Effect of Gold Layer on Interface Resistance between Lithium Metal Anode and Li6.25Al0.25La3Zr2O12 Solid Electrolyte

A gold interlayer was introduced into the interface between Li6.25Al0.25La3Zr2O12 (Al-LLZ) and lithium metal anode to decrease their interfacial resistance. The interfacial resistance was decreased to 150 ohm from 1200 ohm by the introduction of gold interlayer with a heat-treatment at 150 degrees C, in which Li-Au alloy formation occurred. The interfacial resistance decreases with increasing the thickness of gold interlayer until 50 nm. Li/Au/Al-LLZ/Au/Li symmetric cell with the heat-treatment showed smaller overpotential for dissolution and deposition of lithium than Li/Al-LLZ/Li symmetric cell, due to difference in the interfacial resistance. From this result, it can be concluded that the gold interlayer is effective to decrease the interfacial resistance. (C) 2017 The Electrochemical Society. All rights reserved.