Xing estimates that if lithium-air progresses like lithium-ion, the battery used in electric cars today, it will take 15 to 20 years to go commercial. But high-risk research like his -- which may catapult the technology ahead or slam into a dead end -- could change that calendar. "Obviously, if a breakthrough technology is successful, that's going to shorten the time a lot," he said.
Xing isn't the mad inventor working on rocket packs, mechanized human wings or time machines in his garage. To most, he probably comes off like most engineering professors: bookish, private, inclined to discuss factual matters rather than tarry on questions of meaning.
Yet in this anonymity, Xing has advanced science that could turn the dawn of the electric car into an era. It's sprung from careful, plodding chemistry, at the intersection of fuel cells and batteries, that he and a half-dozen graduate students have worked on for six years.
Finding its way to the ultimate risk-taker
A couple years ago, he realized this work could apply to lithium-air, already known as the holy grail of the field. Yet when he floated the idea to a few business contacts, they hedged. There was no guarantee the research would succeed, they pointed out, and the professor had no prototype to prove he could turn math into machines. Xing's idea was stranded.
Then ARPA-E was born, and he sensed a rare opportunity. So he called up some of his contacts from over the years -- a government lab, a small battery company, a nanotechnology research firm -- and decided to try his chances.
Xing's group was up against 220 other battery proposals, including plans from Stanford University, the Massachusetts Institute of Technology and companies with deep roots in government labs. Yet his idea made the final cut of 10 projects.
Now he has a $1.2 million grant to use over three years. After he hires some more researchers, the entire team will have about a dozen people.
So how exactly does one search for a breakthrough? Xing is cagey. Asked to expand on the specific work he's doing, he said he can't discuss the technical details of his research. He only said he's developing a new electrode and a new catalyst for lithium-air.
This is about as specific as a jet designer saying he's working on a new type of engine. But Xing isn't the only one treating his ARPA-E project sensitively. The other lithium-air awardee, PolyPlus Battery Company Inc., a spinoff from Lawrence Berkeley National Laboratory considered a world leader in the technology, didn't return ClimateWire's messages. Two other ARPA-E awardees, each working on other types of cutting-edge batteries, declined to talk to ClimateWire.
What is known about Xing's work is that it focuses on the major scientific challenges that keep lithium-air from practicality.
Most batteries are self-contained units. They hold materials whose chemical relationship essentially kicks electrically charged particles called ions from one side of the battery to the other. When ions get punted one way, the battery generates electricity; when they go the other direction, the battery stores energy.
Lithium-air batteries work similarly, but they aren't self-contained units. One of the "kickers" is actually a doorway to the outside world. It's a porous sheet whose only job is to let oxygen in, because that drives the chemical reactions that keep the kicking game going. This sheet takes up a lot less space than the solid material needed in other batteries, like iron, cobalt or manganese. Voilà: The battery holds just as much energy, but would take up a fifth of the space of lithium-ion batteries used in today's electric vehicles.
That sounds basic, but no one has found the right recipe yet. Indeed, scientists are still working out the basics.
What a 'breakthrough' has to be
Xing and his team are working on two aspects. The first is using nanotechnology to make a porous sheet that "breathes" oxygen more efficiently. The other challenge is finding a material that binds oxygen just as easily as it lets oxygen go; otherwise, the battery's not rechargeable, and it's useless for electric cars.