The influence of crystal orientation on the change in Li chemical potential of LiCoO2 under mechanical stress

Change of the lithium chemical potential in a crystalline LiCoO2 with the application of a mechanical stress was discussed based on the results of electromotive force (emf) measurements between preferentially-oriented LiCoO2 films on Li0.33La0.55TiO3 solid electrolytes under mechanical stress. [00l]-oriented LiCoO2 films with different degrees of orientation were prepared, and it was investigated how the direction of mechanical stress to the crystal lattice affects emf. It is found that emf emerged when mechanical stress was applied. The magnitude of emf under stress was dependent not only on the magnitude of applied stress but also the degree of the film orientation. This clearly demonstrated that the crystal orientation, i.e. the direction of mechanical stress to the crystal, affects the lithium chemical potential.