Samsung SDI has been conducting tests on silicon-carbon batteries with capacities of 12,000mAh, 18,000mAh, and 20,000mAh. Recent leaks from internal test reports on X reveal that there are still improvements needed for these models.
While no details have emerged regarding the 20,000mAh battery, the reports indicate that the 12,000mAh and 18,000mAh batteries failed after 960 charge cycles, which is not acceptable for performance standards. Both smaller batteries are designed to achieve 1,500 charge cycles, though this is still under evaluation.
The 12,000mAh battery, designated SDI-DC12K-SiC-V2, features a dual-cell configuration with one cell rated at 6,800mAh and measuring 4.7mm, and another at 5,200mAh and 3.2mm. The expected stack thickness is under 9.3mm; however, 2 out of 7 samples exceeded this measurement.
The 18,000mAh battery, known as SDI-TC18K-SiC, is a triple-cell design comprising a 6,699mAh cell at 4.2mm, a 6,000mAh cell at 3.9mm, and a 5,257mAh cell at 3.28mm. The target stack thickness is approximately 12.3mm, but the presence of thermal interface layers has resulted in some samples measuring 12.8mm.
Test reports for Samsung SDI's 12,000mAh and 18,000mAh Silicon-Carbon batteries
The test findings suggest that Samsung SDI is exploring redesign options for the layers and stacking of the cells, alongside improvements to the battery management firmware.
The 12,000mAh battery is estimated to provide between 20 to 25 hours of screen-on time when connected over 4G and Wi-Fi, focusing on stability. Conversely, the 18,000mAh variant prioritizes high capacity and endurance.
There is keen interest in seeing these silicon-carbon cells utilized independently, particularly the 6,800mAh 4.7mm or the 6,699mAh 4.2mm cells for flagship devices. Rumors initially suggested that the Galaxy S26 Ultra would feature a silicon-carbon battery, but this has not materialized. It is hoped that Samsung SDI will complete its testing in time for the launch of the S27 Ultra, with foldable devices also poised to benefit from such thin, high-capacity batteries.
Source | Via
