Galaxy Z Fold 8 gives Samsung fans the silicon-carbon battery they've been waiting for

Published Jul 22, 2026, 10:52 AM EDT Andy is a seasoned technology journalist with more than 15 years experience in the mobile industry, writing for Digital Trends, Wired, and more. Andy has reviewed hundreds of smartphones and tablets, dozens of smartwatches, and a host of smart rings, smart glasses, and fitness trackers, giving him a unique ability to assess and evaluate the latest products. His daily mobile tech life includes Android and iOS devices, smart rings, and a smartwatch, unless it's a special occasion, when a traditional watch takes its place on his wrist. Andy always has a strong opinion on the state of the mobile industry, and writes in-depth analysis features to put the latest news and products into context. He has attended multiple CES, MWC, and IFA tradeshows, has a passion for photography and cars, listens to far too much K-pop, and follows F1. You can find Andy's portfolio of work on his Authory page. The Samsung Galaxy Z Fold 8, Galaxy Z Fold 8 Ultra, and Galaxy Z Flip 8 have silicon-carbon batteries inside, bringing them right up to date, matching the competition, and finally answering demands from eager buyers. During a briefing at Galaxy Unpacked 2026, Samsung’s corporate EVP and deputy head of core component technology, BD Yang, explained why it’s a big deal for the company. A long time coming In-depth research Samsung Galaxy Z Fold 8 Ultra, Samsung Galaxy Z Fold 8, and Samsung Galaxy Z Flip 8 Samsung's adoption of silicon-carbon batteries goes beyond just a simple anode change, or popping in a new battery and calling it job done. The company spent a lot of time on research and development before launch. BD Yang explained: We have observed the demand for silicon-carbon batteries, and we are aware of others who already use them. Samsung holds itself to the highest standards in the industry when it comes to battery systems, and this new innovation isn’t only about changing the anode material. We embarked on system-level innovation that covers all the components that go into the battery end-to-end, and this allowed us to meet our standards. For the Galaxy Z Fold 8 Ultra, we increased the battery capacity to 5,000mAh, while maintaining a slim design. This required more than a large battery, it required redesigning the entire system. Samsung has introduced a silicon-carbon anode material. But improving battery performance required more than a new anode material alone. Silicon-carbon cells must be carefully managed because the performance and durability can vary depending on cell composition. To make them practical for everyday use, Samsung tuned the full cell system. This tuning involved optimizing the cathode and adding an electrolyte protective layer and separator, ensuring the cell remains stable. Through its engineering, Samsung has balanced the new silicon-carbon cells for usability, long-term battery life, and fast charging. The company would not comment on the percentage of silicon content in the new battery. New battery, faster charging What will it mean for performance? Yang continued, explaining how it has engineered its fastest Super Fast Charging 2.0 technology into the new Z Fold 8 models. Samsung has introduced 45W fast charging, and rather than sending the full charging power through a single path, the system divides and manages charging across separate paths, reducing electrical stress on each cell. It enables the Z Fold 8 Ultra to reach 67% charge in 30 minutes. The Z Flip 8 applies the same principle through a charging structure optimized for the compact design. While charging architecture differs between models, the goal remains the same. To ensure each battery system balances speed, safety and long-term reliability. By adopting silicon-carbon, Samsung can better compete with other folding phones released this year, including the Honor Magic V6, Oppo Find N6, and the Motorola Razr Fold. What isn’t clear is how much the increase in capacity for the Z Fold 8 Ultra and the adoption of silicon-carbon will affect daily battery life. We’ll know more when we review the new phones, but in our experience so far, silicon-carbon batteries, despite often having a large capacity, don’t stretch battery life that far beyond older battery technology. However, Samsung does appear to have put a lot of effort into optimizing its silicon-carbon batteries, and it’s certainly not the first brand to adopt them, meaning Samsung may have found a way to squeeze more from its new battery cells than the competition. Samsung Galaxy Z Fold 8 SoC Qualcomm Snapdragon 8 Elite Gen 5 for Galaxy Display type Dynamic AMOLED 2x 120Hz Display dimensions 7.6-inch open / 5.5-inch closed RAM 12GB / 16GB Storage 256GB / 512GB / 1TB Battery 4,800mAh The Samsung Galaxy Z Fold 8 has a 4:3 aspect ratio open screen, making it great for video and reading books, and when closed the device is compact, with apps on the cover screen appearing normally. It joins Samsung's Galaxy Z Fold 8 Ultra, which has a more traditional tall-and-thin design. Charge speed 45W Super Fast Charging 2.0 wired / wireless Operating System Android 17 / One UI 9 Front camera 10MP main / 10MP cover Rear camera 50MP main / 50MP wide Wi-Fi connectivity Wi-Fi 7 Dimensions 124 x 161 x 4.5mm open / 124 x 82 x 9.7mm closed Weight 201 grams Colors Lavender / Graphite / Cream / Pistachio (online exclusive) Material Armor Aluminum Samsung Galaxy Z Fold 8 Ultra SoC Qualcomm Snapdragon 8 Elite Gen 5 for Galaxy Display type Dynamic AMOLED 2x 120Hz Display dimensions 8-inches open / 6.5-inches closed RAM 12GB / 16GB Storage 256GB / 512GB / 1TB Battery 5,000mAh The Samsung Galaxy Z Fold 8 Ultra is a productivity-focused big-screen folding phone, with an emphasis on power and performance over the more media-focused Galaxy Z Fold 8. However, the specification is similar, with the camera and battery being the standout upgrades over the Z Fold 8. Charge speed 45W Super Fast Charging 2.0 / wireless Operating System Android 17 / One UI 9 Front camera 10MP main / 10MP cover Rear camera 200MP main / 50MP wide / 10MP 3x telephoto Wi-Fi connectivity Wi-Fi 7 Dimensions 158 x 143 x 4.1mm open / 158 x 73 x 8.9mm closed Weight 215 grams Colors Violet Shadow / Graphite / Cream / Green Shadow (online exclusive) Material Armor Aluminum Samsung Galaxy Z Flip 8 SoC Qualcomm Snapdragon 8 Elite Gen 5 for Galaxy Display type Dynamic AMOLED 2X 120Hz Display dimensions 6.9-inch open / 4.1-inch closed RAM 12GB Storage 256GB / 512GB Battery 4,300mAh The Samsung Galaxy Z Flip 8 takes the long-established compact folding phone formula and refines it further, reducing the weight and thickness to make the phone even more convenient to hold and carry. The rest of the specification is not a huge jump over previous models though. Charge speed Super Fast Charging / wireless Operating System Android 17 / One UI 9 Front camera 10MP Rear camera 50MP main / 12MP wide Wi-Fi connectivity Wi-Fi 7 Dimensions 167 x 75 x 6.1mm open / 86 x 75 x 13.1mm closed Weight 180 grams Colors Graphite / Pink / Cream / Mint (online exclusive) Material Armor Aluminum