Effect of Gold Layer on Interface Resistance between Lithium Metal Anode and Li_6.25Al_0.25La₃Zr₂O₁₂Solid Electrolyte

A gold interlayer was introduced into the interface between Li 6.25 Al 0.25 La 3 Zr 2 O 12 (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°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.