Well, Stellatech has them "on request" : https://stellatech.com/en/nokia-lumi...a,811567.html/ .

I have what seems to be an authentic N9 battery which I got new off of eBay and with which I've been trying to unbrick my N9 and the battery seems to charge fine and hold its charge. I bought it from a USA seller -- beware of anything from China or Hong Kong that's Nokia N9 related because most of the items you'll find are counterfeits.

jdb2