Harvesting　the　promising　high　energy　density　of　advanced　electrode　materials　in　lithium-ion　batteries　is　critically　dependent　on　a　mechanistic　understanding　on　how　the　materials　function　and　degrade　along　with　the　battery　cycling.　Here,　we　tracked　phase　transformations　during　(de)lithiation　of　Sb2Se3　single　crystals　using　in　situ　high-resolution　transmission　electron　microscopy　(HRTEM)　technique,　and　revealed　electro-chemo-mechanical　evolution　at　the　reaction　interface.　The　effect　of　this　electro-chemo-mechanical　coupling　has　a　complicated　interplay　on　the　lithiation　kinetics　and　causes　various　types　of　defects　at　the　reaction　front,　including　dislocation　dipoles,　antiphase　boundaries,　and　cracks.　In　return,　the　formed　cracks　and　related　defects　build　a　path　for　fast　diffusion　of　lithium　ions　and　trigger　a　highly　anisotropic　lithiation　at　the　twisted　reaction　front,　giving　rise　to　the　formation　of　presumably　＂dead＂　Sb2Se3　nanodomains　in　amorphous　LixSb2Se3.　The　detailed　mechanistic　understanding　may　facilitate　the　rational　design　of　high-capacity　electrode　materials　for　battery　applications.