Self-Organized Core-Shell Structure for High-Power Electrode in Solid-State Lithium Batteries

Effect of Al-substitution for Co on the electrode properties of LiCoO(2) is investigated in a sulfide solid electrolyte. The substitution decreases the electrode resistance and thus improves the high-rate capability. Investigation of the post-annealing effect revealed that, although the crystal structure or morphology of the LiAl(x)Co(1-x)O(2) are not significantly changed by the post-annealing, the electrode properties are highly dependent on the post-annealing conditions, which suggests that the improvement in high-rate capability comes from the change in surface structure of the LiAl(x)Co(1-x)O(2) particles (i.e., self-organized core-shell structure). The Al-substituted LiCoO(2) obtained through this study delivers a discharge capacity of 115 mAh g(-1) at 1 C and 84 mAh g(-1) even at a high discharge rate of 5 C at 25 degrees C, which is one of the highest rate capabilities observed in solid-state cells.