Stanford University Materials Science Asst. Prof Yi Cui had developed what is claimed to provide a breakthrough in electrical energy storage. Instead of having an anode comprised of a solid mass of silicon and carbon, Cui and his research team have developed one based on a bundle of silicon nanowires. The limiting factor of traditional designs is that the as the silicon absorbs the lithium ions during charging, it swells and then contracts during discharge. Over time this causes the anode to crack, reducing the battery's capacity. The work done by companies like Altairnano and A123 is based on the same principle of using nano-sized materials that can absorb the lithium ions and have room to expand. Cui is claiming his nanowire design can improve the battery storage capacity by a factor of ten. The photo above shows an anode before and after charging at the same magnification.
[Source: Stanford News]