Solid electrolytes and photoelectrolysis

Three classes of cubic skeleton structures were explored for fast Na ion transport for use as solid electrolytes in Na-S batteries. The cubic KSbO3 structure consists of an SbO3(-) skeleton having (III) tunnels intersecting at origin and body-center positions. NaSbO3 and NaSbO3-(1/6)NaF disks of about 95 percent theoretical density give a Na ion resistivity at 300 C approximately equal to 13 ohm-cm and an activation energy of approximately 0.35 eV. Preliminary investigations of aluminosilicates having the carnegieite structure show promise, but a resistivity approximately equal to 610 ohm-cm is the best that was achieved. The use of inexpensive, n-type hot pressed TiO2 powders as the working photocatalytic electrode for achieving photoelectrolysis of water was investigated. A study of the physics and electrochemistry of a photoelectrolysis cell consisting of TiO2 as the anode and platinized platinum as the cathode led to an optimization of the parameters of the system.