OPPO has introduced one of the latest products of its research and development as Zero-Power Communication, a new technology that might enable electronics to stay on by simply "harvesting" energy from other nearby devices that are using Bluetooth or Wi-Fi at the time. This potential replacement for batteries might end up as the way to sustain the IoT systems of the future.
https://www.notebookcheck.net/OPPO-claims-its-new-Zero-Power-Communication-technology-might-remove-the-need-for-batteries-in-some-electronics-of-the-future.595122.0.html
I have an idea that mobile phones can be a feature number to prevent them from being lost or stolen.
This is actually a tracking technology that is dual-use. It is presented as a for-civilian benefit, but actually it favors big government and tracking.