Cycling-induced structural damage/degradation of electrode materials–microscopic viewpoint

Abstract

Most analyses of the mechanical deformation of electrode materials of lithium-ion battery in the framework of continuum mechanics suggest the occurring of structural damage/degradation during the de-lithiation phase and cannot explain the lithiation-induced damage/degradation in electrode materials, as observed experimentally. In this work, we present first-principle analysis of the interaction between two adjacent silicon atoms from the Stillinger–Weber two-body potential and obtain the critical separation between the two silicon atoms for the rupture of Si–Si bonds. Simple calculation of the engineering-tensile strain for the formation of Li–Si intermetallic compounds from the lithiation of silicon reveals that cracking and cavitation in lithiated silicon can occur due to the formation of Li–Si intermetallic compounds. Assuming the proportionality between the net mass flux across the tip surface of a slit crack and the migration rate of the crack tip, we develop analytical formulas for the growth and healing of the slit crack controlled by lithiation and de-lithiation, respectively. It is the combinational effects of the state of charge, the radius of curvature of the crack tip and local electromotive force that determine the cycling-induced growth and healing of surface cracks in lithiated silicon.

Application of Carbon Fiber Cement-Based Composites in Improving Construction Durability

“…It has many characteristics, such as lightweight, high strength, excellent conductivity, and high elastic modulus. It is favored by researchers at home and abroad in many fields [ 2 ].…”

Chemical stress in a largely deformed electrode: Effects of trapping lithium

“…Hüger et al. 63 experimentally revealed nearly uniform distribution of lithium in the form of solid and condensed Li 0.3 Si compound throughout lithiated amorphous silicon films, which supports the analysis by Yang 64 that the lithiation of silicon with local atomic ratio of lithium to silicon less than 12/7 can likely mitigate the formation of nanopores associated with the rupture of silicon-silicon bonds. The approach used by Hüger et al.…”

Numerical Analysis of Degradation and Capacity Loss in Graphite Active Particles of Li-Ion Battery Anodes

“…As we observe in Figure 4 , this was a time-dependent phenomenon, and the most important stress gradients took place during the first seconds of the process. This crack formation mechanism has been discussed in models of the cracking behavior of active Li-ion batteries particles, both in early and current mathematical models [ 14 , 18 ], as well as in numerical–experimental models [ 51 , 52 , 53 ] and also in 3D tomography of single particles at different states of charge [ 54 ]. For the sake of clarity, we have not included the failure process in these results ( Figure 4 ).…”