When I saw the headline I was hoping someone had hacked the qualcomm modem and turned it into a software defined radio.
Power tool batteries, eg a dewalt 18v drill, allow a max discharge current of around 10 amps. So for a 600 watt hair dryer, you're going to need 3 power tool batteries! Imagine the cost/weight of that!
To make it work without the high cost/weight, you're going to have to blow mostly cold air and hope the user is okay with that.
The clickbait part is the "Turn your Android phone" bit. Of course you can turn your Android phone into <x>, where <x> is a USB-powered device, for approximately the price of <X>.
Also most drivers won't really use that many charge cycles per day or whatever. I easily use like 90%+ of my phone's battery every day, I'll use up most of my laptop's battery when I'm on the go. Both of these devices often sit at a high state of charge and goose the voltages more to get more juice out of the pack at the expense of how many cycles they're good for. Meanwhile it's not like I'm driving >200mi every day.
If anybody could do that, that would be a nightmare I suppose.
Unfortunately, in a locked down production phone, those modes are unavailable.