The battery in the HP Prime is compatible with the battery for the Samsung Galaxy S3 cell phone. The only caveat is that it's NOT the double-thickness, double-capacity battery which is so fat that it can only be used in a Galaxy S3 by replacing the back cover with a fatter one. Those fatter batteries cannot be used with Prime at all, even with the battery cover left off, because the electrical contacts are on the wrong side. So just get a normal Galaxy S3 cell phone replacement battery, and it'll work great in your Prime. They are widely available, made by many different companies (not just Samsung).
In this photo, the CORRECT battery is on the left. The WRONG (too-fat) battery is on the right: