Tech
Solid-state device harvests body heat to power battery-free wearables and IoT sensors
A research team affiliated with UNIST has unveiled a technological advancement that allows body heat to generate electricity sufficient to power electronic devices. This innovation paves the way for the commercialization of battery-free wearable gadgets and Internet of Things (IoT) sensors that operate solely on heat generated by the human body.
Led by Professor Sung-Yeon Jang from the School of Energy and Chemical Engineering at UNIST, the research team developed the world’s first high-performance n-type solid-state thermogalvanic cell capable of powering actual electronic devices. The paper is published in the journal Energy & Environmental Science.
Thermogalvanic cells are compact generators that convert temperature differences—such as the human body temperature (~36°C) versus surrounding air (20–25°C)—into electrical energy. However, due to the minimal temperature gradient, previous systems struggled to produce enough power to operate real-world electronics.
The newly developed solid-state device overcomes this challenge by delivering sufficient voltage and current to power practical devices. While solid-state designs typically offer advantages such as safety from leakage, ion mobility issues within the electrolyte have historically limited their current output. The research team engineered an electrolyte that facilitates efficient ion transport, and further, the thermally driven ion diffusion enhances overall output voltage.
By connecting 100 of these cells in series—similar to building with LEGO blocks—approximately 1.5V can be generated from body heat, comparable to standard AA batteries. Connecting 16 such series-connected modules enables the activation of devices like LED lights, electronic clocks, and temperature/humidity sensors.
Notably, the cell’s Seebeck coefficient (voltage change per temperature difference) is –40.05 mV/K, representing up to a fivefold increase over conventional n-type cells. The device also demonstrated excellent durability, maintaining consistent performance after 50 charge-discharge cycles.
The core of this solid-state cell comprises a conductive polymer, PEDOT:PSS, and a redox couple of Fe(ClO₄)₂/3. Electrostatic interactions between the negatively charged sulfonate groups (–SO₃⁻) of the polymer and the Fe²⁺/Fe³⁺ ions establish a stable structure, while perchlorate ions (ClO₄⁻) are free to move, facilitating ion diffusion and thermodiffusion effects that boost power output.
Professor Jang stated, “This research marks a new milestone in low-temperature waste heat energy harvesting and flexible energy conversion devices. It has the potential to serve as a self-powered system for wearable electronics and autonomous IoT devices driven solely by body heat.”
More information:
Jeong-Ye Baek et al, Solid-state n-type thermodiffusion-assisted thermogalvanic cells with unprecedented thermal energy conversion, Energy & Environmental Science (2025). DOI: 10.1039/D5EE01216C
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Solid-state device harvests body heat to power battery-free wearables and IoT sensors (2025, September 8)
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Whether you’re a hardcore athletics aficionado or just nurturing a newfound love of hockey thanks to Heated Rivalry, the 2026 Winter Olympics have what you’re looking for.
The Milano Cortina 2026 Winter Olympics will take place across Milan and Cortina, Italy, throughout the month of February. A few competitions start on February 4, but the opening ceremony will be held on February 6 at 2:00 pm ET and will feature performances by Mariah Carey and Andrea Bocelli. Following the events, there will be a closing ceremony on February 22 at 2:30 pm ET.
As in Olympics past, this year’s games will be televised in the US exclusively by NBC. You can watch if you have cable or satellite TV. Cable coverage will be across several NBC channels, including NBC local affiliates, CNBC, and the USA Network.
The Games will also be shown live on NBC’s streaming service Peacock Premium, which requires a subscription of $11 per month. If ads drive you bonkers, the ad-free Peacock Premium Plus costs $18 a month. (Set a calendar reminder to cancel the service after the Olympics if you’re not planning to keep watching Traitors.)
Peacock will also bring back its Olympics hub website, which may be the easiest way to find the events you’re looking for. You can search and bookmark sports or events ahead of time and get notifications for when they go live. This might be especially useful depending on what time zone you’re in, as the games are all taking place in northern Italy, which is in the GMT+1 time zone.
