Steve Martin had a comedy routine that focused on the idea of “getting small.” That probably didn’t inspire the researchers at the Institute for Integrative Nanoscience when they set out to create a sub-square-millimeter microbattery. As you might expect, you won’t be starting your car with a battery the size of a grain of sand anytime soon, but these batteries do have a surprising capacity.
The key is creating what they call “micro-swiss rolls” where the electrodes are wrapped in a tiny cylinder. This isn’t a new idea. However, creating workable rolls at the scale where a grain of rice looks huge isn’t trivial.
Combining a zinc wire and manganese dioxide in tiny proportions makes the battery possible. The manufacturing process is novel and involves making a slurry of the MnO2 with a solvent. Placing the diminutive swiss roll on a glass substrate allows tiny circuits to exist along side of the battery. The battery itself is about the size of common SMD components, but the circuits it will power are likely more like tiny IC dice.
Building a better battery isn’t a new pursuit, although usually, you aren’t going for tiny. We are always a sucker for novel battery tech, even though most of what we read about never shows up on the store shelves.