Polyethylene Glycol Functionalized Polyoctahedral Silsesquioxanes as Electrolytes for Lithium Batteries

The conductivity of polyoctahedral silsesquioxanes [POSS-PEO ]-based electrolytes has been investigated as a function of ratio for , , , , , , and . increased with increasing salt concentration and poly(ethylene oxide) chain length . At high temperatures, , corresponding to low-viscosity conditions, conductivity increased with increasing salt concentration and the conductivities of the less-associative salts [, , , , and ] were greater than those of the more associative salts [ and ] due to increased numbers of charge carriers. At low temperatures, , corresponding to high-viscosity conditions, the salts [, , , and ] with lower had higher conductivities than the higher salts [, , and ] due to increased mobility of the ethylene oxide units. Decreased resulted from: (i) plasticization effects of the large, flexible and anions and (ii) decreased complexation for the associative and salts. The flexible, bulky anion decreased the crystallinity of semicrystalline POSS more than the smaller . acted like an inert filler. The highest conductivity, , was obtained for POSS- .