Nitpick: Copper has (slightly) better electrical conductivity than gold. But gold is often used to plate connector pins & sockets because it does not oxidize or tarnish.
Disney have developed an approach to generating small amounts of current from the movement of a conductor (aluminum foil) on an electret (charged Teflon). Basically you put the charged teflon between two layers of foil, and rub. The current is minimal, but sufficient to light LEDs or drive a static e-Ink display for a short time.
Basically, one foil sheet is the ground, and static to the electret. As the other sheet moves relative to the electret, the static electrical field pushes electrons in the moving sheet around, driving a small current flow.
It is pretty cool, but somewhat limited. I can’t imagine that a phone case made of this could be used to charge a phone, for example.
It would take a lot of vigorous rubbing - I can imagine the joke potential, though 