Is it safe to store a battery in the freezer?
Going off your Lifehacker article, a refrigerator will be fine, as it is within the temperature range that is mentioned in the chart, and will probably help some.
With regard to the freezer, I have been unable to find a definitive answer, but I would mention a few points:
- There is no water in a lithium ion battery, so it is highly unlikely that anything interesting will occur at that temperature
- There is very little (comparative benefit) that you can get. Even if you can halve the loss rate by going to whatever your freezer goes to, it is no-where near as big a difference as going from room temperature to a refrigerator (close to 0 C).
Note: While even if in general there is no issue with putting a lithium battery in the freezer, since the amount of charge that it can hold is reduced at very low temperatures, it should not be fully charged when you put it in the freezer. Thank you @BruceConner for pointing it out.