Mixed alkali effect on thermal and electrochemical properties of MH5(PO4)2/SiP2O7 composite electrolytes at intermediate temperatures

Electrical Behavior and Stability of K2HPO4-KH5(PO4)2-Ce0.9Gd0.1P2O7Composite Electrolytes for Intermediate Temperature Proton-Conducting Fuel Cells

“…8 The comparison of data in Figures 3a-3c implies that the maximum ionic conductivity is generally observed with the K-CGP composites with higher amounts of KH 5 (PO 4 ) 2 , which could be attributed to the presence of highly proton conducting molten KH 5 (PO 4 ) 2 phase in the composite. 19 The ionic conductivity of composites decreases sharply at temperatures >190 • C. The sharp decrease in ionic conductivity of composites beyond 190 • C may be attributed to the dehydration of KH 5 (PO 4 ) 2 phases 12,14,24 as well as due to the phase transition in cerium pyrophosphate phase. 25,26 The graphs in Figures 3d-3f show the dependence of temperature vs. conductivity data on the heat-treatment temperature of a particular composition, which, like the effect of the heat-treatment temperature on the microstructure in Figure 2, give no clear indication about the effect of heat-temperature on the ionic conductivity of the K-CGP composites.…”

“…3,4,11 In order to overcome the abovementioned disadvantages associated with the solid acid phosphates and tetravalent metal phosphates (TMPs), alternative methods of utilizing their high proton conductivity in PCFC electrolytes have been proposed. [12][13][14][15][16][17] A few composite electrolytes of solid acid phosphates have been fabricated with SiO 2 based a materials as supporting matrix. [12][13][14] Similarly, alterz E-mail: song@chonnam.ac.kr native ways to form dense electrolyte substrates of TMPs have been proposed.…”

“…[12][13][14][15][16][17] A few composite electrolytes of solid acid phosphates have been fabricated with SiO 2 based a materials as supporting matrix. [12][13][14] Similarly, alterz E-mail: song@chonnam.ac.kr native ways to form dense electrolyte substrates of TMPs have been proposed. [15][16][17] In this study, we have fabricated composite electrolytes K 2 HPO 4 -KH 5 (PO 4 ) 2 -Ce 0.9 Gd 0.1 P 2 O 7 by combining solid acid phosphates K 2 HPO 4 and KH 5 (PO 4 ) 2 , and a TMP Ce 0.9 Gd 0.1 P 2 O 7 in different ratios.…”

Synthesis, characterization, electrical and dielectric studies of AgCuI and Co-SnO 2 composite solid electrolytes

“…This method was first reported by Liang in 1973 that the LiI-Al 2 O 3 composites have the lithium ion conductivity up to 12 times higher than that of pure LiI [6]. Subsequently, a number of studies such as AgI/X (X = SiO 2 , Al 2 O 3 , TiO 2 ), CsCl/Al 2 O 3 , TlI/X (Al 2 O 3 , TiO 2 ), Li 2 SO 4 / Al 2 O 3 , Na 2 SO 4 /Al 2 O 3 and MH 5 (PO 4 ) 2 /SiP 2 O 7 have been reported by various workers to explain this effect [7][8][9][10][11][12][13][14]. Although a detailed mechanism of these materials has not been clarified, it is considered that thin interfacial layers generated in the heterogeneous system act as the additional source of point defects, resulting the enhancement in ionic conductivity [15][16][17].…”