Regensburg 2019 – wissenschaftliches Programm
CPP 15: Symposium SYCO of the divisions MM (leading), O, CPP, KFM and DS continued as topical session: Mechanically controlled electrical conductivity of oxides (joint session MM/CPP/O)
CPP 15.7: Vortrag
Montag, 1. April 2019, 18:15–18:30, H46
The impact of mechanical stresses on the ionic conductivity of nanoparticles — •Peter Stein1, Bai-Xiang Xu1, and Karsten Albe2 — 1TU Darmstadt, FB 11, FG Mechanik funktionaler Materialien — 2TU Darmstadt, FB 11, FG Materialmodellierung
Nanostructured electrodes have found wide application in electrochemical systems, for instance for lithium-ion batteries. This is due to their featuring short diffusion paths and large surface areas, allowing for comparatively fast surface reactions and transport within the slender bulk material. At this length-scale, surface stresses acting on the electrode surface induce a (non-uniform) pressure within the material, providing mechanical stabilization. As a result, nanostructured electrodes exhibit high reversible capacities and stable cycling behavior  as well as a higher robustness against mechanical degradation . However, the surface-induced pressure field also affects the electrochemical behavior of the particle, modifying, among other things, surface reaction rates and ionic mobility.
In this contribution, we discuss the interaction of mechanical stresses with the electrochemical behavior of nanostructured electrode particles. We thereby consider ideal analytical shapes, faceted nanoparticles, and regular nanostructures such as inverse opal electrodes. We further demonstrate the impact of surface-stress-induced mechanical fields on defect thermodynamics and kinetics, chemical reactions, and phase transformations.
 N. Zhao et al., Pure Appl. Chem. 80:2283-2295, 2008.  C.K. Chan et al., Nat. Nanotechnol. 3:31-35, 2008.