Will iphone powerbank break if not used frequently?

I have a powerbank and i'm saving it for emergencies but if I don't use it like frequently will it break!

I will not break, but it will become less effective, I will assume that it is a Li-On battery and I electrons need to be kept moving (using the battery) at least once a month.
If you don't use it at least each month, it won't break but it will slowly become less effective, also if you are not going to use the battery for a long time store it at around 50% charge.

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