An air-breathing H2/air cell was designed for fast screening of electrolytes. In this study various electrolytes, including organic, inorganic, acidic, and basic electrolytes, were screened by comparing their effect on cell discharge performance. Focusing on organic alkaline electrolytes, several tetraalkyl ammonium hydroxide electrolytes with different molecular size and concentrations were investigated at different operating temperatures. Both electrolyte concentration and operating temperature significantly affect the cell's performance. The effect of CO2 and some acids on alkaline electrolyte's impedance and cell's discharge performance was also investigated.