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Use of interplay between a-site non-stoichiometry and hydroxide doping to deliver novel proton-conducting perovskite oxides

DOI: 10.1002/aenm.202101337 DOI Help

Authors: Jin Goo Lee (University of St Andrews; Korea Institute of Industrial Technology) , Aaron B. Naden (University of St Andrews) , Cristian D. Savaniu (University of St Andrews) , Paul A. Connor (University of St Andrews) , Julia L. Payne (University of St Andrews) , Jonathan M. Skelton (University of Manchester) , Alexandra Gibbs (ISIS Facility) , Jianing Hui (University of St Andrews) , Stephen C. Parker (University of Bath) , John T. S. Irvine (University of St Andrews)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Advanced Energy Materials , VOL 8

State: Published (Approved)
Published: August 2021
Diamond Proposal Number(s): 17198

Open Access Open Access

Abstract: The magnitude of ionic conductivity is known to depend upon both mobility and number of available carriers. For proton conductors, hydration is a key factor in determining the charge–carrier concentration in ABO3 perovskite oxides. Despite the high reported proton mobility of calcium titanate (CaTiO3), this titanate perovskite has thus far been regarded as a poor proton conductor due to the low hydration capability. Here, the enhanced proton conductivity of the defective calcium titanate Ca0.92TiO2.84(OH)0.16 prepared by replacing lattice oxygens with hydroxyl groups via a solvothermal route is shown. Conductivity measurements in a humidified Ar atmosphere reveal that, remarkably, this material exhibits one order of magnitude higher bulk conductivity (10−4 Scm−1 at 200 °C) than hydrated stoichiometric CaTiO3 prepared by traditional solid-state synthesis due to the higher concentration of protonic defects and variation in the crystal structure. The replacement of Ca2+ by Ni2+ in the Ca1−xTi1O3−2x(OH)2x, which mostly exsolve metallic Ni nanoparticles along orthorhombic (100) planes upon reduction, is also demonstrated. These results suggest a new strategy by tailoring the defect chemistry via hydration or cation doping followed by exsolution for targeted energy applications.

Subject Areas: Materials, Chemistry, Energy


Instruments: B18-Core EXAFS

Other Facilities: ISIS

Added On: 27/08/2021 11:16

Documents:
aenm.202101337.pdf

Discipline Tags:

Physical Chemistry Energy Materials Chemistry Materials Science Perovskites Metallurgy

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) Extended X-ray Absorption Fine Structure (EXAFS)