“World’s fastest electrodes” triple the density of lithium batteries

French company Nawa technologies says it’s already in production on a new electrode design that can radically boost the performance of existing and future battery chemistries, delivering up to 3x the energy density, 10x the power, vastly faster charging and battery lifespans up to five times as long.

Nawa is already known for its work in the ultracapacitor market, and the company has announced that the same high-tech electrodes it uses on those ultracapacitors can be adapted for current-gen lithium-ion batteries, among others, to realize some tremendous, game-changing benefits.

It all comes down to how the active material is held in the electrode, and the route the ions in that material have to take to deliver their charge. Today’s typical activated carbon electrode is made with a mix of powders, additives and binders. Where carbon nanotubes are used, they’re typically stuck on in a jumbled, “tangled spaghetti” fashion. This gives the charge-carrying ions a random, chaotic and frequently blocked path to traverse on their way to the current collector under load.

The benefits are all about how far an ion has to carry its charge; on the left, a depiction of a typical, chaotic electrode structure through which an ion has to travel long and circuitous distances. On the right, the rigid structure of a vertically aligned carbon nanotube structure, which links every tiny blob of active material and the ions within straight to the current collector

The benefits are all about how far an ion has to carry its charge; on the left, a depiction of a typical, chaotic electrode structure through which an ion has to travel long and circuitous distances. On the right, the rigid structure of a vertically aligned carbon nanotube structure, which links every tiny blob of active material and the ions within straight to the current collector
Nawa Technologies

Nawa’s vertically aligned carbon nanotubes, on the other hand, create an anode or cathode structure more like a hairbrush, with a hundred billion straight, highly conductive nanotubes poking up out of every square centimeter. Each of these tiny, securely rooted poles is then coated with active material, be it lithium-ion or something else.

The result is a drastic reduction in the mean free path of the ions – the distance the charge needs to travel to get in or out of the battery – since every blob of lithium is more or less directly attached to a nanotube, which acts as a straight-line highway and part of the current collector. “The distance the ion needs to move is just a few nanometers through the lithium material,” Nawa Founder and CTO Pascal Boulanger tells us, “instead of micrometers with a plain electrode.”

This radically boosts the power density – the battery’s ability to deliver fast charge and discharge rates – by a factor of up to 10x, meaning that smaller batteries can put out 10 times more power, and the charging times for these batteries can be brought down just as drastically. Nawa says a five-minute charge should be able to take you from 0-80 percent given the right charging infrastructure.

[…]

“Research has shown vertically aligned – or even just well distributed – carbon nanotubes have far greater properties than randomly placed carbon nanotubes,” said Dr. Shearer. “I am not surprised a x10 in conductivity is possible. Controlling the placement of carbon nanotubes is really the way to unlock their potential. The issue in commercialization is the cost associated with producing aligned carbon nanotubes. My guess is the cost would be much more than x10.”

We put the question of cost to Nawa. “The million dollar question!” said Boulanger. “Here’s a million dollar answer: the process we’re using is the same process that’s used for coating glasses with anti-reflective coatings, and for photovoltaics. It’s already very cheap.”

“In high volume, like those processes, yes,” added Nawa CEO Ulrik Grape. “We are firmly convinced that this will be cost-competitive with existing electrodes.”

[…]

In some cases, Nawa says, it eliminates issues that have been holding back certain other battery chemistries. Silicon-based batteries, for example, could offer around twice the energy density of lithium-ion, but the active material grows to four times its size as it’s charged and shrinks back again as it discharges, causing mechanical issues that lead to cracks. As a result, you might be lucky to get 50 charges out of a silicon battery before it dies.

[…]

Moving to these electrodes, Grape and Boulanger say, will require battery companies to make some fairly considerable changes to the early stages of their manufacturing processes prior to cell assembly. But such dramatic performance multipliers without a price penalty or any changes to battery chemistry will surely make these things tough to compete against.

Nawa’s first large-scale customer is French battery manufacturer Saft, which is partnering with PSA and Renault as part of the European Battery Alliance to develop EV batteries for the brands under those umbrellas. The company is also speaking to a number of car companies directly, as well as other battery manufacturers supplying the EV space.

Source: “World’s fastest electrodes” triple the density of lithium batteries