New Process of Solidification under Low Temperature of Cation Conductive NaSn2(PO4)3 Synthesized Hydrothermally

Abstract

Abstract NaSn2(PO4)3 hard bulk materials were successfully obtained by low-temperature calcination (~600 °C) from hydrothermally synthesized sols without a powder-press or sintering at high temperature. A hydrothermal reaction was performed at 250 °C for 5 h using an aqueous solution of NaOH, an aqueous solution of SnCl4, and H3PO4 as starting materials. The ratio of the starting materials was changed, and the range in which NaSn2(PO4)3 was formed was investigated. As a result, the sample hydrothermally synthesized under the synthesis conditions of Na: Sn: P = 2.75: 0.50: 1.75 was produced as a white sol in a Teflon container. In order to remove Cl from this sol, an immersion treatment with deionized water was performed. After immersion treatment for 3 h, and calcination at 600-900 °C, it was possible to obtain the target substance NaSn2(PO4)3 as a hard bulk material.