MO Ramirez 1, A. Kumar 1, SA Denev 1, NJ Podraza 1, 2, XS Xu 3, RC Rai 3, YH Chu 4, 5, J. Seidel ... more MO Ramirez 1, A. Kumar 1, SA Denev 1, NJ Podraza 1, 2, XS Xu 3, RC Rai 3, YH Chu 4, 5, J. Seidel 4, 5, LW Martin 4, S.-Y. Yang 4, E. Saiz 4, JF Ihlefeld 2, 4, S. Lee 6, J. Klug 7, 8, SW Cheong 6, MJ Bedzyk 7, 8, O. Auciello 8, DG Schlom 1, R. Ramesh 4, 5, J. Orenstein 5, JL ...
Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ioni... more Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La0.8Sr0.2CoO3 (LSC113)and LSC113/LaSrCoO4 (LSC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in LSC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed.
Low-symmetry monoclinic phases in ferroelectric materials are of considerable interest, due to th... more Low-symmetry monoclinic phases in ferroelectric materials are of considerable interest, due to their associated enhanced electromechanical coupling. Such phases have been found in Pb-based perovskite solid solutions such as lead zirconate titanate (PZT), where they ...
Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fue... more Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fuel cells (SOFC) and Li-air batteries are one of integral components of current and future energy technologies. The energy conversion in these systems is underpinned by a series of complex mechanisms like ion and vacancy diffusion, electronic transport and solid-gas and solidliquid reactions at surfaces and triple phase junctions. One of the critical steps in the SOFC and Li-air battery operation leading to large overpotentials and ...
Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fue... more Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fuel cells (SOFC) are one of integral components of current and future energy technologies. The energy conversion in these systems is underpinned by a series of complex mechanisms like ion and vacancy diffusion, electronic transport and solid-gas and solid-liquid reactions at surfaces and triple phase junctions. One of the critical steps in the SOFC and Li-air battery operation leading to large overpotentials and charge-discharge ...
ABSTRACT Scanning probe microscopy methods have been used to electrodeposit and cycle micron-scal... more ABSTRACT Scanning probe microscopy methods have been used to electrodeposit and cycle micron-scale Li anodes deposited electrochemically under nanofabricated Au current collectors. An average Li volume of 5 x 10(8) nm(3) was deposited and cycled with 100% coulombic efficiency for similar to 160 cycles. Integrated charge/discharge values agree with before/after topography, as well as in situ dilatometry, suggesting this is a reliable method to study solid-state electrochemical processes. In this work we illustrate the possibility to deposit highly cyclable nanometer thick Li electrodes by mature SPM and nanofab techniques which can pave the way for inexpensive nanoscale battery arrays.
Static domain structures and polarization dynamics of silicon doped HfO2 are explored. The evolut... more Static domain structures and polarization dynamics of silicon doped HfO2 are explored. The evolution of ferroelectricity as a function of Si-doping level driving the transition from paraelectricity via ferroelectricity to antiferroelectricity is investigated. Ferroelectric and antiferroelectric properties can be observed locally on the pristine, poled and electroded surfaces, providing conclusive evidence to intrinsic ferroic behavior.
MO Ramirez 1, A. Kumar 1, SA Denev 1, NJ Podraza 1, 2, XS Xu 3, RC Rai 3, YH Chu 4, 5, J. Seidel ... more MO Ramirez 1, A. Kumar 1, SA Denev 1, NJ Podraza 1, 2, XS Xu 3, RC Rai 3, YH Chu 4, 5, J. Seidel 4, 5, LW Martin 4, S.-Y. Yang 4, E. Saiz 4, JF Ihlefeld 2, 4, S. Lee 6, J. Klug 7, 8, SW Cheong 6, MJ Bedzyk 7, 8, O. Auciello 8, DG Schlom 1, R. Ramesh 4, 5, J. Orenstein 5, JL ...
Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ioni... more Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La0.8Sr0.2CoO3 (LSC113)and LSC113/LaSrCoO4 (LSC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in LSC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed.
Low-symmetry monoclinic phases in ferroelectric materials are of considerable interest, due to th... more Low-symmetry monoclinic phases in ferroelectric materials are of considerable interest, due to their associated enhanced electromechanical coupling. Such phases have been found in Pb-based perovskite solid solutions such as lead zirconate titanate (PZT), where they ...
Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fue... more Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fuel cells (SOFC) and Li-air batteries are one of integral components of current and future energy technologies. The energy conversion in these systems is underpinned by a series of complex mechanisms like ion and vacancy diffusion, electronic transport and solid-gas and solidliquid reactions at surfaces and triple phase junctions. One of the critical steps in the SOFC and Li-air battery operation leading to large overpotentials and ...
Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fue... more Electrochemical energy conversion systems based on gas-solid interactions such as solid oxide fuel cells (SOFC) are one of integral components of current and future energy technologies. The energy conversion in these systems is underpinned by a series of complex mechanisms like ion and vacancy diffusion, electronic transport and solid-gas and solid-liquid reactions at surfaces and triple phase junctions. One of the critical steps in the SOFC and Li-air battery operation leading to large overpotentials and charge-discharge ...
ABSTRACT Scanning probe microscopy methods have been used to electrodeposit and cycle micron-scal... more ABSTRACT Scanning probe microscopy methods have been used to electrodeposit and cycle micron-scale Li anodes deposited electrochemically under nanofabricated Au current collectors. An average Li volume of 5 x 10(8) nm(3) was deposited and cycled with 100% coulombic efficiency for similar to 160 cycles. Integrated charge/discharge values agree with before/after topography, as well as in situ dilatometry, suggesting this is a reliable method to study solid-state electrochemical processes. In this work we illustrate the possibility to deposit highly cyclable nanometer thick Li electrodes by mature SPM and nanofab techniques which can pave the way for inexpensive nanoscale battery arrays.
Static domain structures and polarization dynamics of silicon doped HfO2 are explored. The evolut... more Static domain structures and polarization dynamics of silicon doped HfO2 are explored. The evolution of ferroelectricity as a function of Si-doping level driving the transition from paraelectricity via ferroelectricity to antiferroelectricity is investigated. Ferroelectric and antiferroelectric properties can be observed locally on the pristine, poled and electroded surfaces, providing conclusive evidence to intrinsic ferroic behavior.
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