Disposable vapes are indefensible. Many, or maybe most, of them contain rechargeable lithium-ion batteries, but manufacturers prefer to sell new ones.
To make a point about how wasteful this practice is—and to also make a pretty rad project and video—Chris Doel took 130 disposable vape batteries (the bigger “3,500 puff” types with model 20400 cells) found littered at a music festival and converted them into a 48-volt, 1,500-watt e-bike battery, one that powered an e-bike with almost no pedaling more than 20 miles. You can see the whole build and watch Doel zoom along trails on his YouTube video.
You totally can. I don’t know exactly what the laws are because it’s intentionally not clear but it’s the same process as before, order from a diy website, it comes in the mail, make your stuff at home. I think the difference is that it’s harder for websites to get the license to sell it but there are still some sites out there.