"suitable" is by definition always correct, but perhaps not what you originally thought/meant. See link above.
And 3.7Volts is like you added elsewhere, is the individual volts of the 2 batteries. The charging module and other electrical necessary conversion like technisol pointed at, and also further tech details, are all deciding factors in charging compatibility. Pointing at link above.
As for the battery itself, for those inclined, please see: http://forum.chuwi.com/forum.php ... ight=Battery%2Bhi13