The Times asks, Should you charge your phone overnight? The answer is obviously no. I mean, yes. Or, maybe.
As the Times points out, your phone won’t overcharge. No harm there.
But, but, but... all charging “harms” your phone. Which is both alarming and useless. What am I supposed to do? Not charge it? That’s not very useful. But apparently I can charge it if I’m replacing it in two years, which sounds like it has the cause and effect somewhat reversed. Nor does it provide me with a plan if I intend to keep it.
Finally, the article drops a hint that the real issue is that fast charging pushes a lot of current into the battery, which may shorten the lifespan. This makes some sense as I understand battery chemistry. Their suggestion to use a lower rated charger seems pretty weak however. It may work, but it’s haphazard.
Keep in mind that I am not an officially licensed li-ion whisperer.
Modern chargers switch between constant current (when the battery is low) and constant voltage (when the battery is nearing full). Refer to AnandTech charge graph.
If we want to avoid the damaging high current charging, then we should aim to charge our phones frequently, topping them up with low current charging. I believe the Times article misleadingly suggests minimizing the number of charges; i.e., letting it run down and then charging, which would actually result in the most exposure to high current charging.