Stanford and SLAC National Accelerator Laboratory scientists have used an ingenious yolk-shell design that allows them to store five times more energy in the sulfur cathode of a rechargeable lithium-ion battery than is currently possible with any other commercial technology.
Scientists are optimistic about the design since the cathode had a consistent level of performance even after 1000 charge/discharge cycles, and they are optimistic about future generations of lighter, long-lasting batteries that could be used in electric vehicles and portable electronics. In contrast, current lithium-ion batteries retain only about 80% of their initial capacity after 500 charge/discharge cycles.
To work around previous issues with lithium-ion batteries, scientists created a cathode made of nanoparticles. Each nanoparticle is comprised of a small sulfur nugget surrounded by a shell of porous titanium-oxide; this is not dissimilar to an egg with an egg shell, egg white, and egg yolk in the center.
With the design, lithium ions pass through the shell and bind to the sulfur during the discharging. This fills the void without breaking the shell. Meanwhile, the shell acts as a barrier for the sulfur-lithium compound electrolyte solvent that would otherwise dissolve it.
The Department of Energy (DOE) Office of Basic Energy Sciences has funded the project. The DOE office typically funds high-risk/high-return research that can lead to future innovations.