Inorganic—organic copolymers as solid state Li+ electrolytes

Inorganic—organic copolymers (ORMOCERs = ORganically MOdified CERamics), which are synthesized by sol—gel processing, were developed as host materials for lithium salts. They consist of an inorganic oxidic backbone (Si, Zr, etc) chemically bonded to an organic network, eg by use of functionalized organosilanes, and are prepared by polycondensation (to form the inorganic oxidic network) in combination with organic crosslinking reactions. Dissolution of controlled amounts of LiClO4, in the ORMOCER-containing grafted polyethylene oxide leads to an electrolyte. The material is amorphous according to X-ray diffraction patterns. It has an ion conductivity of σ = 10−5 Ω−1 cm−1 at room temperature and σ = 10−3 Ω−1 cm−1 at 125°C. The material can be applied as coating or bulk by standard technologies and shows good adhesion to various substrate materials. Final curing can be initiated by uv-light and/or thermal treatment.