Synthesis of Hyper-branched PEO Silica Nanoparticles for Solid Polymer Electrolytes of Lithium Ion Battery

Abstract

Hyper-branched silica nanoparticles were blended with PEO (20.0 kDa) for inorganic composite solid polymer electrolytes. In this research work, to study the effect of ionic conductivity on the molecular weight of hyper-branched polymer, hyper-branched polyglycidol of 5th, 6th and 7th generation were synthesized by cationic ring opening polymerization. Solid electrolyte, which is silica nanoparticle with nitrile group modified 6th generation hyper-branched polyglycidol blended with 1:1 wt% PEO, has maximum ionic conductivity of 8.4 x 10-5 S/cm at 30oC. It has higher ionic conductivity than PEO in the temperature range from 30 oC to 80 oC. The ionic conductivity of these inorganic composite solid polymer electrolytes is correlated to the inhibition of crystallization of PEO by well distributed nanoparticles and the formation of ion path by phase separation of silica nanoparticle as the hard segment and PEO as the soft segment.