https://wccftech.com/iphone-macbook-future-charging-wirelessly-together/

A new patent application by Apple for published on Thursday outlines how two devices could top up each other’s batteries. This would enable users to use one Apple device with a battery charged at 100 percent to provide juice to the one that is at critical levels or drained completely. The ‘Inductive charging between electronic devices’ would also eliminate the need to carry around chargers and cables or to find an outlet and wait for the device to be charged.

This would be achieved by the inductive coils, which are already used in wireless charging systems to receive a charge. Apple proposes to use the same coils to transmit power to wirelessly charge one device using another.