The world is no stranger to flexible batteries, but they've almost always had to be made in thin sheets -- that doesn't amount to a long running time if you're powering anything more than a watch. LG Chem has developed a flexible lithium-ion battery that's not just better-suited to our bigger gadgets but could out-do previous bendable energy packs. Researchers found that coating copper wires with nickel-tin and coiling them briefly around a rod results in a hollow anode that behaves like a very strong spring; mating that anode with a lithium-ion cell leads to a battery that works even when it's twisted up in knots. Join multiple packs together, and devices could have lithium-ion batteries that fit many shapes without compromising on their maximum deliverable power. Some hurdles remain to creating a production-grade battery, such as a tendency for the pack to shed a small amount of capacity whenever it's put under enough stress. LG Chem is fully set on turning these cable batteries into shippable technology, however, and could ultimately produce mobile devices and wearables that really do bend to their owners' every whim.