Samsung adopts silicon-carbon battery to improve capacity for new foldables

Samsung Electronics Executive Vice President at Mobile R&D Office Moon Sung-hoon speaks during a press briefing on the sidelines of Galaxy Unpacked 2026 in London, Thursday (local time). Courtesy of Samsung Electronics

LONDON — Samsung Electronics has adopted silicon-carbon anode batteries for the Galaxy Z8 foldable smartphone series unveiled at the Galaxy Unpacked 2026 event here and is considering expanding the technology to the Galaxy S27 series.

During a press briefing on Thursday, Samsung Electronics Executive Vice President at Mobile R&D Office Moon Sung-hoon said the Galaxy Z8 series for the first time used silicon-carbon battery to improve energy density within the same amount of space.

Silicon-carbon anodes significantly increase energy density compared to conventional batteries using graphite anodes. By adopting silicon-carbon anode, the Galaxy Z Fold8 Ultra is equipped with a 5,000 milliampere-hour pack, 14 percent larger than that of its predecessor, while maintaining a record-thin profile of 4.1 millimeters.

Chinese smartphone makers have been using silicon-carbon for their smartphone batteries, but Moon said Samsung decided to adopt the technology only after it met the company's stringent safety standards, given the material's structural drawbacks.

"Silicon batteries have the advantage of increasing battery capacity within the same volume, but the material is highly reactive, meaning it can expand and contract repeatedly during charging and discharging," Moon said.

"To improve safety, we changed the entire battery system, including the anode, cathode and separator, to find the optimal combination. We adopted the technology only after evaluating it under a wide range of scenarios and confirming that it met our strong safety standards."

He added that the company could adopt silicon-carbon batteries for the Galaxy S series, its bar-type smartphones, if the technology helps improve customer experience.

The new foldables are also the first in the series to support up to 45-watt super-fast charging. The Galaxy Z Fold8 Ultra can charge its battery to about 67 percent in just 30 minutes.

A model promotes Samsung Electronics' Galaxy Z Fold 8 Ultra, Flip 8, Fold 8 smartphones at the company's showroom in Seocho District, Seoul, Thursday. Yonhap

Along with the new battery material, the company also used titanium in the displays of the new foldables for the first time to secure more space for the battery and significantly reduce the crease.

Dubbed Flex Titanium, it is a combination of titanium plate to support the display and a titanium alloy film that replaces the conventional plastic film beneath the OLED panel to increase rigidity.

The titanium alloy film is an advanced material made by processing titanium alloys containing vanadium, aluminum and chromium into an ultra-thin film about one-third the thickness of a human hair strand, followed by heat treatment to withstand repeated folding.

The technology makes the display module more than 10 percent thinner, allowing the extra space to be used for a larger battery.

"The titanium alloy film supports the crease area from underneath, minimizing sagging,” Moon said. "The titanium plate and alloy film work together to improve the folding experience and durability."

Moon noted reducing the thickness by 0.1 millimeter cannot be achieved by redesigning a single component. Every element, including the display, reinforcement materials and the battery, must be considered together to facilitate the improvement.

"No matter how advanced the materials and design are, all our efforts are meaningless if users do not feel comfortable or confident when using the product," Moon said. "Samsung's vision for foldable smartphones is to deliver overwhelming reliability that can withstand every harsh real-world scenario, and the Galaxy Z8 series is the best embodiment of that vision."