SANTA CRUZ, Calif. ó Amprius Inc. (Sunnyvale, Calif.), a Stanford University spinoff, revealed the secrets behind its lithium ion technology that claims to boost energy density by 10-times over conventional batteries at the Global Press eSummit 2013 (April 14-17, here). By perfecting the topology of silicon-nanowire anodes, compared with the carbon-based anodes used today, Amprius promises to boost the battery lifetime of mobile devices by 2014, with automobile batteries on the roadmap by the end of the decade.
"Electron transport in lithium ion batteries can be greatly enhanced by going to silicon-nanotube anodes," said founder of Amprius, Stanford University professor Yi Cui. "But first you need to overcome the expansion problem with silicon."
Silicon nanowire anodes for lithium ion batteries can handle 10-times the current of conventional carbon anodes, but in operation silicon also expands by as much as four-times, which can cause conventional topologies to fail. The solution, according to Cui, is to use sparsely spaced nanowires with a mechanical clamping layer on top, which accommodates the expansion without breaking the anode.
Lithium-cobalt-oxide cathodes paired with silicon-nanowire anodes can increase the power density of traditional lithium ion batteries to 4200 mAh/g, about a 10-time boost. SOURCE: Amprius
Amprius' current prototypes not only offer 10-times the energy density, but also can be charged-and-discharged in thousands of cycles instead of the hundreds of cycles typical of conventional lithium-ion batteries.
Amprius is manufacturing its new batteries in China and promises that its first customers will be delivering cell phones with expanded lifetime battery by 2014, with automobile batteries slated to follow in a few years.