Phase segregation and miscibility of TiOxnanocomposites in Gd-doped ceria solid electrolyte material

Junying Li; Prahlad K. Routh; Yuanyuan Li; Anna Plonka; Evgeniy Makagon; Igor Lubomirsky; Anatoly Frenkel

doi:10.1107/S1600577523003636

Phase segregation and miscibility of TiO_xnanocomposites in Gd-doped ceria solid electrolyte material

Junying Li, Prahlad K. Routh, Yuanyuan Li, Anna Plonka, Evgeniy Makagon, Igor Lubomirsky, Anatoly Frenkel

Research output: Contribution to journal › Article › peer-review

Abstract

Electro-chemo-mechanical (ECM) coupling refers to mechanical deformation due to electrochemically driven compositional change in a solid. An ECM actuator producing micrometre-size displacements and long-term stability at room temperature was recently reported, comprising a 20 mol% Gd-doped ceria (20GDC), a solid electrolyte membrane, placed between two working bodies made of TiO x /20GDC (Ti-GDC) nanocomposites with Ti concentration of 38 mol%. The volumetric changes originating from oxidation or reduction in the local TiO x units are hypothesized to be the origin of mechanical deformation in the ECM actuator. Studying the Ti concentration-dependent structural changes in the Ti-GDC nanocomposites is therefore required for (i) understanding the mechanism of dimensional changes in the ECM actuator and (ii) maximizing the ECM response. Here, the systematic investigation of the local structure of the Ti and Ce ions in Ti-GDC over a broad range of Ti concentrations using synchrotron X-ray absorption spectroscopy and X-ray diffraction is reported. The main finding is that, depending on the Ti concentration, Ti atoms either form a cerium titanate or segregate into a TiO2 anatase-like phase. The transition region between these two regimes with Ti(IV) concentration between 19% and 57% contained strongly disordered TiO x units dispersed in 20GDC containing Ce(III) and Ce(IV) and hence rich with oxygen vacancies. As a result, this transition region is proposed to be the most advantageous for developing ECM-active materials.

Original language	English
Pages (from-to)	758-765
Number of pages	8
Journal	Journal of Synchrotron Radiation
Volume	30
DOIs	https://doi.org/10.1107/S1600577523003636
State	Published - May 26 2023
Externally published	Yes

Funding

This research used beamlines 8-BM and 28-ID-2 of the National Synchrotron Light Source II (NSLS-II), a US DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract No. DE-SC0012704. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. We gratefully acknowledge Dr Yonghua Du for his support of these experiments at the 8-BM beamline, Dr Sanjit Ghose for his support of these experiments at the 28-ID-2 beamline of NSLS-II, and Dr Erik Nelson for his support at the 4-3 beamline of SSRL. We acknowledge support by the Synchrotron Catalysis Consortium funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Grant No. DE-SC0012335. AIF acknowledges support by Weston Visiting Professorship during his stay at the Weizmann Institute of Science. The following funding is acknowledged: National Science Foundation (grant No. DMR-1911592 to Anatoly Frenkel, Junying Li, Yuanyuan Li, Prahlad K. Routh); Binational Science Foundation (Israel) (grant No. 2018717 to Igor Lubomirsky).

Funders	Funder number
Synchrotron Catalysis Consortium	DE-SC0012335
National Science Foundation	DMR-1911592
U.S. Department of Energy
Office of Science
Basic Energy Sciences	DE-AC02-76SF00515
Brookhaven National Laboratory	DE-SC0012704
United States-Israel Binational Science Foundation	2018717

Keywords

X-ray absorption spectroscopy
electro-chemo-mechanical effect
local structural disorder

Access to Document

10.1107/S1600577523003636

Cite this

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title = "Phase segregation and miscibility of TiOxnanocomposites in Gd-doped ceria solid electrolyte material",

abstract = "Electro-chemo-mechanical (ECM) coupling refers to mechanical deformation due to electrochemically driven compositional change in a solid. An ECM actuator producing micrometre-size displacements and long-term stability at room temperature was recently reported, comprising a 20 mol% Gd-doped ceria (20GDC), a solid electrolyte membrane, placed between two working bodies made of TiO x /20GDC (Ti-GDC) nanocomposites with Ti concentration of 38 mol%. The volumetric changes originating from oxidation or reduction in the local TiO x units are hypothesized to be the origin of mechanical deformation in the ECM actuator. Studying the Ti concentration-dependent structural changes in the Ti-GDC nanocomposites is therefore required for (i) understanding the mechanism of dimensional changes in the ECM actuator and (ii) maximizing the ECM response. Here, the systematic investigation of the local structure of the Ti and Ce ions in Ti-GDC over a broad range of Ti concentrations using synchrotron X-ray absorption spectroscopy and X-ray diffraction is reported. The main finding is that, depending on the Ti concentration, Ti atoms either form a cerium titanate or segregate into a TiO2 anatase-like phase. The transition region between these two regimes with Ti(IV) concentration between 19% and 57% contained strongly disordered TiO x units dispersed in 20GDC containing Ce(III) and Ce(IV) and hence rich with oxygen vacancies. As a result, this transition region is proposed to be the most advantageous for developing ECM-active materials.",

keywords = "X-ray absorption spectroscopy, electro-chemo-mechanical effect, local structural disorder",

author = "Junying Li and Routh, {Prahlad K.} and Yuanyuan Li and Anna Plonka and Evgeniy Makagon and Igor Lubomirsky and Anatoly Frenkel",

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T1 - Phase segregation and miscibility of TiOxnanocomposites in Gd-doped ceria solid electrolyte material

AU - Li, Junying

AU - Routh, Prahlad K.

AU - Li, Yuanyuan

AU - Plonka, Anna

AU - Makagon, Evgeniy

AU - Lubomirsky, Igor

AU - Frenkel, Anatoly

PY - 2023/5/26

Y1 - 2023/5/26

N2 - Electro-chemo-mechanical (ECM) coupling refers to mechanical deformation due to electrochemically driven compositional change in a solid. An ECM actuator producing micrometre-size displacements and long-term stability at room temperature was recently reported, comprising a 20 mol% Gd-doped ceria (20GDC), a solid electrolyte membrane, placed between two working bodies made of TiO x /20GDC (Ti-GDC) nanocomposites with Ti concentration of 38 mol%. The volumetric changes originating from oxidation or reduction in the local TiO x units are hypothesized to be the origin of mechanical deformation in the ECM actuator. Studying the Ti concentration-dependent structural changes in the Ti-GDC nanocomposites is therefore required for (i) understanding the mechanism of dimensional changes in the ECM actuator and (ii) maximizing the ECM response. Here, the systematic investigation of the local structure of the Ti and Ce ions in Ti-GDC over a broad range of Ti concentrations using synchrotron X-ray absorption spectroscopy and X-ray diffraction is reported. The main finding is that, depending on the Ti concentration, Ti atoms either form a cerium titanate or segregate into a TiO2 anatase-like phase. The transition region between these two regimes with Ti(IV) concentration between 19% and 57% contained strongly disordered TiO x units dispersed in 20GDC containing Ce(III) and Ce(IV) and hence rich with oxygen vacancies. As a result, this transition region is proposed to be the most advantageous for developing ECM-active materials.

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