Month: July 2017

Enlarge / Some lithium metal. Note the surface has already reacted with something. (credit: Wikimedia Commons)

Lithium ions, as the name implies, work by shuffling lithium atoms between a battery's two electrodes. So, increasing a battery's capacity is largely about finding ways to put more lithium into those electrodes. These efforts, however, have run into significant problems. If lithium is a large fraction of your electrode material, then moving it out can cause the electrode to shrink. Moving it back in can lead to lithium deposits in the wrong places, shorting out the battery.

Now, a research team from Stanford has figured out how to wrap lots of lithium in graphene. The resulting structure holds a place open for lithium when it leaves, allowing it to flow back to where it started. Tests of the resulting material, which they call a lithium-graphene foil, show it could enable batteries with close to twice the energy density of existing lithium batteries.

Lithium behaving badly

One obvious solution to increasing the amount of lithium in an electrode is simply to use lithium metal itself. But that's not the easiest thing to do. Lithium metal is less reactive than the other members of its column of the periodic table (I'm looking at you, sodium and potassium), but it still reacts with air, water, and many electrolyte materials. In addition, when lithium leaves the electrode and returns, there's no way to control where it re-forms metal. After a few charge/discharge cycles, the lithium electrode starts to form sharp spikes that can ultimately grow large enough to short out the battery.

Moon Express

After several years of secrecy, a company called Moon Express revealed the scope of its ambitions on Wednesday. And they are considerable. The privately held company released plans for a single, modular spacecraft that can be combined to form successfully larger and more capable vehicles. Ultimately the company plans to establish a lunar outpost in 2020 and set up commercial operations on the Moon.

Perhaps most intriguingly, Moon Express says it is self-funded to begin bringing kilograms of lunar rocks back to Earth within about three years. “We absolutely intend to make these samples available globally for scientific research, and make them available to collectors as well,” said Bob Richards, one of the company’s founders, in an interview with Ars.