Energy Storage Just Got Smaller (but Mightier!)

Researchers are building a new type of battery that is based on tiny nanopores in a ceramic material.
Published: Fri 21 Nov 2014

A team of researchers at the University of Maryland have invented a simple nanoscale battery concept – a single tiny structure that includes all the components of a battery that they say could bring about the ultimate miniaturization of energy storage components.

Battery design matters

The structure is called a nanopore - a tiny hole in a ceramic sheet of material that holds electrolyte to carry the electrical charge between nanotube electrodes at either end. In other words, each cavity acts as an individual battery cell and all of them are joined in parallel.

Many millions of these nanopores can be crammed into one larger battery the size of a postage stamp. One of the reasons the researchers think this unit is so successful is because each nanopore is shaped just like the others, which allows them to pack the tiny thin batteries together efficiently. The research team says that the battery’s unique design is responsible for its success. The space inside the holes is so small that the space they take up, all added together, would be no more than a grain of sand.

The entire design of the battery involves each of its nanobattery components being composed of an anode, a cathode, and a liquid electrolyte confined within the nanopores of anodic aluminium oxide, which is an advanced ceramic material. Each nanoelectrode includes an outer ruthenium nanotube current collector and an inner nanotube of vanadium pentoxide storage material. These together form a symmetric full nanopore storage cell with anode and cathode separated by an electrolyte region. The vanadium pentoxide is treated with lithium at one end to serve as the anode, with pristine vanadium pentoxide at the other end serving as the cathode.

Vanadium is used mostly in steel alloys, but lately it’s been used increasingly in clean tech applications, particularly in energy storage and next-generation EV charging. Until very recently, there were no vanadium mines in the US but now, this is changing fast in order to keep up with the creation of innovative technologies. Canadian company American Vanadium is developing a vanadium mine in Nevada, and another company Imergy is culling high-quality vanadium from mine tailings and other waste sources.

Battery 10 times more powerful

Now that the scientists have the battery working and have demonstrated the concept, they have also identified improvements that could make the next version 10 times more powerful. The next step to commercialization: The team of inventors have already assembled a working model of the initial design and they’re developing a more powerful version with the aim of producing it in large quantities.

Chanyuan Liu, a Ph.D. student in materials science & engineering, says that the battery can be fully charged in 12 minutes and can be recharged thousands of time.

The team of UMD chemists and materials scientists collaborated on the project include: Gary Rubloff, director of the Maryland NanoCenter and a professor in the Department of Materials Science and Engineering and the Institute for Systems Research; Sang Bok Lee, a professor in the Department of Chemistry and Biochemisty and the Department of Materials Science and Engineering; and seven of their Ph.D. students (two of whom have now graduated).

This research was supported as part of the Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science.