We’ve recently seen a surge in smartphones from Chinese brands packing 8,000mAh or larger batteries. Now, a tipster claims that Samsung SDI is testing a massive 20,000mAh dual-cell battery for smartphones.
Samsung isn’t exactly known for pushing battery capacities in its smartphones. Even its latest flagship, the Galaxy S25 Ultra, comes with a 5,000mAh cell. However, according to a tipster, Samsung SDI is currently testing a dual-cell silicon–carbon battery with a massive 20,000mAh capacity.
According to the tipster, the dual-cell setup consists of a 12,000mAh cell measuring 6.3mm in thickness, paired with an 8,000mAh cell that is 4mm thick. During testing, the battery reportedly achieved an impressive 27 hours of screen-on time (SoT) and around 960 annual charge cycles.
That said, the testing reportedly didn’t end well. The battery is said to have developed swelling shortly after the tests concluded, raising concerns about long-term durability. Another tipster adds that the 8,000mAh cell swelled from 4mm to 7.2mm in thickness.
Notably, this information should be taken with a pinch of salt, as it comes from a not-very reliable source. It is also likely that Samsung SDI is testing the battery for electric vehicles instead of smartphones.
