An anonymous reader quotes a report from IEEE Spectrum: Busan-based firm Jenax has spent the past few years developing J.Flex, an advanced lithium-ion battery that is ultra-thin, flexible, and rechargeable. With the arrival of so many wearable gadgets, phones with flexible displays, and other portable gizmos, "we're now interacting with machines on a different level from what we did before," says EJ Shin, head of strategic planning at Jenax. "What we're doing at Jenax is putting batteries into locations where they couldn't be before," says Shin. Her firm demonstrated some of those new possibilities last week at CES 2020 in Las Vegas. The devices shown by Jenax included a sensor-lined football helmet developed by UK-based firm HP1 Technologies to measure pressure and force of impact; a medical sensor patch designed in France that will be embedded in clothing to monitor a wearer's heart rate; and wearable power banks in the form of belts and bracelets for patients who must continuously be hooked up to medical devices. To make batteries flexible, companies play around with the components of a battery cell, namely the cathode, anode, electrolyte, and membrane separator. In the case of Jenax, which has more than 100 patents protecting its battery technology, Shin says the secret to its flexibility lies in "a combination of materials, polymer electrolyte, and the know-how developed over the years." J.Flex is made from graphite and lithium cobalt oxide, but its exact composition and architecture remains a secret. "J.Flex can be as thin as 0.5 millimeters (suitable for sensors), and as tiny as 20 by 20 millimeters (mm) or as large as 200 by 200 mm," the report adds. "Its operating voltage is between 3 and 4.25 volts. Depending on the size, battery capacity varies from 10 milliampere-hours to 5 ampere-hours, with close to 90 percent of this capacity remaining after 1,000 charge-discharge cycles. Each charge typically takes an hour. J. Flex's battery life depends on how it's used, Shin says -- a single charge can last for a month in a sensor, but wouldn't last that long if the battery was powering a display."Read more of this story at Slashdot. Click here to read full news..