Do phone batteries last longer when it’s cooler outside?

You might think so — but the answer is not always. Smartphones use lithium-ion batteries. This battery works by moving lithium ions back and forth between two electrodes through a liquid electrolyte.

In colder weather, like in North India during the winter, the electrolyte becomes less conductive and the lithium ions move more sluggishly. The battery’s internal resistance also increases. As a result, the voltage can drop faster if you use the phone heavily. Your phone might interpret this drop as low battery and trigger power-saving measures even when the battery has more charge.

In hot weather, like a typical Indian summer, the battery chemistry becomes more active and can deliver power easily. But heat also speeds up unwanted chemical reactions, which over time permanently reduce the battery’s capacity and shorten its lifespan.

This is why your smartphone constantly monitors the battery temperature. If the battery gets too hot due to fast charging, gaming, direct sunlight, and/or a bad phone cover, the phone may stop charging as a safety measure. At sufficiently high temperatures, in fact, lithium can get deposited as metallic lithium on the electrode, creating conditions that could even lead the battery to fail.

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