Samsung has been under pressure on battery capacity for a while now. The Galaxy S26 Ultra launched earlier this year with a 5,000mAh cell . That’s the same capacity it shipped in the S20 Ultra back in 2020. Meanwhile, Chinese brands like OnePlus and Xiaomi have been fitting 7,000mAh and larger silicon carbon batteries into slim flagships. According to leaked documents, Samsung SDI may finally be working to close that gap in a very big way. According to a post on Schrodinger Intel , they posted what appear to be internal Samsung SDI test documents, revealing the company is reportedly testing silicon carbon battery cells at 12,000mAh, 18,000mAh, and 20,000mAh capacities. Those are not typos. For context, the OnePlus Ace 6 Ultra just launched with an 8,600mAh battery, and that’s considered enormous by current standards. Samsung silicon carbon battery testing still has hurdles The leaked documents suggest the 12,000mAh design uses two stacked cells: a 6,800mAh cell at 4.7mm and a 5,200mAh cell at 3.2mm.…