Exactly, good point.I really hope this was meant as a joke. Heating batteries in a microwave is extremely dangerous. Certain components can overheat, expand, and fail, potentially causing short circuits and severe damage to the battery. There’s also an added risk from eddy currents induced by the microwaves, which can create sparks in metallic parts and even start a fire.
On top of that, microwaves only heat certain molecules—mainly water—by resonating with them at about 2.45 GHz. That’s why dry materials like glass stay cool while food heats up quickly. A battery is not designed to absorb energy that way, so the only likely outcome is damage.
In short, please don’t try this. It’s dangerous and serves no useful purpose.
This is why I always pre-soak my battery in the bath to try and absorb as much water as possible to make the microwaving more effective.
Ideally charged water ion's are better, so I normally drop the hairdryer in the bath at the same time for more effective ion flow.