In situ strain measurements and stress analysis of SiO@C composite electrodes during electrochemical cycling by using digital image correlation

SiO@C layer/copper foil composite electrode specimens were prepared and characterized by energy dispersive spectroscopy and thermogravimetric analysis methods, respectively. The related cycling performances, cyclic voltammetry and electrochemical impedance spectroscopy of SiO@C composite electrodes were discussed. Full/local strain field features of SiO@C composite electrodes were in situ measured during electrochemical cycles by designing a special electrolytic cell and digital image correlation technique. The corresponding stress variation characterizations of SiO@C composite electrode under different cycles were obtained by using a mechanical-chemical constitutive equation. The results are useful for revealing the volume expansion behaviors of SiO@C anode and the corresponding mechanical-chemical failure mechanisms.