TY - JOUR
T1 - Proton-conducting phosphate glass and its melt exhibiting high electrical conductivity at intermediate temperatures
AU - Yamaguchi, Takuya
AU - Tsukuda, Satoshi
AU - Ishiyama, Tomohiro
AU - Nishii, Junji
AU - Yamashita, Toshiharu
AU - Kawazoe, Hiroshi
AU - Omata, Takahisa
N1 - Funding Information:
This work was supported in part by the Advanced Low Carbon Technology Research and Developing Program of the Japan Science and Technology Agency (JST-ALCA), a Grant-in-Aid for Scientic Research of Challenging Exploratory Research (Grant No. 15K14126), and a Grant-in-Aid for the Japan Society for the Promotion of Science (JSPS) Fellows (Grant No. 17J07530). This work was partly performed under the Cooperative Research Program of the “Network Joint Research Center for Materials and Devices” (No. 20163006, 20173019, and 20183028) and “Dynamic Alliance for Open Innovation Bridging Human, Environment, and Materials”.
Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2018
Y1 - 2018
N2 - A working hypothesis to design proton-conducting phosphate glasses exhibiting high proton conductivity and high stability was proposed. In this hypothesis, the precursor glass before electrochemical alkali-proton substitution (APS) is required to fulfill the terms of (i) the concentration of NaO1/2 in the precursor glass needs to be higher than 35 mol%, (ii) the O/P ratio of the glass composition cannot exceed 3.5, (iii) the glass network modifier oxides need to consist of cations with low electronegativity, (iv) the glass must contain a sufficient amount of glass network modifiers and intermediate oxides, such as alkaline-earth oxides, Al2O3, Y2O3, La2O3, WO3, Nb2O5, and Ta2O5, (v) the glass needs to consist of more than four or five components, and (vi) the glass must contain a small amount of GeO2 and/or B2O3. Based on the proposed working hypothesis, we obtained a 36HO1/2-4NbO5/2-2BaO-4LaO3/2-4GeO2-1BO3/2-49PO5/2 glass (36H-glass) by APS. While the glass transition temperature of 36H-glass was 179 °C, the glass, accurately the super cooled liquid, was stable for a long time up to 280 °C under fuel cell operating conditions and exhibited 1 × 10−3 S cm−1 at 280 °C, indicating that the developed working hypothesis is useful to design new proton-conducting electrolytes that work at intermediate temperatures.
AB - A working hypothesis to design proton-conducting phosphate glasses exhibiting high proton conductivity and high stability was proposed. In this hypothesis, the precursor glass before electrochemical alkali-proton substitution (APS) is required to fulfill the terms of (i) the concentration of NaO1/2 in the precursor glass needs to be higher than 35 mol%, (ii) the O/P ratio of the glass composition cannot exceed 3.5, (iii) the glass network modifier oxides need to consist of cations with low electronegativity, (iv) the glass must contain a sufficient amount of glass network modifiers and intermediate oxides, such as alkaline-earth oxides, Al2O3, Y2O3, La2O3, WO3, Nb2O5, and Ta2O5, (v) the glass needs to consist of more than four or five components, and (vi) the glass must contain a small amount of GeO2 and/or B2O3. Based on the proposed working hypothesis, we obtained a 36HO1/2-4NbO5/2-2BaO-4LaO3/2-4GeO2-1BO3/2-49PO5/2 glass (36H-glass) by APS. While the glass transition temperature of 36H-glass was 179 °C, the glass, accurately the super cooled liquid, was stable for a long time up to 280 °C under fuel cell operating conditions and exhibited 1 × 10−3 S cm−1 at 280 °C, indicating that the developed working hypothesis is useful to design new proton-conducting electrolytes that work at intermediate temperatures.
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U2 - 10.1039/C8TA08162J
DO - 10.1039/C8TA08162J
M3 - Article
AN - SCOPUS:85057524892
SN - 2050-7488
VL - 6
SP - 23628
EP - 23637
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 46
ER -
