New architecture promises better battery
R Colin Johnson
8/11/2011 1:24 PM EDT
How's it work?
Ioxus' hybrid ultra-capacitors combine the architecture of a capacitor—charge accumulating on plates separated by an insulator—with the chemical storage of a lithium-ion battery. Using the same chemistry as a lithium-ion battery, the hybrid ultra-capacitor distributes those chemicals onto the surface of a solid electrode, rather than embed the chemicals into a porous electrode where the slow process of intercalation is required to charge and discharge them.
As a result, Ioxus' hybrid ultra-capacitors can be charged and discharged at nearly any rate—allowing them to swallow-up and discharge-out vast or minuscule currents as required by an application. Their only downside is that they cannot store as much charge volume as a traditional battery, nor store it for as long, but the distributed architecture used by applications compensates for these shortcomings, according to Ioxus.
Ioxus hybrid ultracapacitors with built-in lithium-ion batteries enables distributed storage archtectures that works better than either technology alone.
"Hybrid capacitors can be added to supply energy right where it is needed," said Hall. "They store more energy than an ultracapacitor alone, and can endure nearly unlimited numbers of charge-discharge cycles compared to lithium-ion batteries."
Hybrid ultra-capacitors do not store as much charge as a lithium ion battery, but they do store about 100 percent more charge than an ultra-capacitor alone, plus provide almost unlimited charge/discharge cycling. Most lithium ion batteries can only be charged/discharged a few hundred times, and even special long-term versions are limited to a few thousand cycles. Hybrid ultra-capacitors, on the other hand, typically can be charged and discharged more times than the lifetime of the product in which they are being used—more than 20,000 cycles in tests conducted at Ioxus.
Hybrid ultra-capacitors also offer much more instant-on power than even the strongest battery—up to 5 kiloWatts per kilogram compared with 3kW/kg for even the highest priced batteries, according to Ioxus, which also claims that its hybrid ultra-capacitors are 95 percent energy efficient, compared with 70 percent for the best lithium ion batteries.