Electric car battery tech will supercharge your next smartphone

The first time I used the Honor Magic V3 last year, I couldn't believe my eyes. The phone was so stupid thin I was sure it wouldn't last a day on a single charge, much less be able to sustain top-end performance while playing games. To my astonishment, it passed both of those tests with flying colors, and this year's Magic V5 is even thinner.

If you can believe it, despite being even thinner than the previous year's phone, the Magic V5's battery is 13% larger. It seemingly makes no sense, especially given that the battery is 32% larger than the similarly thin Samsung Galaxy Z Fold 7. While it might sound like voodoo magic, the secret comes from a place you might not have expected: electric cars.

Honor has been using these silicon-carbon batteries for a few years now, and each year they improve. This year, we got an even bigger bump than usual, and it's enabling phones to get thinner without compromising on important things like battery life and charging speed.

From cars to smartphones

Group14 Technologies is the company behind the big push for more silicon in our batteries, and a lot of this push began with the need for more energy in electric cars. Cars, after all, require a lot more power to function than your average smartphone, so it was important to figure out how to get a larger capacity battery that also charges quickly into the same size form factor.

This is done by taking the traditional lithium battery material, graphite, and blending it with silicon in the anode part of the battery. Electric car anodes can have up to 30% silicon blended with graphite, while the Honor Magic V5 tops out at 15%, which is still the most we've seen in any smartphone to date.

Since silicon stores a lot more energy in the same space as graphite, manufacturers can create higher-capacity batteries that fit in the same space. In an ultra-thin phone like the Honor Magic V5, Galaxy Z Fold 7, Galaxy S25 Edge, or even the iPhone Air, a larger silicon-carbon battery can make your thin phone feel like magic. It's just too bad Samsung, Google, and Apple aren't using them at all.

The charging test

Earlier this summer, we learned about how regulations could be keeping battery sizes down. The gist is that shipping regulations cap a battery at 20Wh in capacity, which equates to roughly 5400mAh in the smartphone world. This restriction is partly why Chinese models typically have larger batteries than the global model of the same phone.

The Honor Magic V5 packs a 5,820mAh battery, while the Galaxy Z Fold 7 uses just a 4,400mAh battery. While this might sound like a problem for Honor initially, the trick is that this regulation is per cell, meaning companies have to use dual-cell batteries. The good news is that companies like OnePlus and Honor have been doing this for years.

Using a dual-cell battery also ensures faster charging rates since you can charge two cells in tandem. Samsung, Google, and Apple don't do this, and it's one of the reasons they charge so slowly.

Phones with dual-cell batteries in the table above — that's the OnePlus 13 and Honor Magic V5 — charge substantially faster despite having larger batteries. Swapping out graphite for silicon also reduces weight, making this a win-win situation for design.

Longevity and cost

It's always peculiar when three of the world's largest smartphone manufacturers don't follow a trend. In more than one way, it reminds me of how every company but Samsung, Google, and Apple have made their phones more friendly for PWM-sensitive people (until the iPhone 17 came along, that is).

Some people cite cost as a main reason not to use silicon-carbon batteries, but that doesn't seem to make much sense given the cost of the premium phones from these brands. Packing in a dual-cell battery costs a little bit more money per phone, but it would make sense to use these batteries on ultrathin phones like the iPhone Air, Galaxy S25 Edge, and Galaxy Z Fold 7.

In Samsung's case, the Galaxy Note 7 is still haunting the company, making it hyper sensitive about any major changes in battery or charging tech. The company told T3 that they're developing a silicon-carbon battery that's "reliable," as if current SC battery tech somehow isn't.

The Verge wrote about how silicon degrades faster than graphite, a legitimate concern considering companies like Google are actively throttling phone batteries as soon as 200 charging cycles. But Group14 says its silicon-carbon batteries will exceed the lifetime charging cycles of existing products by a significant amount.

We'll need a bit more time to see if that turns out to be true, as the first major phone with a silicon-carbon battery was 2023's Honor Magic 5 Pro. But even if you bought that phone on day one and charged it every single day since then, you still wouldn't have hit 1,000 charging cycles, which is when Google caps the Pixel 10's battery at 80% capacity.

Using the Honor Magic V5 again as the final example, it's battery is made up of 15% silicon-carbon, making the battery 32% larger than the Galaxy Z Fold 7's. Even at an 80% capacity reduction after 2.5 years, it would still have a larger capacity than a brand-new (and, therefore, unused) Galaxy Z Fold 7.

That's enough of an argument alone to me and a reason why silicon-carbon isn't just the future of smartphone tech; it's the reason you should choose brands not named Samsung or Google.