In this work, we have therefore developed a meso-scale chemo-mechanical constitutive model by integrating the interplay between electrochemical reaction, anisotropic Li-ion intercalation, cathode microstructure, grain-level micromechanics and formation of crystal defects resulting from lattice dimension changes . We apply it to systematically investigate the impact of cathode microstructure, mechanical properties of solid electrolyte, and operating conditions on the evolution of stress and strain responses, generation of dislocations, as well as the associated oxygen loss and structural degradation mechanisms. Our work provides insights into the impact of grain-level chemo-mechanics on the degradation of Ni-rich composite cathodes, aiming at providing a quantitative simulation methodology for mitigating capacity loss of solid-state batteries.