A team led by Sandia National Laboratories researcher Jianyu Huang created the smallest battery in the world, with a single nanowire 7000 times thinner than a human hair as an anode. The battery was formed inside a transmission electron microscope (TEM) at the Center for Integrated Nanotechnologies (CINT) to allow researchers to better understand the anode’s characteristics.
“This experiment enables us to study the charging and discharging of a battery in real time and at atomic scale resolution, thus enlarging our understanding of the fundamental mechanisms by which batteries work.”, says Huang.
Nanowire technology used in lithium based batteries could offer significant improvements in power and energy density, ultimately leading to a whole new generation of hybrids, laptops, mobile phones, etc.
“What motivated our work,” says Huang, “is that lithium ion batteries [LIB] have very important applications, but the low energy and power densities of current LIBs cannot meet the demand. To improve performance, we wanted to understand LIBs from the bottom up, and we thought in-situ TEM could bring new insights to the problem.”
Battery research groups often use nanomaterials as anodes, but they use them in bulk rather than individually, a process elegantly defined by Huang as “looking at a forest and trying to understand the behavior of an individual tree”. The nanobattery created by the researchers practically consists of a tin oxide nanowire anode 100 nanometers thick and 10 micrometers long a bulk lithium cobalt oxide cathode three millimeters long, and an ionic liquid electrolyte; it’s pretty much the most basic battery you can build. The work can also be conducted with other kind of materials for anode or cathode studies.
“The methodology that we developed should stimulate extensive real-time studies of the microscopic processes in batteries and lead to a more complete understanding of the mechanisms governing battery performance and reliability,” he said. “Our experiments also lay a foundation for in-situ studies of electrochemical reactions, and will have broad impact in energy storage, corrosion, electrodeposition and general chemical synthesis research field.”