A configuration for the coplanar, single-chamber solid oxide fuel cell has been proposed and operated successfully in a methane-oxygen mixture (CH4:O-2=2:1) with a total flow of 300 mL min(-1). It was fabricated by attaching the Ni/yttria-stabilized zirconia (YSZ) anode and the Sm0.2Ce0.8O1.9-impregnated La0.7Sr0.3MnO3 cathode in two parallel grooves of the YSZ substrate. With the electrolyte wall fabricated between the anode and the cathode, the configuration obviously extends the conductive channel of oxygen ion transport and forms a gas separator between the electrodes, leading to a remarkable reduction in ohmic resistance, an elevation of open-circuit voltage, and, ultimately, an improved performance.