After many years of good service, my mini printer was not able to print a full picture anymore. Its battery was done, and could not even hold enough charge to go through one full print.
Instead of buying a new one and create e-waste, I chose to replace its battery. It was pretty challenging to find a battery pack that would replace properly the one originally present in the device.
This guide should also work other Zink mini printer like the Canon IVY mini photo printer or the HP sprocket mini photo printer line.