Surface　passivation　has　become　a　routine　strategy　of　design　to　mitigate　the　chemomechanical　degradation　of　high-capacity　electrodes　by　regulating　the　electrochemical　process　of　lithiation　and　managing　the　associated　deformation　dynamics.　Oxides　are　the　prevalent　materials　used　for　surface　coating.　Lithiation　of　SiO2　leads　to　drastic　changes　in　its　electro-chemo-mechanical　properties　from　an　electronic　insulator　and　a　brittle　material　in　its　pure　form　to　a　conductor　and　a　material　sustainable　of　large　deformation　in　the　lithiated　form.　We　synthesized　SiO2-coated　SiC　nanowires　that　allow　us　to　focus　on　the　lithiation　behavior　of　the　sub-10　nm　SiO2　thin　coating.　We　systematically　investigate　the　structural　evolution,　the　electronic　conduction　and　ionic　transport　properties,　and　the　deformation　pattern　of　lithiated　SiO2　through　coordinated　in　situ　transmission　electron　microcopy　experiments,　first-principles　computation,　and　continuum　theories.　We　observe　the　stress-mediated　reaction　that　induces　inhomogeneous　growth　of　SiO2.　The　results　provide　fundamental　perspectives　on　the　chemomechanical　behaviors　of　oxides　used　in　the　surface　coating　of　Li-ion　technologies.