Dislocation mediated Li diffusion. Bragg coherent diffraction imaging characterisation and chemo-mechanical phase-field dislocation modeling indicate that discrete dislocations can result in large lattice mismatch and nonuniform stress fields near dislocations in electrode materials. These stress-strain fields around dislocations can potentially alter the overall Li diffusion behaviour and Li concentration distribution . For example, chemo-mechanical phase-field simulations have demonstrated that there is strong Li enrichment and depletion in the tensile and compressive stress fields around the dislocation, respectively, in LiMn 2 O 4 cathodes . Additionally, pipe diffusion can be initiated on the tensile stress side of edge dislocations . Moreover, recent advancements in strain engineering have employed dislocations to tune ionic transport properties in Li-ion conducting argyrodites Li 6 PS 5 Br . These findings suggest that inducing internal strain and dislocations in the structure of argyrodites through applying uniaxial and hydrostatic pressures can promote Li-ion disorder, and lead to higher Li-ion conductivity . Although the current model in this study does not explicitly describe the effect of Grain boundaries in polycrystalline cathodes. Grain boundaries, with their distinct physicochemical properties compared to the bulk, noticeably affect Li transport, mechanical failure, and structural degradation in polycrystalline NMC cathodes . For example, the low diffusion barriers of TM ions along grain boundaries can promote TM ion dissolution and accelerate formation of rock-salt phases . Additionally, the atomistic structures of various grain boundaries, such as local structural distortion and charge redistribution, can significantly influence Li transport kinetics . Conductive atomic force microscopy characterisation shows that grain boundaries can generally act as fast pathways for Li transport in LiCoO 2 . First-principles calculations reveal that the coherent Σ2 grain boundaries enhance Li migration both along and across the grain boundary plane, whereas the asymmetric Σ3 grain boundaries substantially impede Li transport in NMC cathodes . The role of grain boundaries in Li transport kinetics can be incorporated into the chemo-mechanical model by considering the chemical potential or concentration jumps across grain boundaries .