A new patent filed by Sony has gone public and it seems that they are working on a wireless charging attachment for their controllers.
A description of the patient states:
A wireless charging adapter that can snap onto a computer game controller can be inductively coupled to a charging base to wirelessly recharge a battery in the controller. The adapter also can include keys that mirror keys on the controller so that a gamer can remove the adapter with controller from the charging base, keep the adapter on the controller, and use both the controller keys and adapter keys to control a computer game.
This would have a charge sent via wireless communication between the base and the attachment. Then the attachment would then charge the battery of the controller.