November 11th, 2014 by Tina Casey
A team of researchers at the University of Maryland has come up with an elegantly simple nanoscale battery concept that they’re describing as the “ultimate miniaturization of energy storage.” The team isn’t just tooting its own horn. They already have assembled a working model of the initial design and they’re developing a more powerful version with an eye toward producing it in large batches.
Schematic of “nanopore battery” (courtesy of NEES, a DOE Energy Frontier Research Center)
The Vanadium–Energy Storage Connection
The secret sauce in the “nanopore battery,” as they’re calling it, is a compound of the silvery transition metal vanadium. Vanadium is best known for its use in steel alloys, but lately it’s been popping up all over the place in clean tech applications, particularly in energy storage and next-generation EV charging.
That makes vanadium a critical material for growing the domestic clean tech industry, but the sticky wicket is where to get the vanadium. Until very recently, there were no vanadium mines in the US.
The good news is, that’s changing practically overnight. The aptly named Canadian company American Vanadium is developing a vanadium mine in Nevada, and another company on our radar, Imergy, has figured out how to cull high-quality vanadium from mine tailings and other waste sources.
The UMD “Ultimate” Miniature Energy Storage Concept
Now that we got that out of the way, let’s take a closer look at the UMD breakthrough, which has just been published in the journal Nature.
The battery consists of an array of identical nanoscale holes, aka “nanopores,” stamped into a ceramic surface (for those of you new to the topic, nano refers to a billionth of a meter).
Each pore is itself a super-miniature battery complete with an electrolyte as well as an anode and a cathode made from the transition metal ruthenium and vanadium oxide, a compound of vanadium. As you can imagine the storage capacity is on the small-to-practically-useless side individually, but set up an array of these things and now you’re talking energy storage on a useful scale.
When you consider that about a billion nanopores can fit into a wafer the size of a postage stamp, now you’re cooking with gas.
Zoom out from the black and white image below and you’ll get an idea of what the battery would look like in real life, namely, nothing like any battery you’ve ever seen before.
Here’s the research team enthusing over the possibilities:
From a fundamental point of view, our all-in-one nanopore battery array unveils an electrochemical regime in which ion insertion and surface charge mechanisms for energy storage become indistinguishable, and offers a testbed for studying ion transport limits in dense nanostructured electrode arrays.
By the way, did you notice how we slipped ruthenium in there? Ruthenium supply could become an issue moving forward, but the last time we checked, the global ruthenium market was looking pretty good for energy storage applications.
According to our friends over at Platts, the advent of cloud computing has dampened down the demand for ruthenium in the computer industry, freeing up the supply pipeline for other uses.