In-situ study of mechano-electrochemical coupling properties of symmetrical SnO2/Gr electrodes for lithium-ion batteries using digital image correlation

Abstract

SnO2/Gr composite as anode material for lithium-ion batteries was synthesized by an acoustic-chemical method followed by an annealing treatment. The composite exhibits high crystallinity and purity, and the weight ratio of SnO2 is controllable. Benefit from the compound effect between material components, the SnO2/Gr anodes give notable reaction kinetics and cycling stability. The specific capacity of the composite with 27.4 wt% SnO2 remains 649.9 mA h g−1 after 170 cycles at 200 mA g−1. The strain field features in the symmetrical SnO2/Gr electrodes were in-situ measured during electrochemical cycles by digital image correlation technique. The distribution and variation characterizations of diffusion induced stress in the symmetrical SnO2/Gr electrodes were obtained by using mechano-electrochemical coupling constitutive equation. Furthermore, the contributions of the electrochemical and mechanical stress parts to the plane stress in the symmetrical SnO2/Gr electrodes also be discussed, respectively. The results and analytical method are critical for further revealing the failure mechanism and optimizing architecture of the SnO2/Gr electrodes for lithium-ion batteries.