Ionic Conductivity Increased by Two Orders of Magnitude in Micrometer-Thick Vertical Yttria-Stabilized ZrO2 Nanocomposite Films.
We design and create a unique cell geometry of templated micrometer-thick epitaxial nanocomposite films which contain ~20 nm diameter yttria-stabilized ZrO2 (YSZ) nanocolumns, strain coupled to a SrTiO3 matrix. The ionic conductivity of these nanocolumns is enhanced by over 2 orders of magnitude compared to plain YSZ films. Concomitant with the higher ionic conduction is the finding that the YSZ nanocolumns in the films have much higher crystallinity and orientation, compared to plain YSZ films. Hence, "oxygen migration highways" are formed in the desired out-of-plane direction. This improved structure is shown to originate from the epitaxial coupling of the YSZ nanocolumns to the SrTiO3 film matrix and from nucleation of the YSZ nanocolumns on an intermediate nanocomposite base layer of highly aligned Sm-doped CeO2 nanocolumns within the SrTiO3 matrix. This intermediate layer reduces the lattice mismatch between the YSZ nanocolumns and the substrate. Vertical ionic conduction values as high as 10(-2) Ω(-1) cm(-1) were demonstrated at 360 °C (300 °C lower than plain YSZ films), showing the strong practical potential of these nanostructured films for use in much lower operation temperature ionic devices.
Department of Materials Science and Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge, CB3 0FS, United Kingdom.
Shinbuhm
S
Lee
Department of Electrical and Computer Engineering, Texas A&M University , College Station, Texas 77843, United States.
Wenrui
W
Zhang
Department of Electrical and Computer Engineering, Texas A&M University , College Station, Texas 77843, United States.
Fauzia
F
Khatkhatay
Department of Electrical and Computer Engineering, Texas A&M University , College Station, Texas 77843, United States.
Haiyan
H
Wang
Center for Integrated Nanotechnologies, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.
Quanxi
Q
Jia
Department of Materials Science and Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge, CB3 0FS, United Kingdom.
Judith L
JL
MacManus-Driscoll
Ion conductivity; nanocomposite; samarium-doped CeO2; yttria-stabilized ZrO2