Where can you find Samsung replacement batteries?

Replacement Samsung batteries for devices with replaceable batteries can be purchased from https://www.storebattery.co.nz, as well as other electronics retailers.
We recommend that spare batteries are kept in a hard-shell case when not in use. You should use only batteries manufactured by Samsung or batteries that have been otherwise approved by Samsung for use with Samsung products.(source from www.samsung.com)

samsung aa-pbun2tp battery

Also original brand new samsung aa-pbun2tp battery 7.6V 4400mAh is just on market now. This is 100% genuine Samsung battery, battery cost is N$85.29 (Including taxes).
Voltage: 7.6V
Capacity: 4400mAh (33Wh)
Battery cells: 2-cell
Chemical: Li-ion
Battery Color: white
Condition: new original battery
Warranty: 9 months