Egg-like nanoparticles for lithium-ion batteries. [Image: Zhi Wei She et al., Stanford University]Enlarge Photo
Technology developed at the SLAC National Accelerator Laboratory and Stanford University has set a new record for energy storage in a lithium-ion battery.
Using ingenious egg-like sulfur nanoparticles in the cathode, the battery can store five times more energy than is possible with today's commercial technology--and performance remains high after a thousand charge and discharge cycles.
The technology, says Mike Ross from SLAC (via Cleantechnica) uses a cathode made up of sulfur 'nuggets', surrounded by a shell of porous titanium-oxide. The result superficially resembles the yolk inside a hard eggshell, with an empty space surrounding the sulfur representing the egg white.
Lithium-ion batteries moving lithium ions between the anode and cathode in a battery--into the anode when charging, and into the cathode when discharging.
The more lithium ions you can store, the more energy a battery will store. Sulfur can theoretically store more ions, but has presented a few problems in past experiments. One, a the compound formed by lithium ions bonding with sulfur atoms kept dissolving, and two, its expansion meant that coatings to prevent the dissolving compound would crack and fail.
The egg-like particles, shown clumped together in the image above, solve both issues.
The titanium-oxide shell gives the sulfur enough room to expand--and it's porous, allowing the ions through--but protects the sulfur-lithium compound from dissolving in the electrolyte.
End result: High energy storage without the previous drawbacks.
It also keeps about 70 percent of its energy potential even after 1,000 charging and discharging cycles, even though the design hasn't yet been optimized.
Should the technology reach commercialization, it has all the benefits we've come to expect from improved battery technologies.
It would make the average electric car lighter, since more energy can be stored in a smaller space, and battery life would be improved.
We've heard all that before, but SLAC and Stanford's work is just one more example of how battery tech is progressing behind the scenes. The next few years should be very interesting for the industry...