Since 2007, iPhones and Android phones have completely changed the mobile phone industry and how we interact with our devices and the world. For all the debatable good and bad this has brought, one thing the advent of the smartphone did directly affect was our phones’ battery life.

My first phone was the famous Nokia 3310, a poster child for the “brick” phone generation that sold more than 100 million units. The battery lasted for about a week if you didn’t use it much, which as an 11-year-old I didn’t. I was playing Snake 2 more than I was texting and calling.

Phone chargers were items we left at home for the weekend and power banks didn’t exist, because we didn’t need them. But we’ve surely all had our modern smartphones die on us on a night out, locking us out of calls, messages, banking, maps and cameras.

But the days of our smartphones only lasting a day on a single charge look like they are coming to an end, thanks to an emerging advancement in battery technology.

Most phones use traditional lithium-ion cells to stay powered up, but new Android phones have been released with silicon-carbon batteries instead, demonstrating immediate gains in longevity.

I tested the OnePlus 15, which lasted for three whole working days on a single charge, while other phones with silicon-carbon cells including the Vivo X300 Pro, Xiaomi 15 Ultra, Oppo Find X9 Pro and Honor Magic 8 Pro have all lasted at least two days for me.

So, why is this technology only just being used, and will it become a smartphone norm?

Silicon-carbon batteries have only been recently developed for use in consumer technology. The anode of these batteries, the part that delivers electrical current to the device, is a composite of graphite and silicon, rather than just graphite you’ll find on lithium-ion batteries.

Silicon can accommodate more lithium ions compared to graphite, the direct result of which is more efficient power drain and the ability to pack denser batteries into the same thickness of devices that we are used to, so you get larger capacities fit into devices of familiar size.

It means the 8.1mm thick OnePlus 15 has a 7,300mAh battery, compared to the 8.2mm Samsung Galaxy S25 Ultra, whose battery is only 5,000mAh.

Samsung is seemingly hesitant to adopt silicon-carbon batteries. Perhaps the global PR disaster of the Galaxy Note 7 still looms large, Samsung’s 2016 smartphone that was recalled two months after launch because of multiple reports of battery explosions. Samsung had packed a large cell for the time into the chassis, and the physics did not work out.

Today, Samsung phones’ battery sizes and battery life pale in comparison to those of Chinese smartphone rivals, who are pushing ahead with silicon-carbon in order to present a clear advantage to consumers who might switch phone brand to get better battery life.

I’ll admit that using a phone I genuinely did not have to charge for three days was mind blowing, but there are still things we don’t know about silicon-carbon.

Many of these Chinese-made phones also boast incredibly fast wired charging. The OnePlus 15 is capable of 120W charging, which can charge the device from 1-100 percent in 39 minutes. The Galaxy S25 tops out at 45W speeds, and is much slower to top up.

Fast charging tech is thought to degrade battery capacity faster, but much of the observation of this is still anecdotal, and phones with lithium-ion batteries also degrade over time. All batteries lose capacity as they are used – it’s just physics.

Whether or not silicon-carbon batteries will, via a combination of their physical make up and use of fast charging, degrade to an unacceptable extent remains to be seen. But Samsung and Apple, as the two bestselling phone companies in the world, are notably holding back on the technology.

Apple might have made a bigger splash with its thin, 5.6mm thick, £999 iPhone Air last year if the battery life had been better. But a smaller phone equalled a smaller lithium-ion battery, and many reviews complained that the phone couldn’t even last till dinner time. The same was true of Samsung’s £1,099 Galaxy S25 Edge, which charged a premium and had bad battery life.

The OnePlus 15 costs less than these phones at £849, proving you can buy a phone with a three day silicon-carbon battery in 2026 and not spend more than the competition for the privilege. If all smartphone manufacturers can bring this evidently better battery tech to phones of all prices, it will help give the slightly stagnant smartphone industry a shot in the arm.