Wearable Wireless Charging Fabric VoltCore: Turning an Entire Garment Into a Phone Charger

VoltCore, jointly developed by Japan's NTT Docomo and materials giant Toray, is a breakthrough for consumer electronics. The smart fabric has wireless charging capability and turns the wearer's entire garment into a large-area wireless charging station. Phones, smartwatches, and earbuds placed in a pocket charge automatically, with no cables or charging pads required.

At the core of VoltCore is a conductive fiber woven with copper coils. The fiber keeps the softness and washability of ordinary fabric while gaining electromagnetic induction capability. At 0.18 millimeters in diameter, it is slightly thicker than standard cotton yarn, but woven into cloth it feels almost identical to ordinary cotton.

The charging principle relies on magnetic resonance coupling. VoltCore garments carry a small power management module that draws input power from a compact lithium battery in a pocket or from the wearer's phone, then radiates an alternating magnetic field through the copper coil array embedded across the fabric. When a phone or other device enters that magnetic field, the receiving coil inside the device harvests the energy.

In practical charging speed, NTT Docomo's tests show that placing an iPhone 17 in the pocket of a VoltCore jacket adds about 18 percent of battery per hour. That pace is slower than wired fast charging, but the advantage is continuous trickle charging throughout the day. After eight hours of work in VoltCore clothing, the phone can stay topped up.

Durability of the fabric itself is the biggest technical challenge. Toray's Materials Research Lab developed a special encapsulation process that seals the copper coils inside a polymer layer. This lets VoltCore fabric survive more than 50 machine wash cycles without significant loss of charging performance. Toray CEO Akihiro Nikkaku said it was the most challenging materials engineering project the company has tackled in the past decade.

On applications, VoltCore's first market is outdoor workers. Japan's largest construction company Taisei has ordered the first 12,000 VoltCore work uniforms for use by site crews. Construction workers no longer need to break off work to charge their phones, and they can keep AR-assisted devices running through the workday.

On the consumer side, NTT Docomo is pricing VoltCore jackets at 39,800 yen, about 270 dollars. The first batch of styles includes business jackets, sports jackets, and work jackets, each with charging-optimized zones tailored to common devices.

VoltCore's safety design is also rigorous. The charging magnetic field is tightly confined to within 15 centimeters of the garment surface, limiting external exposure. Toray's radiation tests show the magnetic field from a VoltCore jacket is only 1/200th the strength of a phone's transmission signal, far below the safety limits set by the International Commission on Non-Ionizing Radiation Protection.

On technology evolution, Docomo and Toray plan to release a second-generation VoltCore in the second half of 2026, lifting charging power from the current 5 W to 15 W. The upgrade will shorten the time needed to fully charge a phone and support simultaneous charging for multiple devices.