Research output: Contribution to journal › Article › peer-review
Proton Conductivity and Thermal Properties of Ba(H2PO4)2. / Bagryantseva, I. N.; Ponomareva, V. G.
In: Inorganic Materials, Vol. 54, No. 4, 01.04.2018, p. 366-373.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Proton Conductivity and Thermal Properties of Ba(H2PO4)2
AU - Bagryantseva, I. N.
AU - Ponomareva, V. G.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - We have grown single crystals of barium dihydrogen phosphate and studied its thermal transformations during heating to 500°C and its electrotransport properties. Ba(H2PO4)2 (Pccn) has been shown to undergo no phase transitions up to its dehydration temperature. The thermal decomposition of Ba(H2PO4)2, accompanied by dehydration, involves two steps, with maximum rates at ~265 and 370°C, and results in the formation of barium dihydrogen pyrophosphate and barium metaphosphate, respectively. The total enthalpy of the endothermic dehydration events is–244.6 J/g. Using impedance spectroscopy, we have studied in detail the proton conductivity of polycrystalline and single-crystal Ba(H2PO4)2 samples in a controlled atmosphere. Adsorbed water has been shown to have a significant effect on the proton conductivity of Ba(H2PO4)2 up to 130°C. The proton conductivity of the Ba(H2PO4)2 single crystals has been shown to be anisotropic. The conductivity anisotropy correlates with specific structural features of the salt. Higher conductivity values, 3 × 10–9 to 2 × 10–7 S/cm in the range 60–160°C, have been observed in the [100] crystallographic direction, exceeding the conductivity along [010] by an order of magnitude. The activation energy for proton conduction is 0.80 eV.
AB - We have grown single crystals of barium dihydrogen phosphate and studied its thermal transformations during heating to 500°C and its electrotransport properties. Ba(H2PO4)2 (Pccn) has been shown to undergo no phase transitions up to its dehydration temperature. The thermal decomposition of Ba(H2PO4)2, accompanied by dehydration, involves two steps, with maximum rates at ~265 and 370°C, and results in the formation of barium dihydrogen pyrophosphate and barium metaphosphate, respectively. The total enthalpy of the endothermic dehydration events is–244.6 J/g. Using impedance spectroscopy, we have studied in detail the proton conductivity of polycrystalline and single-crystal Ba(H2PO4)2 samples in a controlled atmosphere. Adsorbed water has been shown to have a significant effect on the proton conductivity of Ba(H2PO4)2 up to 130°C. The proton conductivity of the Ba(H2PO4)2 single crystals has been shown to be anisotropic. The conductivity anisotropy correlates with specific structural features of the salt. Higher conductivity values, 3 × 10–9 to 2 × 10–7 S/cm in the range 60–160°C, have been observed in the [100] crystallographic direction, exceeding the conductivity along [010] by an order of magnitude. The activation energy for proton conduction is 0.80 eV.
KW - barium dihydrogen phosphate
KW - proton conductivity
KW - thermal properties
KW - PHOSPHATE
KW - PHASES
KW - CRYSTAL-STRUCTURE
KW - INTERCALATION
UR - http://www.scopus.com/inward/record.url?scp=85045725791&partnerID=8YFLogxK
U2 - 10.1134/S0020168518040027
DO - 10.1134/S0020168518040027
M3 - Article
AN - SCOPUS:85045725791
VL - 54
SP - 366
EP - 373
JO - Inorganic Materials
JF - Inorganic Materials
SN - 0020-1685
IS - 4
ER -
ID: 12799213