Researchers at Sandia National Laboratories have developed a world's smallest battery. Lithium ion batteries have very important applications, but the low energy and power densities of current designs cannot meet the demand. To improve performance, the researchers have used nanomaterials as anodes in bulk and demonstrated a tiny rechargeable, lithium-based battery formed inside a transmission electron microscope (TEM).
The tiny battery created by researchers consists of a single tin oxide nanowire anode 100 nanometers in diameter and 10 micrometers long, a bulk lithium cobalt oxide cathode three millimeters long, and an ionic liquid electrolyte.
Researchers found that the tin oxide (SnO2) nanowire rod nearly doubles in length during charging far more than its diameter increases. This is due to the fact that as lithium ions travel along the nanowire they create an area where high density of mobile dislocations causes the nanowire to bend and wiggle as the front progresses. The web of dislocations is caused by lithium penetration of the crystalline lattice, thus nanowires can sustain large stress induced by lithiation without breaking. This indicates that nanowires are very good candidates for battery electrodes giving scope for high-energy battery design and for mitigating battery failure.