It's less dangerous, but some of the flammability is inherent in the chemicals withing the battery, and how they'll react to oxygen or water. Let's say that yo

It's less dangerous, but some of the flammability is inherent in the chemicals withing the battery, and how they'll react to oxygen or water. Let's say that you were able to magically disassemble a cellphone battery into its constituent elements and compounds, made rods out of each, and then sealed each rod in a zip-lock bag in a vacuum chamber. The resulting collection of zip-lock bags is still something you wouldn't want to keep on a shelf somewhere, e.g. https://youtu.be/Vxqe_ZOwsHs https://youtu.be/Vxqe_ZOwsHs shows how elemental lithium reacts.