Many electrical devices may be charged using induction chargers. The photograph shows a watch that is charged in this way and its charger.
Induction charging does not require a metal connection between the charger and the device.
The battery in the watch is charged by placing the watch on top of the charger.
The charger contains a coil. When the charger is plugged into the electrical supply, there is a current in this coil.
The watch also contains a coil in a circuit that includes the battery.