TECH NEWS – The South Korean tech giant encountered problems during testing and is preparing to use lower-capacity batteries in its future smartphones.

Since the 2016 Samsung Note 7 fiasco, the company has taken a relatively conservative approach to battery technology. However, this cautiousness is now proving costly, as Chinese OEMs are taking the lead in giant silicon-carbon (Si/C) battery technology. Samsung SDI’s initial efforts to catch up with competitors in this area have largely failed, prompting the battery division to focus on more modest 6,000–8,000-mAh silicon-carbon batteries.

Recently, we heard that Samsung SDI is testing a 20,000-mAh dual-cell silicon-carbon battery. The primary cell has a capacity of 12,000 mAh and is 6.3 mm thick; the secondary cell has a capacity of 8,000 mAh and is 4 mm thick. However, during testing, the primary 12,000-mAh cell exhibited stability issues, resulting in a significant drop in yield and mechanical swelling. The cell reportedly swelled from 6.3 mm to 8.2 mm, increasing the total thickness of the dual-cell battery to 14 mm, nearly as thick as the outer casing. The cell was reportedly charged at a rate of 100 W.

Samsung SDI Scales Back 12,000 mAh Battery Push, Refocuses on 6,000–8,000 mAh Si/C Cells and Solid-State Futurehttps://t.co/rqNOGF0dZO pic.twitter.com/XHNG6WoDFE

— Schrödinger (@phonefuturist) December 30, 2025

Samsung’s ultimate goal was to develop a 12,000-mAh single-cell battery. Multi-cell batteries require more insulation to prevent short circuits between cells. Single-cell batteries are orders of magnitude more efficient but harder to stabilize at higher energy densities. Samsung SDI’s apparent failure with the 12,000-mAh cell has reportedly prompted the company to focus its efforts on smaller 6,000–8,000-mAh silicon-carbon batteries, which showed greater yield consistency and more predictable volume expansion in early testing. Samsung SDI is also working on solid-state batteries in parallel.

Silicon-carbon batteries differ from conventional lithium-ion batteries because the anode is not graphite but a break-resistant, nanostructured silicon-carbon composite. This allows the anode to store up to ten times more lithium ions, dramatically increasing capacity while keeping the battery very thin.

Source: WCCFTech