Sony VTC5 18650 Battery

You can store them for 1.5 years at -30 to + 25 degrees C, 3 months at 30 to 45 C and 1 month at 30 to 60 C (in other words, store them in a cool place and they'll last longer)

(Equivalent may be supplied) 

Specs:

Nominal Capacity: 2600mAh
Rated Capacity: 2500mAh
Max Continuous Discharge Current: 20A
Nominal Voltage: 3.6V/3.7V
Full charge Voltage: 4.2V
Internal Impedance 13 mΩ measured by AC 1kHz
Operating Temperature (cell surface): Charge 0 ~ 50? , Discharge -20 ~ 75
Diameter 18.45mm max +/- 0.05mm
Length 65.20mm max +/- 0.05mm
Weight : 44 g Average
Positive terminal: Flat top
Battery Type / shape: 18650 Cylindrical