An efficient, reliable and cost-effective energy storage is necessary to increase the use of renewables and to contribute in reducing the carbon footprint of the electricity grid. A novel iron-air battery characterized by high performance, safety and reliability for operation at intermediate temperatures (500–650 °C) is demonstrated. The iron-air rechargeable battery is based on a new configuration where both the nickel-electrode and the hydrogen/water redox processes, generally utilized in high temperature ceramic batteries, are avoided in this system completely operating in the solid state. This can increase the durability and reliability of the battery while providing excellent performance (specific energy of 0.46 Wh g−1, specific capacity of 0.5 Ah g−1, faradaic efficiency 80%). These characteristics favourably compare to low temperature iron-air batteries. Excellent performance and cyclability are achieved at 650 °C for the iron-air solid-state battery showing no relevant degradation after more than 100 cycles. The concept is based on a composite iron-ceria anode in contact with an oxygen anion-conducting lanthanum gallate electrolyte and a mixed conductivity lanthanum ferrite perovskite-based cathode. This combines both simplicity of operation and intrinsic safety with high energy density and durability. The excellent dynamic behaviour, the absence of influence of external environmental conditions and the use of cost-effective ceramic materials, with the possibility to produce high quality heat to cover the chain of electrical and thermal energy, make such systems largely appealing for applications related to renewable power sources.