Efforts to improve smartphone battery technology are continuing and in this context, Samsung’s battery unit Samsung SDI is working on new high capacity batteries. A recently leaked report has claimed that the company is testing Silicon Carbon batteries with 12,000mAh, 18,000mAh and 20,000mAh capacity. These internal test reports have surfaced on social media platform X. However, the report also indicates that the company will have to work on some technical challenges before these batteries are ready for the market.
According to test reports leaked by a user on X, Samsung SDI is currently doing detailed testing of 12,000mAh and 18,000mAh Silicon Carbon batteries. It has been told that these batteries failed the test after about 960 charge cycles. Whereas the company aims to deliver battery life up to about 1,500 charge cycles. Therefore, it is believed that the company is currently working on improving their design and technology.
According to test reports, the model of the 12,000mAh battery is said to be SDI DC12K SiC V2. It comes with a dual cell design, which includes a 6,800mAh cell with 4.7mm thickness and another 5,200mAh cell with 3.2mm thickness. The company aims to keep its total stack thickness under 9.3mm, although some units in the test samples were found to be slightly thicker than this limit.
Samsung SDI is testing 12K, 18K mAh Si/C cells. The 20K failed at 960 cycles. Race is on. 👀
Full PDF available, Samsung tracking system didn’t work much. Anyways it’s not free. pic.twitter.com/D8NDy4weNw
— Schrödinger (@phonefuturist) March 9, 2026
The 18,000mAh battery has been named SDI TC18K SiC and triple cell design has been used in it. It includes three different cells with capacities of 6,699mAh, 6,000mAh and 5,257mAh. The thickness of these three cells is said to be 4.2mm, 3.9mm and 3.28mm respectively. The target stack thickness of this battery was kept at about 12.3mm, but due to the thermal layer used between the cells, the test samples were found to be about 12.8mm thick.
The report says that Samsung SDI is now working on making changes to the cell layer and stacking design of the battery. Along with this, efforts are also being made to improve the battery management firmware so that the performance and life cycle of the battery can be improved.
According to the company’s test notes, the 12,000mAh battery is being designed for stability and long usage. It is estimated that this battery can provide about 20 to 25 hours of screen on time in the smartphone with 4G and Wi Fi connection. The focus of the 18,000mAh battery has been kept on high capacity and long battery backup.
At present, these batteries are in the initial stage of testing and no official information has been revealed by the company regarding using them in any particular smartphone. However, reports believe that in the future, high capacity and thin Silicon Carbon batteries can be used in flagship smartphones and foldable devices.
