Interactions Between Non‐Stoichiometric Stresses and Defect Transport in a Tubular Electrolyte

Abstract

It is well known that gadolinium doped ceria (10 GDC) undergoes significant compositional expansion when exposed to low oxygen partial pressures. When constrained, such expansion results in mechanical stresses in the ionic solid. Although significant work has been done in evaluating the magnitudes of this expansion, interactions between stresses induced as a result of chemical expansion and transport of point defects in a solid electrolyte have not received much attention. In this work, the formulation developed by Swaminathan et al. in ref. [1] for coupling transport and mechanical stresses in an ionic solid is used to numerically study the effects of transport–stress interaction in a tubular solid electrolyte made of 10 GDC. The results obtained in this study indicate a strong interaction between transport and stresses, showing a significant variation in the electrochemical performance of the electrolyte under varying conditions of stress–transport interaction. The solutions obtained in this study reduce to the well‐known results in the literature when chemical expansion is not considered, thereby partially validating our results.

Interface-reaction controlled diffusion in binary solids with applications to lithiation of silicon in lithium-ion batteries

“…Existing theories are all based on small strain deformation. Second, such large volumetric change, if not accommodated by appropriate deformation, will generate mechanical stresses, which will in turn affect the diffusion (Swaminathan and Qu, 2007;Swaminathan et al, 2007a,b;Swaminathan and Qu, 2009;Cui et al, 2012b). None of the existing theories accounts for such two-way interaction.…”

Strong stress-enhanced diffusion in amorphous lithium alloy nanowire electrodes

“…In this paper, we study the fully two-way coupling between stress development and diffusion in an amorphous Li Si NW using the large deformation framework of Wu 16 previously used to model selective oxidation of alloys 17,18 and defect migrations in ionic solids. 19,20 At issue is the significant contribution of stress gradient to the driving force for diffusion which has hitherto been neglected for amorphous alloy electrodes. We consider the short-term response and the long-term behavior to highlight the important effects at work in different stages of charge/discharge cycles.…”

Analysis of oxygen exchange-limited transport and chemical stresses in perovskite-type hollow fibers

“…Atkinson [16], Atkinson and Ramos [17] and Hendriksen et al [18] calculated the chemical stresses in membranes under steady-state oxygen vacancy transport conditions. The chemically induced stresses in transient state in SOFC interconnects and in a tubular SOFC electrolyte have been found by Yakabe et al [19,20], and Swaminathan and Qu [21], respectively. Thermal and chemical stresses in non-steady state in ion-conducting perovskite-type membranes have been investigated by Blond and Richet [22].…”