Wednesday, September 15, 2021

Batteries: Is This The End Of Lithium-ion? (and the beginning of graphene?)

It's been eleven years since Geim* and Novoselov won the Nobel prize for graphene, it's about time someone figured out what to do with it. I mean, look at Ivermectin: Nobel Prize in Medicine 2015, stupid horse snark 2021. That's how science marches forward.

From the brainiacs at IEEE Spectrum:

Is This the End for Lithium-ion Batteries?
"Layer cake" anode could help sodium-ion batteries displace lithium-ion

After years of anticipation, sodium-ion batteries are starting to deliver on their promise for energy storage. But so far, their commercialization is limited to large-scale uses such as storing energy on the grid. Sodium-ion batteries just don't have the oomph needed for EVs and laptops. At about 285 Wh/kg, lithium-ion batteries have twice the energy density of sodium, making them more suitable for those portable applications.

Researchers now report a new type of graphene electrode that could boost the storage capacity of sodium batteries to rival lithium's. The material can pack nearly as many sodium ions by volume as a conventional graphite electrode does lithium. It opens up a path to making low-cost, compact sodium batteries practical.

Abundant and cheap, and with similar chemical properties as lithium, sodium is a promising replacement for lithium in next-generation batteries. The stability and safety of sodium batteries makes them especially promising for electronics and cars, where overheated lithium-ion batteries have sometimes proven hazardous.

"But currently the major problem with sodium-ion batteries is that we don't have a suitable anode material," says Jinhua Sun, a researcher in the department of industrial and materials science at Chalmers University of Technology.

For the battery to charge quickly and store a lot of energy, ions need to easily slip in and out of the anode material. Sodium-ion batteries use cathodes made of sodium metal oxides, while their anodes are typically carbon-based anodes just like their lithium cousins; although Santa Clara, California-based Natron Energy is making both its anodes and cathodes out of Prussian Blue pigment used in dyes and paints.

Some sodium battery developers are using activated carbon for the anode, which holds sodium ions in its pores. "But you need to use high-grade activated carbon, which is very expensive and not easy to produce," Sun says....


*We had some hints that the path to usability for graphene might be unusual: