Enables the transmembrane transfer of an ion by a voltage-gated channel. An ion is an atom or group of atoms carrying an electric charge by virtue of having gained or lost one or more electrons. A voltage-gated channel is a channel whose open state is dependent on the voltage across the membrane in which it is embedded. [ GOC:mtg_transport https://www.worldcat.org/search?q=bn%3A0815340729 https://www.worldcat.org/search?q=bn%3A0198506732 ]