Dynamic changes in charge-transfer resistance at Li metal/Li_7La_3Zr_2O_(12) interfaces during electrochemical Li dissolution/deposition cycles

摘要

Dynamic changes in the charge-transfer resistance at a Li/Li7La3Zr2O12 (LLZ) interface during lithium (Li) dissolution/deposition cycles are investigated with an alternative current (AC) impedance technique in a three electrode system. The resistance respectively increases and decreases during electrodissolution and electrodeposition of Li. The resistance does not return to the initial value after one cycle of Li dissolution and deposition, which indicates that the change in resistance during dissolution is larger than that during deposition. Furthermore, the resistance is almost constant when Li deposition proceeds without prior Li dissolution. The respective increase and decrease in the interfacial resistance during Li dissolution and deposition is most likely due to the formation and disappearance of voids at the Li/LLZ interface, and the voids formation during Li dissolution is suggested to be a critical factor that influences the interfacial resistance.