Xiaomi and Motorola’s over-the-air charging is vaporware until we can buy it

Chinese smartphone maker Xiaomi has teased an over-the-air wireless charging technology. Motorola today also teased its own similar air charging technology. Xiaomi's is called Mi Air Charge, while Motorola dubs its solution "One Hyper." They're the latest attempt at freeing smartphones from the (allegedly oppressive) constraints of charging cables and pads, with the promise to deliver energy from a distance.

Unshackle yourself — In a blog post, Xiaomi describes Mi Air Charge as able to "charge multiple devices simultaneously while you're gaming, walking around or even when something's in the way, no strings attached." The company says, however, that it will only offer 5-watts of charging power — not enough to charge a phone very quickly. But then, if you can top up all the time, does it need to be fast?

Motorola's One Hyper charger, meanwhile, was shown off in a video on Chinese social network Weibo. In the video, a person is seen placing two smartphones at varying distances away from a charger. Both phones appear to charge from a distance, though stop doing so when a hand obstructs the path between the charger and the phones.

Vaporware, for now — Powering devices through the air has been a dream of tech companies and consumers alike for decades, with promising inventors as far back as Nikola Tesla pitching new solutions only to have them fail for one reason or another. Perhaps the biggest flameout in recent history was uBeam, a startup founded in 2011 that raised $40 million for a wireless power transmitter it claimed could charge a phone from across a room using ultrasound frequencies. The company repeatedly missed self-imposed deadlines and to this day has never been able to demonstrate a functional product.

Xiaomi hasn't committed to releasing any devices with support for Mi Air Charge, so we're hesitant to give it much credibility based on a tweet. But the company does have a history of innovating on charging technology. Its Mi 10 Ultra, for instance, supports 50W wireless charging that can charge a supported phone on a pad in just 40 minutes — an impressive feat compared to wireless charging times offered by competing phones. Last year Xiaomi demonstrated an even better 80W wireless charger.

Though wireless chargers came on the scene with much fanfare, it's taken a while for them to become reliable and fast enough to really take hold. Truly wireless charging would change that — even if it's slower than using a cable, your phone could continuously charge as you move about a room.

Technical concerns — Physicists have long argued that safe, wireless electricity may never be viable. For uBeam or Mi Air Charge to work, you would theoretically need to shoot electricity out in every direction, and it begins to dissipate very quickly as you step away from the source. Charging up the air with an appreciable amount of energy could also be harmful to bodily health — possibly even burning skin. uBeam's former VP of engineering, Paul Reynolds, wrote a blog post in 2015 in which he said that its ultrasonic waves would emit too much heat to charge a phone safely.

All of that seems to explain why Xiaomi says Mi Air Charge only offers 5W charging. But if it works, it could pave the way for a revolution in how we charge our gadgets, from phones to wearables, headphones, and anything else with a rechargeable battery.