For a full overview of all the events, check out the official Olympics competition schedule. If you’d like to see each and every competition listed in order by event time, we have you covered.
Looking for events by sport? Below is a list of the big events for them all, along with links to the full schedules of every event.
Note: Unless specified otherwise, all times below are listed in US Eastern time.
Opening Ceremony
The three-hour-long opening ceremony will air on nearly every Olympic media outlet on Friday, February 6. Live coverage starts at 2 pm Eastern and 11 am Pacific.
Alpine Skiing
Training for alpine skiing starts on February 4, but the competitive events kick off with men’s downhill on February 7 at 5:30 am. The first medal event for women’s downhill is February 8.
Medal events occur nearly every day through February 18. Final medal games start with the first men’s slalom run on February 16.
Women’s final slalom runs start February 18.
Biathlon
Biathlon events are the closest thing the Olympic games get to a James Bond movie. Skiers zip across mountain trails and then stop to shoot a gun. What’s not to love?
You can watch all the excitement starting with a mixed relay 4 x 6 km on February 8.
All events are medal events and go until the men’s 1- km mass start on February 20 and women’s 12.5-km mass start on February 21.
Bobsleigh
Bobsleigh—no, not bobsled, you philistine—events start February 12. One of the three sliding sports, bobsleigh is a team of two to four people sitting upright in a sled with their heads poking out. (As opposed to luge and skeleton, in which athletes lay on their sleds without sides or backing.)
Training events start on February 12 at 6:50 am. There are four bobsleigh medal events, starting with heat four of the women’s monobob on February 16.
You don’t need a four-figure Swiss movement to know what time it is—or look good doing it. One of the most wonderful things about “budget” watches today (although it’s kinder, or more appropriate, to say “affordable”) is that brands have learned to take design cues from luxury timepieces while quietly getting very good at the fundamentals: reliable movements, thoughtful materials, and proportions that don’t scream “cheap.” Take a look at the Orient in WIRED’s selection below as a prime example.
It could easily be argued that we’re in a golden age of affordable horology (see our full guide here for definitive proof), where, if you choose wisely, $350 or less can buy everything from a desirable dress watch, or a high-end collaboration, and even a supremely capable and classically chic diver. Pieces that will see you right from sunken wreck to boardroom table. And let’s not forget the retro allure of digital watches right now, either, with the Shark Classic not only being one of our favorites here, but at $70, it’s also the most affordable.
Moreover, should you decide to bag more than a few (and who could blame you at these prices?), we’ve even got the perfect carry case picked out: Nanuk’s IP67 waterproof and dustproof NK-7 resin $175 910 Watch Case (pictured above) with patented PowerClaw latching system—ideal for securing any timepiece collection, be it bargain or big budget.
Be sure to check out our other wearable coverage, including the Best Budget Watches Under $1,000, Best Smartwatches, Best Fitness Trackers, and Best Smart Rings.
Same as the Five Senses deck above, this scratch-off card set happens in sequence, with optional “level up” cards to really push intimacy, and separate cards for each partner with secret directions. For this date, you’ll both bring a red item that you show at certain points to signify that you’re open to physical touch. Then you’ll go out to dinner and have intentional conversation, and every time a partner pulls out the red item, you’ll follow the prompts to initiate increasingly intimate physical acts, ranging from hand holding to neck kisses. So there we were, at Illegal Taqueria, edging each other over al pastor tacos (I kid).
Many of the cards urged a partner not to interrupt or solve problems, but ask questions and talk dirty. My date said, “I think this may be for couples who hate each other.” I had to agree. The second part of the date involved driving and stoplights, but since we were in Brooklyn, we walked down the trash-filled sidewalk and pretended to be a suburban couple on the fritz instead.
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Date: Greg, 10/10 (Note: I didn’t find this man on Hinge; I met him the old-fashioned way, in a bar at 2 am.)
Box: 6/10
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