That said, I also dug into the reasons why mainstream brands still use reliable lithium-ion battery technology, and they're convincing.
So, while you could buy a OnePlus 15 in the U.S. today with a silicon-carbon battery, most people won't.
This behavior explains why many people have never encountered silicon-carbon battery tech, despite its popularity abroad.
It's too early to tell, but I'm rooting for silicon-carbon batteriesWe're still firmly in the "wait-and-see" phase of the silicon-carbon battery rollout.
The Motorola Razr Fold is a joy to use, in large part due to its 6,000mAh silicon-carbon battery.
Smartphone buyers in North America are used to watching from the sidelines as emerging technologies hit new models in Europe and Asia. There's no better example of this trend than the rise of silicon-carbon batteries, as they're still quite rare in the U.S. Apple certainly hasn't equipped an iPhone with the tech. Samsung, which has a heavy presence in the U.S., has shied away from transitioning to silicon-carbon batteries as well.
Silicon-carbon batteries are beloved for their ability to provide higher-capacity cells in a dense package, making for longer smartphone runtimes. I tried a phone with this technology that you can easily buy from a stateside carrier store — the Motorola Razr Fold — and it left me thrilled. That said, I also dug into the reasons why mainstream brands still use reliable lithium-ion battery technology, and they're convincing.
I loved using the Razr Fold's battery
It was a huge upgrade over Galaxy and Pixel foldables
While I prefer to purchase unlocked phones, the numbers don't lie — most buyers in the U.S. buy smartphones from their cellular carrier. It's not hard to see why, since carriers bundle phones with discounts and promotions that make their rising prices easier to stomach. There are always strings attached, but alas, this is how American buyers prefer to upgrade their phones.
This is a problem for any brand without a presence in AT&T, Verizon, or T-Mobile carrier stores, as a huge chunk of buyers will never see it. So, while you could buy a OnePlus 15 in the U.S. today with a silicon-carbon battery, most people won't. Instead, they'll buy the phones from Apple, Samsung, or Google that they can purchase from their cellular carrier.
This behavior explains why many people have never encountered silicon-carbon battery tech, despite its popularity abroad. Motorola is shaking things up with the Razr Fold, as it packs a 6,000mAh silicon-carbon battery into a foldable that you can pick up from a cellular carrier. Unlike the Razr Ultra 2026, which has a silicon-carbon battery as well but isn't available from major telecom companies, the Razr Fold is available where smartphone buyers shop most.
Credit: Brady Snyder / MakeUseOf
I've spent over a month with the Motorola Razr Fold in my pocket, and let me tell you, the device's battery life is incredible. I buy a couple of phones each year for personal use and test many more for work. There's always a new shiny gadget I'm waiting to try, but the Razr Fold is so good I don't want to give it up. That is the highest complement a reviewer can give, and I'm giving it to Motorola's first big-screen foldable.
I've used many foldables over the years, most recently the Samsung Galaxy Z Fold 7 and the Google Pixel 9 Pro Fold. I never felt comfortable with the battery life on either device. They each lasted all day when the cover screen was primarily used, but switch to the main display for a few hours, and it's a completely different story. The Razr Fold lasts a full day, and can even stretch into a second day of use.
The silicon-carbon battery is to thank, so why aren't more companies using the technology? My positive experience with the Razr Fold only made me more curious, and it turns out there are reasons Apple and Samsung are wary.
Related I didn't expect Motorola to build the best folding phone in the US Motorola took a Goldilocks approach to its Galaxy Z Fold 7 competitor, and the result is the best folding phone in the US right now.
There are downsides to silicon-carbon batteries
Faster degradation, more swelling, and overall reliability are key concerns
Credit: Brady Snyder / MakeUseOf
When batteries are working safely and properly, they're not something many of us think about. Batteries traditionally use a lithium-ion chemistry to store energy. This kind of battery uses a graphite anode to hold the lithium ions as it is charged and discharged. The material is stable, allowing lithium-ion batteries to safely charge and discharge for hundreds or thousands of cycles. While we remember the worst of battery failures, lithium-ion batteries have a failure rate that is quite low.
This battery chemistry and architecture comes with inherent density limits. What this means is that to increase the capacity of a lithium-ion battery, you have to make it bigger. For size-constrained devices like smartphones, that is difficult. This predicament explains why manufacturers are turning towards a new battery chemistry to increase capacity without increasing the size of the cell.
Silicon-carbon batteries use silicon to store a greater amount of energy, but it comes at a cost. While graphite anodes are relatively stable, silicon anodes are more susceptible to battery swelling. They can grow by up to 300% or more, and this is why pure silicon anodes aren't used in smartphone batteries. Carbon is added to stabilize the silicon, resulting in a stronger battery structure that might only swell by 10% to 20%.
Silicon-carbon batteries are about 10% to 20% denser than lithium-ion batteries, but this all depends on how much silicon is actually inside the battery cell. The drawbacks of using a pure silicon anode are mostly avoided when using a silicon-carbon chemistry instead, but they aren't completely thwarted. You still have to worry about swelling, and the extra battery stress that comes with it. This is why silicon-carbon batteries degrade at a faster rate than lithium-ion batteries.
In simple terms, a lithium-ion battery will last longer than a silicon-carbon one, on average. While the Razr Fold beats my Galaxy Z Fold 7 today, will the same be true in five or 10 years? That remains to be seen — and the uncertainty explains why Apple and Samsung aren't buying in yet.
Do the perks of silicon-carbon tech outweigh the risks?
It's too early to tell, but I'm rooting for silicon-carbon batteries
We're still firmly in the "wait-and-see" phase of the silicon-carbon battery rollout. There are plenty of phones on the market with silicon-carbon batteries inside, and I've tried a few of them. However, they haven't been around long enough to know exactly how they hold up over time compared to lithium-ion batteries.
After trying phones with silicon-carbon batteries and diving into the drawbacks that make mainstream brands avoid them, I see both sides of the argument. The Motorola Razr Fold is a joy to use, in large part due to its 6,000mAh silicon-carbon battery. However, if it degrades at a faster rate than phones with lithium-ion batteries, is it worth it? That's for you to decide.
