Samsung has adhered to a relatively conservative path when it comes to battery tech ever since the Note 7 fiasco back in 2016. However, this inertia is now costing the South Korean behemoth as Chinese OEMs increasingly take the initiative with monster silicon-carbon (Si/C) batteries.
What's more, the nascent efforts by Samsung SDI - the South Korean behemoth's battery-focused unit - to put up some much-needed competition in this sphere have largely failed, prompting the unit to refocus its efforts towards the more modest 6,000-8,000mAh silicon-carbon batteries.
Samsung SDI's 20,000mAh silicon-carbon battery reportedly entailed stability concerns amid yield degradation and mechanical swelling, prompting a downshift towards 6,000-8,000mAh batteries
We reported recently that Samsung SDI was testing a 20,000mAh dual-cell silicon-carbon battery, where the primary cell had a 12,000mAh capacity and a thickness of 6.3mm, while the secondary cell retained a capacity of 8,000mAh and a thickness of 4mm.
It is the primary 12,000mAh cell, however, that entailed significant stability concern during testing, showing significant yield degradation and mechanical swelling.
In fact, the 12,000mAh cell reportedly swelled from 6.3mm to 8.2 mm, increasing the overall thickness of the 20,000mAh dual-cell battery to 14mm - nearly as thick as the cells' outer housing. The cell was reportedly charged at 100W speeds.
Samsung's end goal was to develop a single-cell, 12,000mAh battery. Do note that batteries with multiple cells require more insulation to prevent the cell from shorting. A single-cell battery is orders of magnitude more efficient, but is harder to stabilize at higher energy densities.
Samsung SDI's apparent failure with the 12,000mAh cell has now reportedly prompted it to refocus its efforts towards a silicon-carbon battery with a smaller 6,000-8,000mAh capacity, which has demonstrated higher yield consistency and a more predictable volumetric expansion metric in early testing. Additionally, Samsung SDI is also working on solid-state batteries in tandem.
As we noted in a dedicated post recently, silicon-carbon (Si/C) batteries differ slightly from conventional lithium-ion ones in their choice of the anode, which is made up of a fracture-resistant, nanostructured silicon-carbon composite material instead of the typical graphite, allowing the anode to hold up to 10x as many lithium ions, essentially increasing the battery's capacity by orders of magnitude, while allowing for a very slim overall form factor for the battery.
About the author: Writing is my one incontrovertible passion. Over the past six years, he has authored over 2,200 distinct articles on financial and tech-related topics, spanning nearly 1 million words. And he has been a member of Wcctech mobile team since 2025. As an alumnus of the University of Toronto, Rotman Commerce Program, I bring nuance, in-depth knowledge, and a unique perspective to every topic that I cover. When I'm not writing, I'm traveling the world, exploring hidden confectionaries and restaurants as an aspiring food connoisseur.
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