Samsung Evaluates Si-C Battery Tech for Galaxy S27 Ultra

Samsung is considering plans to adopt silicon-carbon battery technology across its flagship slab smartphones, including the Galaxy S27 Ultra.

The technology made its commercial debut in the company's latest foldable device lineup. The Galaxy Z Fold8 Ultra incorporates a silicon-carbon anode cell that holds 5,000mAh of energy within a 4.1mm chassis, providing a 14 percent capacity increase over its predecessor.

Company officials confirmed the technical rollout during briefings reported by Seoul Economic Daily.

"The new products introduced a 'silicon-carbon' anode material for the first time to increase energy density," Moon, a Samsung Electronics official, told Seoul Economic Daily.

Moon confirmed that Samsung is evaluating the technology for future conventional phone models.

"For bar-type smartphones, we plan to apply the technology depending on the product, if it benefits the customer experience," Moon said.

Silicon-carbon anode materials replace standard graphite in negative electrodes. Silicon stores up to ten times more lithium ions by volume than graphite, enabling higher energy density in smaller physical spaces.

Pure silicon expands during charge cycles, leading to structural instability if unmanaged. Samsung redesigned the cathode, electrolyte, and separator components to prevent battery swelling.

"Silicon-carbon has the drawback of being chemically highly reactive, so securing stability is essential," Moon explained.

"This means the battery could swell as charging and discharging are repeated," Moon added.

The company added specialized coating and doping to the cathode to handle high-voltage operation. Electrolyte additives form a film over the anode surface to suppress chemical reactivity, and a high-porosity separator allows free ion movement.

Chinese phone makers including Oppo and OnePlus implemented silicon-carbon (Si-C) batteries in flagship devices during earlier product cycles, pushing cell capacities past 7,000mAh. Samsung moved slowly due to strict internal safety protocols established after previous hardware battery recalls.

Samsung officials emphasized that safety testing guides deployment decisions across mass-market devices.

"It must meet Samsung Electronics' own rigorous standards," Moon stated.

"We plan to actively apply the silicon-carbon anode material where needed," Moon added.

New display architecture helped create internal volume for the battery cells in current foldables. A titanium support structure beneath the OLED panel reduced display module thickness by over 10 percent, freeing internal space.

Samsung also modified its charging architecture. Instead of routing current through a primary battery into a secondary cell, the system controls two separate battery paths independently.

"We did not simply pursue a higher charging wattage in numerical terms, but optimized the charging path to match the battery structure and internal design," Moon said.

"Rather than directly charging the main battery and then continuing with indirect charging via the sub-battery, we changed to a structure that independently controls the two battery paths," Moon further explained.

Samsung has used 5,000mAh batteries in its top-tier Ultra models for six consecutive product generations. Internal testing will determine whether the Galaxy S27 Ultra receives the silicon-carbon upgrade ahead of its expected early 2027 release.