They may be as small as grains of salt, but US researchers are developing batteries that pack the power of their larger kin.
Although they likely won't appear anytime soon in your laptop or smart phone, these tiny batteries could eventually power everything from microrobots to medical implants.
"We're trying to achieve the same power densities, the same energy densities as traditional lithium-ion batteries," says Jane Chang, an engineer at the University of California, Los Angeles, developing the new batteries.
Chang presented her findings this week at the AVS 57th International Symposium & Exhibition.
The key to these tiny batteries is their architecture. The UCLA scientists start with a field of tiny nanowires. Then they deposited layers of nano-sized lithium aluminosilicate to those nanowires, creating a three-dimensional structure.
Most batteries today have a two-dimensional structure. Expanding up, instead of just out, means the battery can hold more energy in a smaller space.
The textured surface also increases the surface area of the battery, making it easier to pass power between the battery's components and an electrolyte, the conductive material that allows current to flow.
Powering miniature sensors
Batteries that are the size of a grain of salt - or smaller - could power sensors that detect viruses, chemicals and more, says Philip Collins, a scientist at the University of California, Irvine.
"We can make sensors the size of a grain of sand or smaller, but we don't have a good way to power those sensors," for months or even years, says Collins.
Eventually these microscopic batteries will power microscopic robots as well.
Although the design is promising, Chang and her colleagues have yet to construct this tiny battery. The anode and the cathode of the battery have already been built, but the pieces still need to be assembled and tested.