Samsung may be developing massive 12,000mAh and 18,000mAh phone batteries

Samsung may be testing new smartphone batteries with much higher capacities using silicon-carbon technology. Leaked testing reports suggest the company is currently evaluating 12,000mAh and 18,000mAh battery prototypes as part of its ongoing development work. Also Read: Samsung Galaxy S25 Ultra gets massive discount on Amazon: How to get it for under Rs 60,000

Details about these tests were shared in posts on X by users including Schrödinger (@phonefuturist). The posts claim to reference internal testing notes linked to Samsung SDI. While Samsung has not commented on the development, the leak gives a look at the type of batteries currently being tested. Also Read: Samsung’s glasses-free Odyssey 3D gaming monitors to get 120+ games support by year end

What the leaked reports say

According to the leaked information, Samsung SDI has been experimenting with several silicon-carbon battery configurations, including 12,000mAh, 18,000mAh and even a 20,000mAh prototype.

However, the reports claim the larger 20,000mAh battery did not meet durability targets during testing. The prototype reportedly failed after around 960 charge cycles, which is below the company’s expected lifespan for smartphone batteries.

Samsung is therefore continuing development with the 12,000mAh and 18,000mAh designs while working to improve reliability and thermal performance.

Details of the 12,000mAh battery prototype

One of the prototypes mentioned in the report is a 12,000mAh silicon-carbon battery (SDI-DC12K-SiC-V2) built using a dual-cell structure. It reportedly combines a 6,800mAh cell with a thickness of about 4.7mm and a second 5,200mAh cell measuring roughly 3.2mm.

The intended combined stack thickness is said to be under 9.3mm. However, some of the tested samples reportedly ended up slightly thicker than expected during early testing.

The 12,000mAh design is said to prioritise stability. Internal estimates mentioned in the report suggest such a battery could deliver roughly 20 to 25 hours of screen-on time in a smartphone connected to both mobile data and Wi-Fi.

The 18,000mAh triple-cell design

Samsung is also testing a larger 18,000mAh configuration (SDI-TC18K-SiC) using a triple-cell setup. According to the leak, the design combines three cells rated at 6,699mAh, 6,000mAh and 5,257mAh.

The goal is to keep the stacked battery thickness around 12.3mm. However, additional thermal interface layers used between the cells reportedly pushed some test units to around 12.8mm.

Why Samsung is exploring silicon-carbon batteries

Silicon-carbon batteries are designed to store more energy than traditional lithium-ion batteries. Instead of the usual graphite, the Si-C batteries use silicon-based anodes, which can help bump up the capacity without making the unit much larger.

Add Techlusive as a Preferred Source

Several Chinese smartphone brands have already adopted silicon-carbon batteries in their devices. Samsung, however, appears to be moving more carefully. The company is said to be still working on improving durability, battery management systems, and how the cells are stacked before introducing the technology in commercial smartphones.