Faster electrodes triple the density of lithium batteries
Posted: 07 Oct 2020, 10:41
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.
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.
Nawa's vertically aligned carbon nanotubes, and 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 is then coated with active material, be it lithium-ion or something else.
The result is a 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.
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. Nawa says a five-minute charge should be able to take you from 0-80 percent given the right charging infrastructure.
Because there's gaps in that ultra-lightweight nanotube scaffolding and less extraneous binder and additive materials, a battery containing a given amount of active material can become much, much lighter and more compact. Energy density, both by weight and by volume, stands to jump by factors of 2-3.
Nawa says a battery's lifespan should be five times longer using this technology.
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.
Nawa's vertically aligned carbon nanotubes, and 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 is then coated with active material, be it lithium-ion or something else.
The result is a 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.
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. Nawa says a five-minute charge should be able to take you from 0-80 percent given the right charging infrastructure.
Because there's gaps in that ultra-lightweight nanotube scaffolding and less extraneous binder and additive materials, a battery containing a given amount of active material can become much, much lighter and more compact. Energy density, both by weight and by volume, stands to jump by factors of 2-3.
Nawa says a battery's lifespan should be five times longer using this technology.