No one is using a little sticker hidden on your battery to spy on you, no matter what Facebook tells you.
It's easy to get confused by the inside of a smartphone, even if you're reasonably familiar with a lot of the technology that goes in to these devices. NFC chips are particularly curious, as their size makes it easy to sneak them in just about anywhere, and most folks outside of the tech bubble have no idea what NFC is or why we need the tech on our phones. In fact, all it would take to get someone worried about NFC is a reasonable-ish theory about government surveillance and a narrative that suggests the technology is being hidden from you somehow.
That's exactly what is happening on Facebook right now, thanks to a video making the rounds detailing a "disturbing discovery" under a Samsung battery.
It's the sort of thing those of us who know better are likely to laugh off and get back to work, but the current conversation surrounding government surveillance makes it easy for something like this to spread like wildfire. NFC chips are regularly sealed in plastic on the backs of phones or, in Samsung's case, baked right into the battery so you were more likely to buy a Samsung-made battery when the need arose. Unfortunately, this is one of those things that aren't widely understood — because why would you — and craziness ensues.
So please, don't try to pull the sticker off of your Samsung battery. Don't let anyone you know try it either, the risk for accidentally puncturing your battery is just too high. That chip is not harvesting your data in any way, and can actually be used for some really cool things if you know how. It'd be a lot more fun to give some of those things a try.