Structures and electrical properties of core–shell composite electrolytes with multi-heterointerfaces

Thermally and chemically stable phenylsilsesquioxane (PhSiO3/2) particles were prepared by sol–gel process, and ultra-thin layers of oppositely charged poly(diallyldimethylammonium chloride) (PDDA) and dodecatungstophosphoric acid (WPA) were alternately deposited on the negative-charged PhSiO3/2 particles via layer-by-layer assembly technique. Hygroscopic property of WPA was remarkably reduced owing to the formation of PDDA/WPA complex. The amount of WPA adsorbed on PhSiO3/2 particles was estimated to be ∼ 0.03 (g/g PhSiO3/2). Transparent and monolithic pellet can be obtained from the resultant core–shell particles by pressing. Proton conductivity of WPA-deposited samples increased about 4 orders of magnitude compared with unmodified samples, and reached to about 10− 4 S/cm at 80 °C and 80% relative humidity.