OXIS is the first company to commercialize lithium sulfur batteries. OXIS has been achieving 20-percent year-over-year improvements for cells that are presently delivering 200 Wh/kg at the pouch cell level, 350 Wh/kg at the coin cell level, and with promise of a doubling or more in the next 2-3 years.
Li-S battery manufacturing can use existing, excess battery manufacturing facilities with minimal modifications. Li-S batteries could scale to over batteries for over 100,000 electric vehicles and get costs down to $65/kwh.
This is not a whole lot better than li-ion, but Li-S offers other benefits not least of which is major upside potential.
The theoretical energy density of lithium-sulfur is actually 2,700 Wh/kg, or five times that of lithium-ion.
IBM has said lithium-air will be practical some time in the early 2020s – how it can have 2020 vision a decade into the future is a good critical question, but we digress. In any case, OXIS’ statements are of what it has in its hands now. OXIS does concede Li-Air is the next step beyond Li-S, but Crittenden says he doesn’t think Li-Air will be ready until after 2030.
Despite the U.S. government demanding more for Li-S before using it for electric car batteries, other government entities – particularly the military – see reason to get started now.
Crittenden says energy storage systems using metallic lithium offer the highest specific energy, and OXIS has also received support for UK Ministry of Defense battery packs to be carried by NATO soldiers. Soldiers must carry 8 kg or so, and if this can be cut in half, that is a huge tactical advantage in the eyes of commanders.
The first cars to receive Li-S batteries appear to be the INDUCT Modulgo Urban Car and driverless Navia.
The Navia will get an approximately 10-kilowatt-hour Li-S pack in 2014. Two wheelers to receive OXIS batteries will be the WESP scooter, which is made by QWIC of the Netherlands, and to be distributed to around 350 shops in the Netherlands, Belgium, Germany and France. Whisper e-bikes will also get Li-S batteries.
PolyPlus’s Li-water battery has been clocked at 1,300 Wh/kg – well above the 400-450 Wh/kg theoretical limit of Li-ion batteries – and Visco believes they will reach an energy density of 1,500 Wh/kg by the time the technology is commercialized in 2013. Still, that is just the tip of the iceberg that could bring down the titanic combustion engine when PolyPlus batteries finally reach the EV market in as many as 10 years. PolyPlus has calculated the theoretical energy density of its Li-air technology at 11,000 Wh/kg.
Lithium-sulfur based battery prototypes using NOHMs materials have demonstrated more than 400 Wh/kg and more than 500 recharges using gram-scale materials synthesis; more than 3 times the energy density of commercially available lithium-ion batteries; and using materials and processes that have the potential to make batteries at 1/3 of the manufactured cost.
Recommended path for Li-S batteries