A High-Temperature Metal-Air Battery (HTMAB) prototype based on a simple redox reaction between molten Sn and atmospheric oxygen at 800 degrees C is presented, using yttria doped zirconia as solid electrolyte. Basic reversibility measurements indicate that the electrochemical reactions in the device are reversible with coulombic efficiencies higher than 95%. Significant influence of the cycling rate in "the delivered capacity is detected; specifically it is increased from 8 to 90 mAh cm(-2) when reducing the discharge current from 12.5 to 0.56 mA cm(-2). EIS analysis performed over cycling shows that anode diffusion polarization increase due to sealing deficiencies is the main cause of degradation. Anyway, the electrochemical Sn oxidation reduction reaction remains reversible for more than 4500 charge discharge cycles and 6000 hours operating at 800 degrees C. (C) 2016 Elsevier Ltd. All rights reserved.