Stabilization of gamma sulfur enables 4000 cycle Li-S batteries [pdf]
Full title: "Stabilization of gamma sulfur at room temperature to enable the use of carbonate electrolyte in Li-S batteries".  The paper is from February, but it doesn't seem to have been posted before.  TLDR is that with just a new anode made from carbon nanofibers and sulfur, batteries otherwise almost identical to existing Li-Ion batteries would have 2-5 times the energy density, last 3 times as long, and cost 1/3 or less, and be more environmentally benign (not needing cobalt).  The breakthrough here is the discovery that carbon nanofibers stabilize gamma-phase sulfur which previously was thought to only exist briefly at high temperatures, and which doesn't form the polysulfides that have been the main problem with Li-S batteries.<p>Yeah, there have been lots of "breakthrough battery tech" announcements that didn't lead to commercial products, but this one really looks like it may be just the leap forward that will make renewable energy storage a non-problem.