Temperature dependent ionic transport properties in composite solid polymer electrolytes

In the present work, temperature dependent lithium transference number TLi+ of poly (ethylene oxide)/LiClO4 composite solid polymer electrolytes containing mesoporous silica SBA-15 was studied. TLi+ reaches a low value around the melting point (Tm) of the polymer electrolyte and increases as temperature deviates from Tm, which is due to the different mechanisms of lithium conduction and anion conduction. While the anion transport mainly involves hopping between free volumes large enough to accommodate the ions, lithium ions are transferred by making and breaking of bonds with motion between coordinating sites. In comparison with the polymer electrolyte without SBA-15, the composite polymer electrolytes containing SBA-15 exhibit higher values of TLi+ and lithium conductivity.