Samsung's ambitious 20,000 mAh silicon-carbon smartphone battery faces swelling hurdles

Samsung may be preparing a sharp jump in smartphone endurance, though serious technical hurdles stand in the way. According to insiders, Samsung SDI is testing an experimental 20,000 mAh battery designed for mobile devices and based on silicon–carbon technology.

Reports suggest the pack uses a dual-cell layout with differently sized elements. One module is said to hold 12,000 mAh at roughly 6.3 mm thick, while the second adds another 8,000 mAh at about 4 mm. Together, the configuration reaches a striking 20,000 mAh—twice the capacity that until recently sat at the extreme end for phones.

Even the single 12,000 mAh cell already surpasses the 10,000 mAh batteries found in models like the Honor Win, hinting at how ambitious Samsung’s target is. Preliminary estimates indicate the full pack could deliver up to 27 hours of active screen time and endure around 960 charge cycles a year.

There is, however, a significant catch. Sources say the battery ran into swelling during tests, raising questions about longevity and safety. In particular, the smaller 8,000 mAh cell reportedly expanded from 4 to 7.2 mm—an unacceptable figure for slim mobile devices.

So while Samsung may be closing in on Chinese manufacturers in the race for ultra-high-capacity batteries, the current solutions still look decidedly experimental. On paper, the numbers impress; in practice, stability and reliability will decide if and when such a pack reaches mass-produced smartphones. The appetite for bigger batteries is obvious, yet it’s thermal limits and safety margins—not headline capacities—that ultimately set the pace.