Is Samsung Testing a 20,000mAh Dual-Cell Silicon-Carbon Battery?

Highlights

• Samsung SDI is rumoured to be testing a 20,000mAh dual-cell silicon–carbon battery.
• Internal tests reportedly showed 27 hours of screen-on time and nearly 960 charge cycles annually, though it reportedly faced swelling issues.
• There is a possibility that the battery may be evaluated for larger applications like electric vehicles.

Samsung is reportedly testing a 20,000mAh battery. (Image credit – Unknown)

For Chinese smartphone brands, 7,000mAh is the new 5,000mAh battery capacity today. Brands have recently started shipping with batteries as large as 8,000mAh or more. In short, they have made it the standard specs for mid-to-high-end smartphones. However, some big brands outside of China often seem hesitant when it comes to battery capacity, even for flagship phones. Samsung is one such brand.

The Korean company has traditionally been conservative with battery sizes in its smartphones. Even the company’s latest flagship namely the Galaxy S25 Ultra features a 5,000mAh battery. But the latest word suggests this could change soon.

A new rumour suggests that Samsung SDI may be experimenting with an even bigger battery, potentially pushing capacities to an entirely new level.

According to X user Schrödinger @phonefuturist, Samsung SDI is currently testing a massive 20,000mAh dual-cell silicon–carbon battery.

The leak claims that the experimental battery uses a dual-cell design, combining a 12,000mAh cell with a thickness of 6.3mm and an 8,000mAh cell measuring 4mm thick. During internal testing, the battery reportedly delivered around 27 hours of screen-on time and achieved close to 960 charge cycles annually, which would be impressive figures if accurate.

Images of swelled battery surfaces on X.

However, the testing reportedly raised concerns. According to the same source, the battery began to show signs of swelling shortly after the tests were completed, pointing to potential long-term durability issues. Another tipster added that the 8,000mAh cell alone expanded from its original 4mm thickness to about 7.2mm after swelling. The tipster also posted some pictures to support the claim.

While we couldn’t verify this claim, there is also a possibility that Samsung SDI is evaluating this large-capacity battery for applications beyond smartphones such as electric vehicles. It remains unclear whether such technology will ever make its way into consumer smartphones.

FAQs

Q1. What type of battery is Samsung reportedly testing?

Answer. Samsung SDI is said to be experimenting with a massive 20,000mAh dual-cell silicon–carbon battery.

Q2. How is the dual-cell battery Samsung reportedly designed?

Answer. It combines a 12,000mAh cell (6.3mm thick) with an 8,000mAh cell (4mm thick) to reach the total capacity.

Q3. What issues were observed during Samsung 20,000mAh battery testing?

Answer. Reports claim the battery showed swelling, with the 8,000mAh cell expanding from 4mm to about 7.2mm, raising durability concerns.

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