A spark plug 20 includes a center electrode 22 and a ground electrode 24 providing a spark gap 26 therebetween. At least one of the electrodes 22, 24, but preferably both electrodes 22, 24 include a clad surrounding a core. The clad includes at least one metal, such as nickel, iron, or cobalt. The core includes nanocarbon material embedded in a copper matrix 40 to increase the thermal conductivity and reduce the coefficient of thermal expansion of the core. The nanocarbon material includes a plurality of fibers 42, also referred to as particles, whisks, or tubes, each having a diameter of 1.0 to 150.0 nanometers and a length of 1 μm to 100 μm. The core includes the nanocarbon material in an amount of 0.1 to 10.0 wt. %.