Quantitative demonstration of Al3+ ion conduction in Al2(WO4)3 solids
Abstract Ion conduction of trivalent aluminum in the aluminum tungstate, Al 2 (WO 4 ) 3 , has been quantitatively demonstrated. The ionic conduction characteristics of Al 2 (WO 4 ) 3 were investigated by means of electrolysis and electromotive force (emf) measurement of an aluminum concentration cell by using three types of aluminum–platinum alloys, Al 55 Pt 45 , Al 42 Pt 58 , and Al 35 Pt 65 as the electrodes. The DC electrolysis data strongly support the conclusion that ionic Al 3+ is the mobile species in Al 2 (WO 4 ) 3 . From emf measurements, the mobile species in Al 2 (WO 4 ) 3 was quantitatively identified as aluminum ion in a trivalent state. The conducting properties of the Al 2 (WO 4 ) 3 –In 2 (WO 4 ) 3 solid solution were investigated. The Al 3+ ion conduction increased with the increase of the indium content until 80 mol.% content and the solid solution of 80 mol.% shows five times as high conductivity as pure Al 2 (WO 4 ) 3 . In addition, a macroscopic ionic conduction of trivalent Al 3+ in solids has been directly demonstrated.