As shown in Fig. and, our results suggest that regions with lower Li content exhibit smaller changes in peak posi-on, i.e., smaller laoce constant varia-ons, during lithia-on/delithia-on compared to regions with higher Li content. The varia-ons of the Gibbs free energy curves in this case are illustrated in Fig. , where we assumed that the α chem of the Li-poor phase is considerably smaller than that of the Li-rich phase. The common tangent lines under stress and without stress under these condi-ons are represented by the solid black and grey dashed lines, respec-vely. In this case, the two-phase region becomes narrower under stress, because the different α chem for both phases leads to the addi-on of a different linear term to each phase. These discussions qualita-vely reveal that for the stress to thermodynamically affect the two-phase region of electrode materials including FMO, the α chem of each phase must differ. Moreover, the magnitude of the stress-induced varia-on of the two-phase region is dependent on the difference in the α chem between the phases, rather than the absolute values of α chem for each phase, with larger differences resul-ng in more pronounced varia-on in the two-phase region. Based on the above discussions, it is suggested that the lithia-on/delithia-on mechanism of FMO on a solid electrolyte could be varied due to the stress generated by the substrate constraints because the α chem of the Li-rich and Li-poor phases of FMO were different. As shown in the above discussion, when applying two-phase electrode materials including FMO to ASSLIBs, it is important to consider not only the difference in laoce constants between the phases, which determines the magnitude of the chemo-mechanical stress, but also the disparity in α chem , as it governs the influence of stress on the (dis)charge mechanism.