Skip to main content

PolyPlus Battery Company


Scaleup of Highly Conductive Glass Separators for Next Generation Li Metal Batteries


Founded in 1991, PolyPlus has been at the forefront of the invention and development of next generation battery technologies. With the support of ARPA-E funding, PolyPlus has invented entirely new battery technologies including the water-stable protected lithium electrode (PLE) which was chosen by TIME magazine as one of the best 50 inventions of 2011 and won an Edison Gold Award in 2012. The PLE is also enabling for the PolyPlus lithium-seawater battery which has been classified as critical to US national security and is now being launched commercially. PolyPlus was also the recipient of the largest ARPA-E IONICs award to support the development of its ultra-thin glass separator technology for next generation batteries. Ultra-thin sulfide glass separators are enabling for rechargeable lithium metal electrodes which promise to double the energy density of commercial Li-ion batteries.

Thin-film micro-batteries are the only commercial example of lithium metal cells that can be safely recharged for thousands of cycles without the formation of dendrites. However they are fabricated using inherently slow and costly physical vapor deposition techniques that do not scale at competitive cost and are thereby confined to small niche markets. PolyPlus has invented ultra-thin glass electrolytes that are inherently scaleable at costs which are competitive with commercial polymeric separators and are enabling for high performance rechargeable lithium metal batteries. In its Berkeley, California facility PolyPlus produces high conductivity sulfide glass and then uses proprietary equipment to convert this bulk glass into thin (100 to 400 ┬Ám) sheets for cell testing and external verification. PolyPlus scientists also worked closely with a fiber optics equipment manufacturer to design a one-of-a-kind draw tower to convert sulfide glass pre-forms into continuous 20 micron glass ribbons. This approach is analogous to that used to make ultra-thin glass for the global display markets such as foldable cell phones having thin glass displays. This technology is enabling for rechargeable lithium metal batteries and will lead to a near doubling of energy density relative to commercial Li-ion batteries. PolyPlus glass has an elastic modulus that is more than adequate to block lithium dendrites (~40 GPa), as evidenced by extensive cell testing at its Berkeley California facility. Economic models indicate that glass protected high energy density batteries can achieve cost parity with Li-ion at EV scale, and will yield significant margins in consumer electronic markets where the smaller size and weight of the PolyPlus batteries will allow premium pricing. PolyPlus is currently working with SK Innovation in South Korea, one of the largest electric vehicle battery manufacturers in the world, to commercialize this technology for the global market.

PolyPlus is seeking motivated investors with sufficient financial depth to carry the technology to commercialization, and with the technical knowhow to evaluate the technology and its value in the marketplace. Strategic partners already doing business in the battery field, or motivated to enter the battery field, are particularly interesting. Companies currently manufacturing thin flexible glass for the display markets and/or manufacturing chalcogenide glass optics would also be a good strategic fit.

Contact Information:

Bruce Katz
Manager, Intellectual Property
PolyPlus Battery Company