In this work, a novel secondary Zn/air battery using protic Diethylmethylammonium trifluoro-methanesulfonate (DEATfO) ionic liquid as electrolyte and Pt/C as gas diffusion electrode was developed. The bi-functional activity of Pt/C GDE and the quasi reversibility of Zn electro-deposition/stripping in DEMATfO were demonstrated by using cyclic voltammetry method under half-cell conditions. The effect of temperature, humidity and cycling on cell performance was investigated under full-cell configuration with 0.01 M ZnTfO in DEMATfO. Interestingly, in dry air and ambient air, Zn/air cell was quite stable for about 700 h. The average cell voltage of Zn || DEMATfO + 0.01 M ZnTfO || Pt/C system was 1.2 and 1.8 V during discharging and charging step for 2 h each at 50 mu A cm(-2), respectively. First experiments in ambient air were also very promising. However, maximal cell power density was relatively low (45 mu W cm(-2)). This can be explained by low contact angle of the IL on GDE substrate that presumably hindered triple-phase boundary formation. (C) The Author(s) 2017. Published by ECS. All rights reserved.