The overpotential and product selectivity characteristics of the high temperature solid electrolyte fuel cell , , , , , , air was studied at temperatures 800°–1000°C and atmospheric total pressure. The cell selectivity to could exceed 75% with simultaneous generation of ∼0.01 W/cm2 of electrical power. Electrochemical supply of oxygen to the fuel side has a positive effect on the cell selectivity to . The cell is a promising candidate for the cogeneration of electric energy and hydrogen cyanide.