The influence of surface mechanics on diffusion induced stresses within spherical nanoparticles

Abstract

We examine the effects of surface tension and surface modulus on diffusion-induced stresses within spherical nanoparticles. We show that both the magnitude and distribution of stresses can be significantly affected by surface mechanics if the particle diameter is in the nanometer range. In particular, a tensile state of stress may be significantly reduced in magnitude or even be reverted to a state of compressive stress with decreasing particle radius. This reduction in tensile stress may be responsible for the observed resilience to fracture and decrepitation of nanoparticles used in various industrial applications.

Effects of size and concentration on diffusion-induced stress in lithium-ion batteries

“…Generally speaking, the smaller the electrode, the lower its DIS is. 20,26,33,48 The current outcome seems to be in contradiction with this viewpoint. Essentially, when the radius of an electrode is less than 50 nm, the size effect determines the stress increase based on the BOLS theory.…”

“…The stress continuously increases to the maximum value at its center, which is in agreement with previous results. 26,44 Obviously, the Biot number largely affects the distribution of radial stress during charging. As shown in Figure 4(c), the maximum tensile hoop stress appears at the center of an electrode while the maximum compressive stress is on the surface.…”

Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

“…Most continuum-level models of chemomechanical coupling have been developed to estimate diffusion-induced stresses-analogous to thermal stresses-which develop in the presence of a concentration gradient. A variety of single-particle models have been developed to estimate diffusion-induced stresses for battery electrode materials subjected to common electrochemical protocols [95][96][97] and incorporating a variety of effects including limited solid-solubility [98-100], particle shape [101,102], composition-dependent elastic modulus [103], and internal porosity [104]. Other particlelevel models have been developed which apply fracture mechanics failure criteria to study mechanical degradation of electrode materials, but these models considered static configurations-essentially the limit of zero rate-to identify critical length scales using fracture mechanics failure criteria.…”

Thermodynamics of electromechanically coupled mixed ionic-electronic conductors: Deformation potential, Vegard strains, and flexoelectric effect

“…Development of strains is a phenomenon ubiquitous in solid-state electrochemical devices including batteries [1,2], fuel cells [3,4] and electroresistive and memristive electronics. For example, strain is one of the dominant factors contributing to the mechanical instability of solid oxide fuel cells and Li-ion battery anodes such as intra-particle cracking and delamination of electrodes [5,6].…”