TY - JOUR
T1 - Ion-conducting, sub-100 nm-thick film of amorphous hafnium silicate
AU - Aoki, Yoshitak
AU - Habazaki, Hiroki
AU - Kunitake, Toyoki
N1 - Funding Information:
We thank to the assistance by Dr. A. Nakao of Surface Analysis Lab., RIKEN in XPS measurements. The authors are also grateful to E. Muto for technical support of TEM experiments. This work was financially supported by the Grant-in-Aid of JSPS for Scientific Research on Young Scientists (B) and by the Global COE Program (Project No. B01: Catalysis as the Basis for Innovation in Materials Science) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
PY - 2010/2/24
Y1 - 2010/2/24
N2 - Ceramic electrolytes operating in the temperature range of 200 to 500 °C under dry atmosphere are a key material for the next-generation fuel cell and related applications. We discovered that nanometer-thick films of amorphous hafnium silicate (HfnSi1 - nOx) exhibited efficient ionic conduction at 100-400 °C in dry air. When the fraction of hafnium doping was around 0.1, the nanofilm showed a low area-specific-resistance (< 0.15 Ω cm2) at around 350 °C that was small enough for the practical fuel cell application. The sub-100 nm-thick membranes of Hf0.13Si0.87Ox, could be fabricated on porous Pt/alumina substrate to provide gas concentration cells. The electromotive force observed with H2 concentration cell indicated that the ceramic nanomembrane acted as predominant proton conductor without permeation of H2 gas. In addition, the Hf0.13Si0.87Ox and Zr0.11Si0.89Ox membranes responded to the change of O2 pressures in O2 concentration cells, while the Al0.16Si0.84Ox and Ce0.06Si0.94Ox membranes did not produce the electrical voltage by gradient of O2 pressure. We conclude that Hf0.13Si0.87Ox nanomembrane is promising as electrolyte material for fuel cells and related ionics devices.
AB - Ceramic electrolytes operating in the temperature range of 200 to 500 °C under dry atmosphere are a key material for the next-generation fuel cell and related applications. We discovered that nanometer-thick films of amorphous hafnium silicate (HfnSi1 - nOx) exhibited efficient ionic conduction at 100-400 °C in dry air. When the fraction of hafnium doping was around 0.1, the nanofilm showed a low area-specific-resistance (< 0.15 Ω cm2) at around 350 °C that was small enough for the practical fuel cell application. The sub-100 nm-thick membranes of Hf0.13Si0.87Ox, could be fabricated on porous Pt/alumina substrate to provide gas concentration cells. The electromotive force observed with H2 concentration cell indicated that the ceramic nanomembrane acted as predominant proton conductor without permeation of H2 gas. In addition, the Hf0.13Si0.87Ox and Zr0.11Si0.89Ox membranes responded to the change of O2 pressures in O2 concentration cells, while the Al0.16Si0.84Ox and Ce0.06Si0.94Ox membranes did not produce the electrical voltage by gradient of O2 pressure. We conclude that Hf0.13Si0.87Ox nanomembrane is promising as electrolyte material for fuel cells and related ionics devices.
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U2 - 10.1016/j.ssi.2009.02.016
DO - 10.1016/j.ssi.2009.02.016
M3 - Article
AN - SCOPUS:77649188422
VL - 181
SP - 115
EP - 121
JO - Solid State Ionics
JF - Solid State Ionics
SN - 0167-2738
IS - 3-4
ER -