Self-Charging Phones Are on the Way, Finally
The case that Will Zell slides onto his iPhone doesn’t look that unusual, but it’s doing something pretty out of the ordinary: capturing some of the radio waves that the phone transmits when connecting to cell-phone towers and Wi-Fi routers, converting them to electricity, and feeding that power back to the phone’s battery.
Zell is the CEO of Nikola Labs, a startup based in Columbus, Ohio, whose energy-harvesting technology was invented by Chi-Chih Chen, a research associate professor of electrical and computer engineering at Ohio State University. Like battery pack cases, the company’s case plugs into the bottom of the iPhone; this way, Zell says, it can intermittently send power right to the battery.
Moore’s Law, which predicts that the number of transistors on a chip doubles every two years, has held steady since 1975. Yet battery technology hasn’t kept the same pace, probably because its evolution is dependent on advances in chemistry. So while smartphones have gotten increasingly capable, with faster processors, better displays, and higher-resolution cameras, it can still be a challenge to get the battery that’s powering all these features to last throughout the day.
One way the consumer electronics industry is trying to fix this is by aligning with wireless charging technologies like Qi and Rezence. So far, though, only a handful of smartphones from companies like LG, Samsung, and, HTC use the Qi standard, while Rezence-supporting handsets are set to come out later this year.
With such wireless charging still far from the mainstream (and still requiring your phone to be on a charging mat or base that itself plugs into a wall), a few companies, including Nikola Labs, are trying to figure out other ways to make you less dependent on outlets so you can keep using your phone for battery-intensive things like looking at websites, navigating trips, and streaming videos.
They won’t make plugging your phone into a charger obsolete, but Zell says that Nikola’s phone case should be able to give users about 25 to 30 percent more battery life between charges. The company built its first working prototype of a smartphone case this spring and plans to start selling it in the first three months of next year for about $100 (a Kickstarter campaign for the company had raised about $74,000 of its $135,000 goal with eight days to go as of publication; Zell says Nikola Labs has separately raised private funding to bring its product to market).
Though Zell acknowledges that there’s plenty of skepticism surrounding the utility of harvesting energy from radio waves, he says Nikola Labs’ technology works because it’s doing the harvesting so close to the transmitting antenna in the phone, and that it’s capturing radio waves that aren’t needed for communication in order to avoid impacting call quality. Eventually, he hopes to fit the technology into the phone itself; early talks with phone makers have begun.
A French solar technology company called Sunpartner Technologies is already working on this with a thin, see-through overlay called WYSIPS Crystal (the acronym stands for “what you see is photovoltaic surface”) that sits between the glass and touch-screen layers on a smartphone or other mobile gadget. The WYSIPS layer is covered with small solar cells; when the phone is exposed to artificial or natural light, it captures the light and converts it to an electric current. A connection to the gadget’s battery would enable the layer to send power directly to it.
WYSIPS Crystal marketing director Matthieu de Broca says that Sunpartner is working with Kyocera, which makes a number of ruggedized handsets, to get WYSIPS Crystal into phones next year.
But while De Broca says the energy WYSIPS Crystal can produce depends on the kind of light it’s exposed to—intense natural light will work better than diffuse indoor lighting—in its current form it can boost battery life by only about 10 to 15 percent.
“It will never be able to produce enough to charge the phone from scratch,” he says.
Much clunkier but perhaps more suited to that job is a wearable charger from Ampy, a startup based in Evanston, Illinois. The device contains a battery you fill up by moving around.
“We’re pretty active people,” says Ampy cofounder and CEO Tejas Shastry of himself and his cofounders. “So we thought, ‘Why can’t we harvest some of the energy from motion to power our phones?’”
The charger, which is the size of a deck of cards, contains inductors—essentially, magnets moving within a coil. Shastry says the inductors are activated as you move during activities like walking, running, or cycling, generating electricity that’s stored in an internal battery (users have to connect their phone to Ampy to siphon off its juice). The battery inside Ampy can store enough power to fully recharge a smartphone. It might take a while to get to that point, though, since an hour of exercise yields about an hour of “normal” smartphone usage, according to Ampy’s website.
The company raised $310,000 on Kickstarter last fall, which was more than three times its goal, and plans to ship out the first Ampy gadgets in the fall to crowdfunding backers and people who preorder it online.
To succeed on a wider scale, though, these companies must improve the ways the devices produce and use power and then convince mainstream consumers to buy them. And you’ll probably continue plugging in your phone at least occasionally for the foreseeable future.
But Nikola Labs’ Zell, at least, is optimistic that this could eventually change. “Ultimately what I’d love to create is where thinking about battery life is no longer something that’s in everyone’s minds,” he says. “What if you just didn’t have to consider it?”
Geoffrey Hinton tells us why he’s now scared of the tech he helped build
“I have suddenly switched my views on whether these things are going to be more intelligent than us.”
ChatGPT is going to change education, not destroy it
The narrative around cheating students doesn’t tell the whole story. Meet the teachers who think generative AI could actually make learning better.
Meet the people who use Notion to plan their whole lives
The workplace tool’s appeal extends far beyond organizing work projects. Many users find it’s just as useful for managing their free time.
Learning to code isn’t enough
Historically, learn-to-code efforts have provided opportunities for the few, but new efforts are aiming to be inclusive.
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.