“It’s terrible for the environment, but it’s a great source of free lithium cells for our projects.”
Disposable vapes ship with rechargeable 500mAh lithium cells, then get tossed in the gutter after one use. The cells test close to spec and charge to 4.2 volts in about an hour. They have no protection circuit, so you add one. The vape industry is throwing away working batteries by the million while everyone else fights over lithium supply.