Which element has the highest thermal conductivity among metals? Silver. At ordinary temperatures, pure silver conducts heat more efficiently than any other metal. Its thermal conductivity is closely related to its exceptional electrical conductivity: mobile electrons move through silver’s crystal lattice and carry both electric charge and thermal energy.
Silver’s advantage does not mean it is the best practical choice for every heat-transfer application. It is expensive and relatively soft, so copper and aluminum are used far more often in heat sinks, cookware, heat exchangers, and industrial equipment. Copper conducts heat very well and costs much less, while aluminum is lighter and easier to manufacture into large components.
Diamond and some other nonmetallic materials can conduct heat better than silver, so the wording “among metals” matters. Gold is also an excellent conductor, but its thermal conductivity is lower than silver’s. Silver’s high cost means its thermal performance is usually reserved for specialized electronics, high-frequency components, and applications where thin silver coatings provide useful conductivity.