Silicon Carbon Batteries Explained: Why Big Brands Are Still Waiting

There are many Smartphone out now with absolutely massive batteries , the size that we only used to see in power banks,

but without actually making the phones any thicker, all thanks to a new battery technology called silicon carbon Batteries .

What Is Silicon Carbon Battery Technology?

So, if you’re a subscriber, then you’ve already heard me talk a lot, especially in the past year, about silicon carbon batteries and how great they are and how they’re even perfect for certain form factors of phones, like enabling the ultra-thin ones like Galaxy S25 Edge and iPhone Air, because they could be super, super thin, but still with silicon carbon have normal battery capacities. But yet, those phones didn’t have silicon carbon.

In fact, a lot of phones, competitive flagship phones, have come out lately that have skipped the silicon carbon battery. It seems like whole companies like Samsung and Apple and Google are just waiting on the sidelines and not touching this new battery tech in any of their phones. And I finally think I know why.

Why Silicon Carbon Looks Like a No-Brainer

So, let’s talk about these new smartphone batteries. So, like I said, on the surface, it would seem like silicon carbon is a no-brainer. Obviously, you should have it in your phone, especially if you’re just looking at the benefits. They’re called silicon carbon because they essentially swap out graphite and use silicon, which can hold way more energy than graphite.

So, the main advantage is higher energy density. We have phones now with way bigger battery capacities in the same footprint as always. I remember when the new OnePlus flagship came out last January, and it made this huge jump from 5,400 mAh straight to 6,000 mAh by going with silicon carbon. And then later the same year, they went to 7,300 milliamp hours. So it just felt like we are resetting what to expect from a smartphone battery.

Why Apple, Samsung, and Google Are Holding Back

But of course, like I mentioned, new Samsung phones keep coming out, no silicon carbon batteries. New iPhones have been coming out, no silicon carbon. Even new Pixel phones, same thing. And so people, of course, are talking about it.

Now, I’d had some suspicions about why, and a couple of other YouTubers have also shared, but I think the main theory was that these are huge companies that are going to ask for massive quantities of stuff from suppliers. So, with a brand-new tech like silicon carbon, you know, if you’re Apple, you’re going and asking for 10 million of these things for your new iPhone. And maybe that wasn’t possible yet.

But then again, Xiaomi is huge and they’re using silicon carbon in all their flagships, and Realme and Honor and Oppo and Huawei, and all these companies’ using tons of silicon carbon in a lot of volume of phones. Meanwhile, Google’s over here with the Pixel not shipping that many phones and not using silicon carbon. So maybe that’s not the whole story.

The Real Concern: Swelling and Longevity

So then I recalled I’ve I’ve gotten a few emails in the past year from people in the industry, and I won’t say which companies they work for, but all smartphone companies, and individually they’d each reached out to me to mention that there are some concerns with silicon carbon batteries, and all their stories matched up about a totally different concern about swelling and longevity.

Now, I had only seen that in these emails. So, I went digging and I reached out to a couple of other sources and people that I know at these companies. And now that I’ve heard back from them, I’m actually much more confident that this is the main reason that we’re not seeing this tech everywhere in a ton of phones.

How Battery Expansion Becomes a Risk

See, one thing about batteries is that as they charge and discharge, they expand and contract a little bit with the heat, just like almost any other material. It’s why sidewalks have cracks. It’s why bridges have expansion joints. Basically, every material has to expand and contract a little bit with heat, right?

Fun fact, water is one of the only materials that actually expands while cooling, but it expands about 10% in volume while freezing. And if that happens too fast, it cracks.

So during charging in a silicon carbon smartphone battery, the silicon heats up and absorbs lithium ions. And when that happens, the silicon can expand to three times its original volume. So that’s kind of insane.

Like imagine a sponge that triples in size when wet and then shrinks back down, and then over and over again every time it charges and discharges. Eventually, things are probably going to crack.

You know that meme going around where it’s like, “Oh, if you want to clean the ice off your car windshield really fast, just pour boiling water on it.” But obviously, you shouldn’t do that because that could literally shatter your windshield because of rapid temperature change thermodynamics.

Engineering Challenges and Safety Concerns

So in the battery, the silicon is actually really finely ground instead of a solid block to avoid the mechanical stresses, and the carbon is actually there just to absorb the expansion. So that’s why it’s called silicon carbon.

So everyone’s messing around and trying to tune it. Some companies are willing to include a higher and higher percentage of silicon because that lets you get a higher and higher battery capacity in the same space, but that’s also pushing the limits.

And so they also have to do their best to manage the inevitable swelling to counteract that. It’s just physics or chemistry.

I’ve I’ve actually been told there are certain devices that have a literal steel cage around the battery to prevent it from swelling. And then the cracking in this case is potentially some type of internal damage to the battery, which is obviously really bad news. And worst-case scenario is some type of thermal runaway, which obviously nobody wants that happening in their pocket.

Why Testing Isn’t Enough at Massive Scale

And so you might be thinking, oh, what about all the testing? Like, that’s one of the most common things we hear from these companies is they’re always able to verify something like, you know, 80% battery capacity after a thousand charge cycles.

But batteries obviously go through a lot more in regular use than just charge cycles. Like they deal with a lot of outside heat and cold. They get dropped sometimes. There’s pressure changes, there’s humidity changes, etc., etc. It’s a long list.

So, testing is really important, of course, but it’s really hard to account for all the variables that a battery might experience over a long period of time.

In one of my conversations, my source mentions that with all the thorough testing going on, getting issues down to a rate of under one in 250,000 feels pretty good. But at Samsung or Apple’s scale, if it’s tens of millions of phones, that could still not be good enough.

That could still be a dozen exploding Note 7s, like it was in 2016.

Market Differences and Risk Tolerance

And you know, remember those companies I mentioned at the beginning that are all not using silicon carbon?

The US, especially, is a very software-focused market. There’s all this ecosystem lock-in and inherently less hardware competition. People just want the blue bubbles at this point.

So, if people aren’t going to buy the new iPhone because of a silicon carbon battery, or they’re not switching off of the iPhone because of some other phone’s silicon carbon battery, then there is no reason for Apple to take that risk yet.

But in other markets where people can just use WhatsApp and be happy about it, then there’s way more hardware competition and people are willing to switch.

Final Thoughts

This will be fascinating to watch it play out. Today still in 2026, silicon carbon batteries are still a bleeding-edge technology. They’re still a little bit riskier, and lithium-ion batteries are still the safe bet.

But there’s this divide now. So, we’ll have to keep an eye on how these silicon carbon phones actually age. The first ones came out about three years ago, but there’s been a lot more out in the real world in the past year.

CREDIT GOSE TO :

Editor in chief : Ghulam mujtaba

Resource: Marques Brownlee