Effect of Oxygen Defects Blocking Barriers on Gadolinium Doped Ceria (GDC) Electro-Chemo-Mechanical Properties

TL;DR

This study explores how oxygen defect configurations influence the electro-chemo-mechanical properties of gadolinium-doped ceria, revealing that oxygen vacancy distribution significantly impacts electrostriction beyond grain size and doping effects.

Contribution

It is the first investigation into the role of oxygen defect configuration on electro-chemo-mechanical properties of Gd-doped ceria, demonstrating the importance of vacancy distribution.

Findings

Oxygen vacancy distribution critically affects electrostriction.

Controlling defect configuration can enhance electro-mechanical performance.

Grain size and dopant diffusion are secondary to vacancy distribution.

Abstract

Some oxygen defective metal oxides, such as cerium and bismuth oxides, have recently shown exceptional electrostrictive properties that are even superior to the best performing lead-based electrostrictors, e.g. lead-magnesium-niobates (PMN). Compared to piezoelectric ceramics, electromechanical mechanisms of such materials do not depend on crystalline symmetry, but on the concentration of oxygen vacancy in the lattice. In this work, we investigate for the first time the role of oxygen defect configuration on the electro-chemo-mechanical properties. This is achieved by tuning the oxygen defects blocking barrier density in polycrystalline gadolinium doped ceria with known oxygen vacancy concentration, Ce0.9Gd0.1O2-x,x= 0.05. Nanometric starting powders of ca. 12 nm are sintered in different conditions, including field assisted spark plasma sintering (SPS), fast firing and conventional method at high temperatures. These approaches allow controlling grain size and Gd-dopant diffusion, i.e. via thermally driven solute drag mechanism. By correlating the electro-chemo-mechanical properties, we show that oxygen vacancy distribution in the materials play a key role in ceria electrostriction, overcoming the expected contributions from grain size and dopant concentration.