I’m not sure if that is technically correct, but I use a powerbank to power my full size QC, which is also 12v, and it works perfectly - and perhaps more important, SILENTLY, which is not always the case with the factory power supply!
There are lots of threads about this on the forums here, see here;
https://unity.neuraldsp.com/t/my-battery-powered-quad-cortex/12974/34?u=littlespaceman
You’ll need a PD to DC 12v power cable;
and a 2.1mm x 5.5mm polarity reverser. There are lots out there that are in cable form, I really like these as they are a simple and short solid plug, and you can fasten it to the PD to DC power cable using heat shrink, so it’s locked in place;
https://www.amazon.co.uk/Polarity-Changer-Centre-Positive-Negative/dp/B0CKTC6XD9?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A26Q0OBH283CLI
This is a great mobile set up that gives me about 5-6 hours running my QC. Newer full size QC’s may last longer as they have a lower power comsumption.
And I don’t know for sure if the Mini can run this way, but I strongly suspect it can…