How Samsung slimmed down Galaxy Z8

LONDON — Samsung Electronics has rebuilt its Galaxy Z8 foldables around titanium and silicon-carbon, betting that a new display structure and battery can make them thinner, tougher and longer-lasting.

The overhaul goes beyond individual components, with Samsung redesigning the display, hinge, battery and thermal management system as an integrated platform rather than upgrading each part separately.

“You cannot create meaningful innovation by improving just one component,” Moon Sung-hoon, head of the mobile hardware research and development office at Samsung Electronics’ Mobile eXperience division, said during a media briefing in London on Thursday. “Every major part has to work together as one system.”

At the center of the redesign is Flex Titanium, Samsung’s new display support structure developed to reduce device thickness and improve the folding experience.

The structure combines a titanium support plate beneath the display module with a newly developed titanium alloy film placed directly under the OLED panel. The film replaces the polymer support layer used in previous generations and helps reinforce the crease area, reducing deformation caused by repeated folding.

Samsung also redesigned the titanium plate’s internal lattice structure using chemical etching and laser processing, allowing the folding area to move more flexibly while maintaining rigidity.

“The titanium alloy film supports the crease area from underneath, minimizing sagging and improving the overall folding experience,” Moon said.

Samsung said the redesigned display module is about 10 percent thinner than the previous structure. The space gained from the slimmer architecture was used for other components, including a larger battery, improved thermal management and upgraded camera hardware.

The Galaxy Z8 Ultra is Samsung’s thinnest foldable smartphone to date, measuring 4.1 millimeters when unfolded while housing a 5,000-milliampere-hour battery, according to the company.

Moon said achieving the thinner form factor required engineers to rethink the entire device architecture rather than optimize individual parts.

Samsung’s other major hardware change is the introduction of a silicon-carbon composite battery, which is being used in a Galaxy smartphone for the first time.

Silicon-carbon technology enables higher energy density than conventional graphite-based batteries because silicon can store more lithium ions within the same volume. The technology is particularly valuable for foldable devices, where manufacturers must increase battery capacity without adding bulk.

However, silicon expands and contracts more significantly during charging cycles, creating challenges for long-term stability.

Samsung said it addressed the issue by redesigning the battery cell as a whole. Engineers applied a carbon coating to stabilize the silicon anode while also improving the cathode, electrolyte and separator to maintain performance and durability.

“Developing a silicon-carbon anode alone wasn’t enough,” Moon said. “We optimized every material inside the battery cell and validated its performance under high and low temperatures as well as long-term usage before commercialization.”

Samsung said the new battery technology increased capacity across the Galaxy Z series by about 15 percent while maintaining a thinner and lighter design.

The Galaxy Z8 series also introduces 45-watt wired fast charging to Samsung’s foldable lineup. The company said the charging system independently controls two battery paths to improve charging speed while managing heat generation.

Samsung said the Galaxy Z8 Ultra can recharge to 67 percent in about 30 minutes.

Moon said Samsung is not pursuing battery capacity alone, noting that simply increasing battery size could undermine the advantages of foldable devices if it leads to heavier and thicker products.

“A larger battery doesn’t necessarily translate into a better user experience if the device also becomes heavier and thicker,” he said. “Our goal is to increase battery capacity while preserving the slim, durable and lightweight characteristics customers expect.”

Samsung said future battery development will focus on balancing energy density, power efficiency, weight and overall usability, while silicon-carbon batteries could gradually be added to other Galaxy smartphones if they improve the overall user experience.

“If we believe a technology delivers a better overall customer experience after considering every aspect of the product design, we’ll actively expand its adoption,” Moon said.