Self-assembling Nanotech Batteries

Lynne Kiesling

I’ve often wondered how nanotechnology can contribute to increased efficiency, load factor, and conservation of energy. My first thoughts were probably wrong; we don’t need nano-scale devices to perform remote monitoring and automated repair and self-correction within the wires network itself. Regular small-scale devices can do just fine for that.

But here’s some very interesting nano research that holds some promise for the holy grail of electrical energy, which is storage: self-assembling nanotech batteries.

Self-assembly is attractive because it could potentially reduce manufacturing costs and allow molecular-level control of the structure of the batteries, leading to materials and devices not easy to make using conventional manufacturing methods. Self-assembly has already been used to create a number of materials and a handful of simple devices, including half a battery.

This is pretty cool for a lot of reasons. Many people worrying about power storage worry at a much larger scale — ways to store megawatts of wind-generated power, for example, for later use — while this technology would enable more power storage at lower levels within devices themselves, in teeny weeny crevices. It’s also cool at a pure science level, because to achieve this outcome the researchers developed a deeper understanding of how the materials they used exert small forces on each other at extremely small distances, and how they could exploit these short-range forces to create potential, which is what you need for storage. [OK, you scientists out there, remember I am not a scientist, so don’t rip me apart for that one — ed.]

The researchers used lithium cobalt oxide and microbeads of graphite for the electrodes–materials commonly used in lithium-ion batteries–pairing them with a carefully selected liquid electrolyte. The electrolyte serves as an insulator, allowing ions to shuttle between the electrodes but forcing electrons to move through an external circuit, where they can be used to power a device.

In the researchers’ prototype battery, the graphite microbeads pack together to form one electrode and connect to a platinum current collector, all the while staying clear of the lithium cobalt oxide that forms the other electrode. The researchers tested the battery and showed that it could be both discharged and recharged multiple times.

As you would expect, at this time self-assembling batteries are not competitive on either storage intensity or on cost. But they do use space more efficiently than existing batteries, so these batteries would be likely to find their first uses in applications where the relative value of space is high.