[Jay Kickliter] built his own coin cell battery recharger. This won’t work on the vast majority of coin cells as they are manufactured as disposable parts. But there are rechargeable options out ...

The ring itself is in two parts: a base, and a cover to diffuse and protect the LEDs. A pair of wires run out from the ring and connect to a printed coin cell holder.

The experts used a coin cell battery for the test ... The goal is often to find better-performing, less expensive parts. The Korean work also addresses key environmental and health concerns.