Proton conductors based on ammonium polyphosphate

Stability and conductivity study of NH4PO3–PTFE composites at intermediate temperatures

“…Recently, ammonium polyphosphate (APP, NH 4 PO 3 ) has been studied as a intermediate-temperature proton conducting electrolyte [8][9][10][11][12][13]. However, pure phase APP is not stable at the temperature of more than 250 • C. Considerable efforts have recently been devoted to the application of supporting matrix, which can enhance its stability, mechanic strength and ionic conductivity.…”

Proton-Conductive Electrolyte Consisting of NH[sub 4]PO[sub 3]/TiP[sub 2]O[sub 7] for Intermediate-Temperature Fuel Cells

“…Therefore, highly ion-conductive electrolytes at intermediate temperature regions are required to develop intermediatetemperature fuel cells, although only a few studies have been conducted on electrolytes for use at 250-600°C. [5][6][7][8] Recently, an ammonium polyphosphate composite, NH 4 PO 3 /(NH 4 ) 2 SiP 4 O 13 , was reported to exhibit conductivities of 20 and 100 mS cm Ϫ1 at 300°C under dry and wet atmospheres, respectively.9 In this composite, NH 4 PO 3 is responsible for high ionic conductivity in a supporting matrix of (NH 4 ) 2 SiP 4 O 13 .8 The high ionic conductivity originates in the partial decomposition of NH 4 PO 3 to HPO 3 at around 250°C. Accordingly, the supporting matrix has to be stable and should contribute to ion conduction.…”

“…9 In this composite, NH 4 PO 3 is responsible for high ionic conductivity in a supporting matrix of (NH 4 ) 2 SiP 4 O 13 . 8 The high ionic conductivity originates in the partial decomposition of NH 4 PO 3 to HPO 3 at around 250°C. Accordingly, the supporting matrix has to be stable and should contribute to ion conduction.…”

Compound of (NH4)2SnP4O13 with high proton conductivity in both dry and humid atmospheres as electrolyte for intermediate temperature fuel cells

“…Recently, studies on conductivity, thermal and mechanical stability of ammonium phosphate showed that the partial decomposition of NH 4 PO 3 to HPO 3 , with concomitant release of NH 3 , may be responsible for the relatively high conductivity that this material exhibits in dry atmosphere [5]. Moreover, as shown later, higher conductivities can be obtained in the presence of water [6].…”