Lithium ion batteries are quickly becoming the standard for high energy density, making their way into everything from laptops to Tesla’s Model S. And while I’m very interested in breakthroughs in battery technology because the ability to store energy relatively cheaply would transform the global energy economy, I tend not to pay too close attention to the laboratory advances, given the reality that commercialization of any lab breakthrough is as hard, or harder, than the laboratory discovery.
But with that all said, the recent news that a team at the engineering school at USC had developed better materials for the cathode and anode of a lithium ion battery is potentially important. From the report:
Traditionally, lithium-ion batteries contain a graphite anode, but silicon has recently emerged as a promising anode substitute because it is the second most abundant element on earth and has a theoretical capacity of 3600 milliamp hours per gram (mAh/g), almost 10 times the capacity of graphite. The capacity of a lithium-ion battery is determined by how many lithium ions can be stored in the cathode and anode. Using silicon in the anode increases the battery’s capacity dramatically because one silicon atom can bond up to 3.75 lithium ions, whereas with a graphite anode six carbon atoms are needed for every lithium atom.
The USC Viterbi team developed a cost-effective (and therefore commercially viable) silicon anode with a stable capacity above 1100 mAh/g for extended 600 cycles, making their anode nearly three times more powerful and longer lasting than a typical commercial anode.
The team is now testing the cathode and anode together to integrate the two technologies. A lot of next generation battery technology research is focused on innovating the core battery electrolytes (the solution through which the ions pass). But the USC lab’s approach is interesting in that it’s attempting to optimize a technology that’s already widely available. Should we ever get a stepwise improvement in cathode/anode technology, it would be a major boost to the already growing lithium ion battery market.