Personally, I would not recommend diving into Linux headfirst by installing it as your only operating system. If you can afford an additional small drive (128GB should be plenty), I would suggest buying one and installing something like Linux Mint on that, while putting Windows on your main drive.
That way, you can switch between them whenever you want to (when you turn on your computer, you can just use a menu to choose which drive to boot to), and get somewhat familiar with Linux before deciding if it’s worth your time to really dive in.
(There’s a way to put both operating systems on the same drive, but it’s really easy for something to go wrong and end up with one of the operating systems inaccessible. Since you’re inexperienced, I would avoid going that route for the time being, and just keep both on separate drives.)
It boils down to chemistry. The nickle-metal-hydride chemistry used in rechargeable batteries just don’t produce 1.5V (explaining why is a lot more complicated), while the alkaline chemistry in non-rechargable batteries produces slightly more volts.In the same vein, lithium-ion batteries produce around 3.6V, while lead-acid produce about 12.4V.
To answer your other question, they should be able to power most things that aren’t an analog clock (which might run slightly slow).