Positive temperature coefficient polymer composition and positive temperature coefficient circuit protection device

A positive temperature coefficient (PTC) polymer composition for making a PTC circuit protection device, comprising:

• a polymer component;
• and
• a conductive filler component that is dispersed within said polymer component and that includes a first conductive filler and a second conductive filler, said first conductive filler being a zero-dimensional carbon-based material, said second conductive filler being one of a one-dimensional carbon-based material, a two-dimensional carbon-based material, and a combination thereof,
• wherein said first conductive filler is carbon black, and said second conductive filler is carbon nanotube and is present in an amount greater than 1 wt % and smaller than 15 wt % based on 100 wt % of said PTC polymer composition.