Samsung may be testing the giant phone battery upgrade of your dreams — but don't expect much of a boost for the Galaxy S26 Ultra

Samsung Galaxy S25 Ultra Review.

• Samsung is reportedly testing a 20,000 mAh phone battery
• The capacity boost is courtesy of a silicon-carbon compound
• It's unlikely to be ready in time for the Galaxy S26 series

Battery capacity is one of the key specs that most of us look for when buying one of the best smartphones, and Samsung is rumored to be working on a substantial upgrade in this department – although it won't arrive in time for its next flagship phones.