Remote (or over-the-air) charging is a futuristic technology that a handful of mobile device OEMs claim to have cracked in 2021 thus far. The latest of these is OPPO, a company that has released a video of its new breakthrough in conjunction with MWC Shanghai. It also features OPPO's slidable-display phone, shown charging without cables or pads of any kind.
https://www.notebookcheck.net/OPPO-is-the-latest-OEM-with-an-over-the-air-charging-technology-demo.524105.0.html