Samsung has finally switched to a silicon-carbon battery in the Galaxy Z Fold 8. What’s so special about it?
Samsung has finally joined the silicon-carbon battery race with its latest batch of premium folders packing new battery technology. But the details of this change were hard to see in the spec sheets. The company confirmed during a press conference that the Galaxy Z Fold 8 Ultra, Galaxy Z Fold 8, and Galaxy Z Flip 8 all use silicon-carbon batteries.
However, the resulting abilities are by no means record-breaking. The Fold 8 Ultra packs a 5,000mAh battery, the regular Fold 8 gets 4,800mAh, and the Flip 8 has 4,300mAh. Competitors from Honor and Motorola have already surpassed the 6,000mAh mark. But statistics only tell half the story.
What is a silicon-carbon battery?
Silicon-carbon batteries are always a type of lithium-ion battery. The main change takes place inside the anode, one of the electrodes responsible for storing and releasing lithium ions during charging and discharging. Conventional lithium-ion batteries use mostly graphite in the anode. Silicon can hold much more lithium than graphite by weight, giving battery makers a path toward higher energy density.
High density creates two useful options for phone manufacturers. They can fit more battery capacity in the same space, or keep the standard capacity while making the battery smaller and lighter. Folders will benefit greatly from either method. Every millimeter gained from the battery can be used to improve thickness, weight, or color.
However, pure silicon poses its own engineering challenges. It expands as it absorbs lithium while charging, then contracts as the battery discharges. Repeated stretching can crack the material, damage internal connections, and accelerate battery degradation. That’s why silicon-carbon designs combine silicon and carbon-based material to better control that expansion.
How the Galaxy Z Fold 8 Ultra helped you
The best example of how this technology has helped Samsung is the Z Fold 8 Ultra. Its 5,000mAh battery is 600mAh larger than the 4,400mAh cell in the Galaxy Z Fold 7. That results in an increase of almost 14%. Samsung has made that leap while reducing the bezel size from 4.2mm to 4.1mm. Both generations weigh 215 grams. The company also claims up to 27 hours of video playback, compared to 24 hours on the Fold 7.
An additional 600mAh may sound modest next to the larger cells from Chinese manufacturers. The global Honor Magic V6 has a 6,660mAh silicon-carbon battery inside a body that measures 4mm when open. Meanwhile, Motorola’s Razr Fold uses a 6,000mAh silicon-carbon battery while measuring 4.6mm unfolded. It also supports 80W wireless charging and 50W wireless charging, which gives you a big advantage over Samsung on paper.
So when you compare it to other foldables out there, the Z Fold 8 Ultra looks the same. It would be easy to dismiss Samsung for this, but official briefings have given us a better understanding of the company’s priorities. Samsung emphasized performance, longevity, and safety. The company also said that users should expect battery life consistent with previous Galaxy products. Samsung appears to be limiting silicon content or using conservative cell design until it has more confidence in long-term performance.
Similar to Apple, Galaxy devices are looking to improve the experience and improve the user experience with new models rather than introducing big numbers. There’s an argument to be made on both sides of this, but considering past events, Samsung’s cautious approach isn’t surprising.
This is just the first step for Samsung
Samsung is a latecomer to silicon-carbon batteries. Some brands are already using technology to push phone batteries beyond what once seemed unrealistic. Galaxy’s first attempt may not hit the headlines, but the direction is clear.
Future Galaxy phones may use higher percentages of silicon and greater power. The technology could eventually make its way to standard Galaxy S devices, where it could power thicker batteries or smaller designs. Meanwhile, silicon-carbon has helped Samsung make its new foldable smaller without leaving battery capacity behind. Now we’re getting better-built foldables than ever before, and after years of 4,400mAh Galaxy Folds, I’m going to take a small but deliberate step.
