An ice maker of a domestic refrigerator that includes an ice mold having an electrically-conductive polymeric body and a plurality of cavities defined in the polymeric body. Each cavity is sized to receive a quantity of fluid corresponding to a single ice cube. A pair of electrodes is engaged with a bottom surface of the polymeric body. The polymeric body has a first electrical conductivity at a first operating temperature and a second electrical conductivity that is less than the first electrical conductivity at a second operating temperature. The second operating temperature is greater than the first operating temperature.