electrolyte allows it to use oped by Oak Ridge National Laboratory. safety that large-scale adoption requires. polymer binders that mitigate brittleCampbell is convinced Solid Power is Current lithium-ion batteries typically opness. Meanwhile, the firm’s proprietary developing the right technology at the erate with a lithium-ion cathode, graphite electrode and electrolyte separator right time. “The automotive industry is anode, and liquid electrolyte. But liquid chemistry and coating process really starting to embrace the concept of electrolytes can become dangerously hot ensure efficient transfer of lithsolid-state batteries,” he says. and catch fire. A safer solution—and one ium ions between electrodes, Historically, a problem with sulthat could also facilitate greater energy density—is to switch to a solid electrolyte. fide-based electrolytes has been the materi- Campbell says. A couple of months al’s brittleness, which can cause structural Solid Power, a spin-off from the Uniago, Solid Power reloproblems in a battery, according to Frank versity of Colorado, Boulder, claims its cated to Louisville, P. McGrogan, a Ph.D. candidate at Maslithium-sulfide solid electrolyte can be Colo. There, the firm is sachusetts Institute of Technology who produced at about the same cost as a liqstarting to install what published research on the topic earlier this uid electrolyte. And batteries containing the solid electrolyte can store more energy year (Adv. Energy Mater. 2017, DOI: 10.1002/ it calls prepilot production facilthan traditional batteries of ities where the same size. it can make In tests, Solid Power’s hundreds of auelectrolyte operates safely When a lithium-ion battery charges and discharges, the ions tomotive-scale battery at temperatures of about flow through its electrolyte between its electrodes. Solid Power cells per month. 150 °C—an environment in is trying to use sulfur-based solid electrolytes, which are safer The firm recently initiwhich many liquid electroat higher temperatures than flammable liquid electrolytes are. ated a series A financing lytes would catch fire. Unlike liquid-electrolyte batteries, which use carbon or graphite round led by the battery Combining the electroanodes, solid electrolytes can also be used with a lithium metal manufacturer A123 Systems lyte with a lithium metal anode, markedly boosting energy density. to raise $15 million to fund anode can bring the energy + research and outfit the density of Solid Power’s firm’s new battery assembattery cells to 400– bly center. 500 Wh/kg. This is more Solid Power already has than twice the density of a multi-million-dollar joint conventional liquid-elecdevelopment agreement trolyte cells that use stanwith one European car comdard graphite anodes, says Cathode pany and is looking to add CEO and cofounder Doug Anode similar deals. Its goal is to Campbell. get solid-state batteries into Its two other cofoundSolid electrolyte commercial electric cars in ers, Conrad Stoldt and Sehthe next five to 10 years. ee Lee, started the com+ Li Solid electrolyte batpany in 2012 with the aim teries can be very strong, and someday they could actually form part of a car’s structure. In the meantime, Solid Power is working to roll out solid-state cells for niche military and aerospace applica– tions.—ALEX SCOTT
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C&EN | CEN.ACS.ORG | NOVEMBER 6, 2017
C R E D I T: C& E N /S H UT TE RSTO CK
Solid state
