Operando Spectroscopic Studies of Solid Oxide Fuel Cell Operation Using Dimethyl Ether as an Alternative Fuel

Dimethyl ether (DME) is an oxygen-containing fuel that is an attractive alternative to the reforming of light alkanes like CH 4 . Its higher volumetric exergy compared to CH 4 yields comparable power densities to other fuels while decreasing its potential for performance degradation that results from coking. We have characterized an SOFC operating at 800 °C on DME using a suite of operando optical and ex post facto methods. Based on exhaust gas infrared spectroscopy, DME decomposes to CH 4 , C 2 H 2 , H 2 O, CO 2 , and CO. Electrochemical analysis indicates that under dry DME the maximum power output of an anode supported button cell Ni-YSZ SOFC is only 10% lower than under CH 4 (where H content was matched in the fuel stream). FTIR analysis of the anode exhaust gas indicates an electrochemical response under galvanostatic conditions resulting in the consumption of both CH 4 and C 2 H 2 to form CO, CO 2 , and H 2 O. Operando near-infrared thermal imaging reveal more cooling at the anode surface with DME than CH 4 resulting from increased endothermic cracking of CH 4 . Additional contributions to the cooling are possible from reforming reactions.