Apple has been working on devices with a wireless power transfer feature, better known as reverse charging for years. Today the US Patent & Trademark Office published a patent application from Apple that describes devices with wireless power transfer features and housings.

Apple notes in their patent filing that an electronic device can include a metallic or non-metallic housing having a window therethrough, a wireless power transfer coil disposed inside the housing adjacent the window, and a non-metallic cover disposed within the window that protects the wireless power transfer coil, the non-metallic cover incorporating at least one ferromagnetic region that improves magnetic coupling of the wireless power transfer coil to a corresponding wireless power transfer coil of another device by providing a high magnetic permeability flux path. The non-metallic cover and the at least one ferromagnetic region have surface finishes selected to visually match or coordinate with the housing.

Exemplary embodiments of ferromagnetic regions for use in devices with wireless power transfer features and housings. Such systems may be used in a variety of applications but may be particularly advantageous when used in conjunction with wireless power transfer systems electronic devices such as mobile phones, smart watches, and/or tablet computers including accessories for such devices such as wireless earphones, styluses, and the like. However, any system for which increased overall efficiency is desired may advantageously employ the techniques. This would technically include future MacBooks.

Apple's patent FIG. 6 below depicts an electronic device with a housing, a window therethrough for wireless power transfer, and a non-metallic cover incorporating ferromagnetic regions in the form of a ferrite with a cosmetic coating.

For more details, review patent application 20230275460.

Apple has been working on wireless power transfer (or reverse charging) for years. Here are a few Apple patents on this feature: 01, 02 and 03, with patent figures from the third patent presented below.