Zothecula writes "Because battery technology hasn't developed as quickly as the electronic devices they power, a greater and greater percentage of the volume of these devices is taken up by the batteries needed to keep them running. Now a team of researchers working at the Center for Integrated Nanotechnologies has created the world's smallest battery. 'It consists of a bulk lithium cobalt cathode three millimeters long, an ionic liquid electrolyte, and has as its anode a single tin oxide (Sn02) nanowire 10 nanometers long and 100 nanometers in diameter.' (Abstract in Science.) Although the tiny battery won't be powering next year's mobile phones, it has already provided insights into how batteries work and should enable the development of smaller and more efficient batteries in the future."