March 12, 2026, 8:22 am | Read time: 4 minutes
Even in Samsung’s top smartphones, users have had to settle for 5,000 mAh batteries for years. Other countries are far ahead, installing batteries in their smartphones that offer up to several 10,000 mAh. However, a shift in Samsung’s approach seems to be underway, as the company has started testing innovative silicon-carbon batteries with significantly higher capacity.
The information about the tests comes from internal documents currently circulating on X. They provide insight not only into the current development status but also into the weaknesses that the prototypes still have.
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The trial runs are conducted by Samsung SDI, a subsidiary of the South Korean Samsung Group specializing in the development and production of energy storage systems. The company is one of the key battery suppliers within the Samsung Group and is developing new cell chemistries such as silicon-carbon batteries, which are intended to enable higher energy density. Energy density indicates how much energy can be stored in a given volume—essentially, how much battery capacity can fit into a slim casing.
According to the information from the internal documents, Samsung SDI tested batteries with 12,000 mAh, 18,000 mAh, and 20,000 mAh. The largest variant with 20,000 mAh reportedly showed a defect after about 960 charge cycles during trials. This value is considered insufficient for use in mass-produced devices.
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Challenges with 12,000 and 18,000 mAh
More promising for serial use are the batteries with capacities of 12,000 or 18,000 mAh. Tests are still ongoing for these models. Samsung SDI aims for around 1,500 charge cycles before the capacity drops to 80 percent. Whether these values can be achieved is still uncertain.
The 12,000 mAh battery is designated SDI-DC12K-SiC-V2 and uses a two-cell design. It includes a 6,800 mAh cell with a thickness of 4.7 millimeters and a 5,200 mAh cell with 3.2 millimeters. The total thickness of the module is supposed to remain under 9.3 millimeters, although some test samples have apparently exceeded this value.
The 18,000 mAh model SDI-TC18K-SiC uses three stacked cells: 6,699 mAh at 4.2 millimeters, 6,000 mAh at 3.9 millimeters, and 5,257 mAh at 3.28 millimeters. A construction height of about 12.3 millimeters is planned. However, due to additional heat conduction layers, the current prototypes have reached 12.8 millimeters.
Significantly Longer Run Times for Everyday Tasks
For the 12,000 mAh battery, developers expect a screen time of 20 to 25 hours with active use and 4G and Wi-Fi connection. This variant is designed for stability. The larger 18,000 mAh battery, on the other hand, is primarily aimed at maximum runtime. Due to its height of 12.8 millimeters, it is more suitable for rugged outdoor smartphones than for standard models.
For comparison: In the Galaxy S26 series, Samsung continues to install a maximum of 5,000 mAh. The Galaxy S26 Ultra also has a 5,000 mAh battery. Only the Galaxy Z TriFold exceeds this value with 5,600 mAh, distributed across three segments. While several Chinese manufacturers already use capacities of over 7,000 mAh and more in their flagship models, Samsung remains cautious with regular devices.
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Silicon-Carbon Batteries Compared to Traditional Batteries
Currently, smartphones, tablets, and most other mobile devices predominantly use lithium-ion batteries. These typically feature a graphite anode and liquid electrolyte. The most technically widespread are lithium-ion polymer batteries (Li-Polymer), a form of the traditional lithium-ion battery that can be manufactured particularly flat, making it ideal for slim devices.
Silicon-carbon batteries are still in the development or early introduction phase. Some manufacturers, especially from China, are already partially using silicon in the anode to increase energy density. These batteries replace graphite in the anode entirely or partially with silicon, which can absorb significantly more lithium ions, thereby enabling higher energy density—more capacity in the same volume. However, silicon expands significantly when charging and contracts again when discharging, causing material stress and a shortened lifespan. Silicon-carbon technology promises larger batteries in thinner devices but is technically more challenging and currently less durable than traditional lithium-ion batteries.
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What’s Next After the Tests?
During the Galaxy Unpacked event, Samsung confirmed in discussions with journalists that it is working on silicon batteries. However, deployment will only occur once extensive tests are completed and a clear benefit for users is evident. Currently, production in the required quantities is considered complex, and the lifespan is still shorter than established solutions.
Internal notes indicate that Samsung SDI is working on a revised stacking of the cells and new intermediate layers. Additionally, the battery management firmware is being adjusted. Whether upcoming models like the Galaxy S27 Ultra or the Galaxy Z Fold 8 will benefit from the new technology remains uncertain.