An electrochemical cell includes a bifunctional air cathode, an anode, and a ceramic electrolyte separator disposed substantially between the bifunctional air cathode and the anode. The anode includes a solid metal and an electrolyte configured to transition to a liquid phase in an operating temperature range. The electrolyte includes at least one of an alkali oxide, boron oxide, a carbonate, a phosphate, and a group III-X transition metal oxide.