Hi,
On Polish auction service Allegro it's possible to buy original battery (it looks like original) for Jolla JP-1301. It's cheap, it costs 5EUR.
http://allegro.pl/nowa-oryginalna-ba...649316614.html
Seller has 47 batteries.

If someone need spare battery and need help (site is in Polish or need ship abroad) I can help with that.
I have to admit I don't know the seller so I can't guarantee it's original. One Polish guy have bought it and said it looks and work like original.
https://together.jolla.com/question/...tery-for-sale/