The electrocatalytic oxidation of methane to ethane and ethylene has been carried out using an Li+ ion conductor as a solid electrolyte. The electrochemical cell used was Au I (Li2O)(0.17)(BaO)(0.07)(TiO2)(0.76) I Au, and the experiments were conducted at 850 degrees C with a mixture of 8.3% methane and 1.6% oxygen in argon. By applying an ac voltage of 3 V at a frequency of 10 Hz to the cell, the conversion of methane and the selectivity to C-2 hydrocarbons were enhanced 2 and 1.5 times more than at the open circuit, respectively.