Graphic illustrating the redesigned cathode and anode.
(Credit: Beckman Institute for Advanced Science and Technology)
A new lithium-ion micro-battery is just millimetres in size, can jump-start a car battery and recharges in less than a second.
One of the biggest bugbears of smartphones is just how much juice they drain — and how long they take to recharge. Batteries are also the reason that many devices can't be smaller; after all, they have to fit somewhere (although, given the burgeoning phablet market, that's not exactly a huge problem).
A team of researchers, led by William P King at the University of Illinois in Urbana-Champaign has developed a new type of lithium-ion battery that is just a fraction of the size of the batteries we use now — and which can out-power the best supercapacitors.
They have done this by redesigning the cathode and anode — these are the positive (cathode) and negative (anode) poles of the battery. In a traditional battery, these poles are solid. In the University of Illinois' battery, they've redesigned these poles so that they're porous, three-dimensional microstructures.
Simply changing the structure this way gives the battery a power density up to 7.4 mW cm−2 μm−1 — which is equal to or greater than that of supercapacitors, and 2000 times higher than that of other micro-batteries. It also means that the battery can charge up to 1000 times faster than competing technologies.
They're not quite ready for the market just yet, though. At such a tiny size, they will be difficult to integrate with current devices — and manufacturing cost is a little on the high side. But it does mean interesting things for the future.
"Now we can think outside of the box. It's a new enabling technology. It's not a progressive improvement over previous technologies; it breaks the normal paradigms of energy sources. It's allowing us to do different, new things," said James Pikul, graduate student and first author of the paper.
The full paper, "High-power lithium-ion micro-batteries from interdigitated three-dimensional bicontinuous nanoporous electrodes", is available in Nature Communications.