Founded in 1990, PolyPlus began operations in 1991, based on work previously done at Lawrence Berkeley National Laboratory on lithium/organosulfur (Li-S) batteries. The Li-S technology is now mature, has been licensed for production, and is a commercial product. Development of the company’s signature Protected Lithium Electrode (PLE) began during their work on Li-S batteries, but has proven more broadly applicable. PLEs are metallic lithium encapsulated within
a solid electrolyte membrane to prevent direct electron transfer from the negative electrode to the (fluid) electrolyte (whether polysulfide, water, or air).
The solid electrolyte is highly conductive to lithium ions, but impervious to liquids and gases. In this way, the lithium core is electrochemically active but chemically isolated from the external electrolyte. The result is batteries with unusually high energy densities, several times higher than Li-ion. PolyPlus is currently developing both Lithium-Water and Lithium-Air batteries, and hopes to take the Lithium-Water variant to market next year. Li-Water batteries are expected to quickly find their way into buoys and other aquatic devices, including unmanned submersibles. The company has received a grant from ARPA-E for the development of rechargeable Li-Air batteries. Its Li-Water technology was included among Time Magazines 50 Best Inventions for 2011, and more recently it received the 2012 Gold Edison Award in Energy and Sustainability for its work in Li-Air and Li-Water batteries.