A new highly conductive organic-inorganic solid polymer electrolyte based on a di-ureasil matrix doped with lithium perchlorate

摘要

A new hybrid organic-inorganic polymer electrolyte based on poly(propylene glycol) tolylene 2,4-diisocyanate terminated (PPGTDI), poly(propylene glycol)-block-poly(ethylene glycol)-block-poly-(propylene glycol) bis(2-aminopropyl ether) (ED2000) and 3-isocyanatepropyltriethoxysilane (ICPTES) has been synthesized and characterized. A maximum ionic conductivity value of 1.0 x 10~(-4) S cm~(-1) at 30 °C and 1.1 x 10~(-3) S cm~(-1) at 80 °C is achieved for the hybrid electrolyte with a [O]/[Li] ratio of 32. The conductivity mechanism changes from Arrhenius to Vogel-Tamman-Fulcher (VTF) behavior with the increase in temperature from 20 to 80 °C. The present hybrid electrolyte system offers a remarkable improvement in ionic conductivity by at least one order of magnitude higher than the previously reported organic-inorganic electrolytes. The ~7Li NMR (nuclear magnetic resonance) results reveal that there exists a strong correlation between the dynamic properties of the charge carriers and the polymer matrix. Two Li~+ local environments are identified, for the first time, in such a di-ureasil based polymer electrolyte. The electrochemical stability window is found to be in the range of 4.6-5.0 V, which ensures that the present hybrid electrolyte is a potential polymer electrolyte for solid-state rechargeable lithium ion batteries.