Horsesh*t. It's not the speed of the charging that hurts batteries. It's overcharging (charging after battery reaches 100%) and running your device too hot, for too long. Those are the 2 most common battery life killers. Set your apps/widgets/notifications on your phone to warn your device is fully charged, so you know to unplug it to avoid overcharging. Also do not plug it in before bed (phone will hit full charge before the night is even half over) Instead, charge up BEFORE bedtime. Then plug in while you get ready in the morning, if you need battery level higher by the time you leave. Also, use apps/widgets/notifications to warn you if internal temperature is getting too high. I always try to make sure my smartphone runs well under 100°F.