For reliable use of lithium ion batteries,their cyclic propertymust be further improved. Several phase separating materials calledzero strain electrodes are very promising because they possess negligiblelattice mismatches at the phase interface and significantly reducethe mechanically induced deterioration. However, the structures andchemistry of actual phase interfaces are still not well understoodin this class of materials. In this study, the phase interfaces ofLi1+xRh2O4cubicspinel, one of the stable zero strain cathodes, are analyzed in anatomic scale using high-angle annular dark-field (HAADF)/annular bright-field(ABF) scanning transmission electron microscopy (STEM) and electronenergy-loss spectroscopy (EELS). Electrochemically induced phase interfacescan be clearly visualized in the ABF STEM images, where they tendto lie on {111} crystallographic lattice planes. The zero strain naturenear the observed interface can be confirmed by real space strainanalysis, which is in good agreement with the previous X-ray diffractionexperiments. By performing the canonical Monte Carlo simulations witheffective cluster interaction energies, it is concluded that the stabilityof {111} phase interfaces will be attributed to their small numberdensity of close lithium ionic pairs formed near the interface plane. [ABSTRACT FROM AUTHOR]