According to an embodiment, a gas delivery device for a fuel cell system includes a hollow ceramic element comprising a dielectric material having at least one groove in one end face of the ceramic element and a first metal tube, wherein an end of the first metal tube is inserted into the groove of the hollow ceramic element. According to an embodiment, a fuel cell system includes a fuel cell stack or column, a gas delivery line fluidly connected to the stack or column, and a coefficient of thermal expansion compensator/isolator located in the gas delivery line, where the coefficient of thermal expansion compensator/isolator includes a hollow ceramic element made of a dielectric material having at least one groove in one end face of the ceramic element, a first metal tube, where an end of the first metal tube is inserted into the groove of the hollow ceramic element, and a hollow flexible element which compensates for differences in coefficients of thermal expansion between components of the fuel cell system.