TY - JOUR

T1 - Effect of cation substitution in Cs1–2xBaxH2PO4 on structural properties and proton conductivity

AU - Ponomareva, V. G.

AU - Bagryantseva, I. N.

AU - Shutova, E. S.

PY - 2017/7/1

Y1 - 2017/7/1

N2 - We synthesized compounds with partial substitution of Cs+ cations in CsH2PO4 by Ba2+ cations. The structural, electron transport and thermodynamic properties of Cs1–2xBaxH2PO4 (x = 0–0.15) were studied for the first time with the help of a set of physicochemical methods: infrared and impedance spectroscopy, X-ray diffraction and synchronous thermal analysis. The proton conductivity of Cs1–2xBaxH2PO4 at 50–230°C was investigated in detail by impedance measurements. The formation of solid substitution solutions isostructural with CsH2PO4 (P21/m) is observed in the range of substitution degrees of x = 0–0.1, with a slight decrease in the unit cell parameters and some salt amorphization. The conductivity of disordered Cs1–2xBaxH2PO4 in the low-temperature region increases by two orders of magnitude at x = 0.02 and increases with an increasing fraction of barium cations by three or four orders of magnitude at x = 0.05–0.1; the superionic phase transition practically disappears. At x = 0.15, heterophase systems based on salts are formed, showing high conductivity and a further decrease in the activation energy of conductivity to 0.63 eV. The conductivity of the high-temperature phase of Cs1–2xBaxH2PO4 does not change with increasing fraction of the substituent.

AB - We synthesized compounds with partial substitution of Cs+ cations in CsH2PO4 by Ba2+ cations. The structural, electron transport and thermodynamic properties of Cs1–2xBaxH2PO4 (x = 0–0.15) were studied for the first time with the help of a set of physicochemical methods: infrared and impedance spectroscopy, X-ray diffraction and synchronous thermal analysis. The proton conductivity of Cs1–2xBaxH2PO4 at 50–230°C was investigated in detail by impedance measurements. The formation of solid substitution solutions isostructural with CsH2PO4 (P21/m) is observed in the range of substitution degrees of x = 0–0.1, with a slight decrease in the unit cell parameters and some salt amorphization. The conductivity of disordered Cs1–2xBaxH2PO4 in the low-temperature region increases by two orders of magnitude at x = 0.02 and increases with an increasing fraction of barium cations by three or four orders of magnitude at x = 0.05–0.1; the superionic phase transition practically disappears. At x = 0.15, heterophase systems based on salts are formed, showing high conductivity and a further decrease in the activation energy of conductivity to 0.63 eV. The conductivity of the high-temperature phase of Cs1–2xBaxH2PO4 does not change with increasing fraction of the substituent.

KW - FUEL-CELL

KW - SUPERPROTONIC CONDUCTIVITY

KW - BARIUM DIHYDROGENPHOSPHATE

KW - CSH2PO4

KW - COMPOSITES

KW - CS1-XRBXH2PO4

KW - ELECTROLYTES

KW - CONDUCTORS

KW - CRYSTALS

KW - BEHAVIOR

UR - http://www.scopus.com/inward/record.url?scp=85023776695&partnerID=8YFLogxK

U2 - 10.1134/S1063783417070174

DO - 10.1134/S1063783417070174

M3 - Article

AN - SCOPUS:85023776695

VL - 59

SP - 1387

EP - 1394

JO - Physics of the Solid State

JF - Physics of the Solid State

SN - 1063-7834

IS - 7

ER -