It's almost a cliche that the missing piece of a renewable energy future is low-cost energy storage.
"Until we find a technology that is low-cost, highly scalable, and long-lasting, ubiquitous grid storage won't be possible. The all-liquid battery's elegant materials design and simple assembly process makes it the best chemical option we've seen for storing the grid at massive scale."
That's Khosla Ventures partner Andrew Chung's comment on Liquid Metal Battery Corporation (LMBC). He's now on the board of the firm; he funded founder Don Sadoway's research at MIT before the firm won the top ARPA-E award back in 2009.
LMBC just announced that it raised an additional $15 million in funding in its Round B from Khosla Ventures, Bill Gates and energy company Total.
We spoke with Phil Giudice, the CEO of LMBC, as well. He said, "Our Liquid Metal Battery technology is tremendously exciting because it has the potential to dramatically change the electric power system everywhere," in a release. The CEO told GTM that the company had passed the R&D stage and was moving into commercializing the technology for large-scale grid applications.
The inventor of the core technology for the battery is Don Sadoway, MIT Professor of Materials Chemistry, one of MIT's most popular professors and sought-after speakers. Sadoway has challenged the research community to invent a colossal yet cheap battery. He directed researchers to look at the economy of scale of modern electrometallurgy and the aluminum smelter, which handles the holy grail of batteries: achieving a high current while maintaining massive scale.
Why is an aluminum cell not a battery? You have to produce liquid metals at both electrodes.
Making metal at the cathode is trivial, but making metal at the anode is not so trivial. So Sadoway went back to the periodic table and used magnesium to "intimidate" antimony into behaving like a non-metal. From there, using seed money from within MIT, Sadoway and his team invented the liquid metal battery or, more academically, a process called Reversible Ambipolar Electrolysis.
The battery uses molten antimony and molten magnesium separated by an electrolyte. Sadoway claims that the all-liquid configuration is self-assembling and is expected to be scalable at low cost. Furthermore, this technology may have a shot at being cheaper than sodium sulfur (NaS) batteries.
Sadoway has spoken about how rechargeables have improved as we progressed from lead acid at 35 Wh/kg to Li-ion at 150 Wh/kg (versus gasoline at 12,000 Wh/kg). But Sadoway doesn't think that Li-ion batteries have a future in grid-scale or transportation applications. We need to change chemistries and that takes radical innovation, according to Sadoway, in order to make solar and wind power more dispatchable. In this case, we need to make a battery that can handle high current.
Lithium-ion batteries in phones and cars have to be ultra-safe. Cell phones "need to be idiot-proof, largely because they are in the hands of idiots," and batteries in cars need to be able to withstand a crash. Stationary batteries for bulk storage are not held to those same requirements, which allows more freedom in choice of chemistry, but the application requires a very low price point -- and Sadoway insists that you have to think about price point at the beginning of the product design process.
It's no secret that Vinod Khosla is not a big fan of lithium-ion batteries.
Automotive traction for an all-electric car has a target cost of $100 to $200 per kWh, and stationary storage needs to be in the vicinity of $50 per kWh, according to Sadoway.
Sadoway has weighed in on the woeful state of energy research in the U.S., saying, "We need to accelerate the rate of discovery. We can make batteries two or three times better if we're willing to make the investment." He said that energy research has fallen by a factor of six, while medical research has grown by a factor of four since the 1970s. He also observes that the U.S. energy industry spends 0.25 percent of revenues on R&D, while the pharmaceuticals industry spends 18 percent and semiconductor firms spend 16 percent. Even the automotive industry spends 3 percent of its revenues on R&D.
Sadoway recommends that researchers "confine their search to earth-abundant elements. The only way to make something dirt cheap is to make it out of dirt -- American dirt."
Though revolutionary technology is a good thing, getting storage on the grid is going to involve leveraging technology, price, and, just as importantly, regulatory issues involving the FERC, and ISOs and PUCs across the nation.