Here's a chart of Li-Po deteriation during stoarge at vaious temps and states of charge. Link - http://www.vapextech.com.hk/product-...kthrough2.html

Storage temperature and charge

Storing a Li-Po battery at the correct temperature and charge makes all the difference in maintaining its storage capacity. The following table shows the amount of permanent capacity loss that will occur after storage at a given charge level and temperature.

It is significantly beneficial to avoid storing a Li-Po battery at full charge. A Li-Po battery stored at 40% charge will last many times longer than one stored at 100% charge, particularly at higher temperatures.
If a Li-Po battery is stored with too low a charge, there is a risk of allowing the charge to drop below the battery's low-voltage threshold, resulting in an unrecoverably dead battery. Once the charge has dropped to this level, recharging it can be dangerous. An internal safety circuit will therefore open to prevent charging, and the battery will be for all practical purposes dead.

In circumstances where a second Li-Po battery is available for a given device, it is recommended that the unused battery be discharged to 40% and placed in the refrigerator or freezer to prolong its shelf life. Batteries should be allowed to completely warm to room temperature over up to 24 hours before any discharge or charge.
Permanent Capacity Loss versus Storage Conditions
Storage Temperature 40% Charge 100% Charge
0 °C (32 °F) 2% loss after 1 year 6% loss after 1 year
25 °C (77 °F) 4% loss after 1 year 20% loss after 1 year
40 °C (104 °F) 15% loss after 1 year 35% loss after 1 year
60 °C (140 °F) 25% loss after 1 year 40% loss after 3 months