Why more and more mobile phones last up to two days and weigh less

Technological devices have been chained to the chemical limitations of lithium-ion batteries for almost 30 years. Until recently, if we wanted a mobile phone to have more autonomy, what we needed was a much larger battery. This, in the end, translated into much thicker and heavier phones.

That has changed in recent years, since in the middle of 2026 we are witnessing a change in the x-ray of batteries. Now, there are mobile phones on the market that they do not exceed 7 mm thick (as is the case with the Honor Magic V3, which when deployed has a thickness of just 4.35 mm) and which are capable of mounting 5,500 or 6,000 mAh batteries (or even more) without the design looking crude. The secret is not magic, but the anode silicon-carbon.

How to understand this progress?

In order to understand this progress, we must look inside the battery. Traditional ones use graphite in the anode – the negative electrode –, a cheap and stable material, but with a clear capacity limit. This means that a lot of graphite is needed to be able to store an amount of energy for our mobile phone.

He silicon It is a “supermaterial” that can store up to 10 times more lithium ions per gram than graphite (with a specific capacity of around 4,200 mAh/g compared to approximately 370 mAh/g for graphite). This translates into smaller batteries for the same autonomy or more autonomy in the same space.

If silicon has such advantageous properties, why isn’t it used sooner? The answer is given by its defect and that is that it is a material that can reach expand by 300-400%depending on the type of silicon used. This is something that could end up fracturing the battery of our mobile phone with just a few charging cycles.

This has currently been solved in mobile phone batteries, managing to encapsulate silicon nanoparticles within a carbon structure, which functions as a cage. He carbon It acts as a shock absorber, allowing the silicon to expand and contract internally without destroying the physical structure of the battery.

Benefits of mobile phones that have this type of battery

The fact that this technology is being implemented in mobile phone batteries basically offers us three benefits that can be translated into the following:

• Higher energy density: It is now possible to mount a 5,800 mAh battery in the space where a 4,500 mAh battery previously fit.
• Less thickness on mobile phones: Manufacturers no longer have to sacrifice design so that the mobile battery lasts until we go to sleep. This means that the thickness of today’s mobile phones (in the vast majority of cases) is decreasing.
• Better fast charging: This type of battery better supports high current densities. This allows us to do ultra-fast charging with less long-term battery degradation.

Some mobile phones that have this type of battery

A few years ago, Honor (it was one of the first brands to bring this technology to a high-profile folding device with the Honor Magic V3) and Xiaomi began to experiment with this type of batteries, although it is now that silicon-carbon has gone from being a luxury for become the new industry standard. These are some of the mobile phones with silicon-carbon batteries that you can buy currently.

• Xiaomi 17 (855.34 euros currently on Amazon): the latest release from the Chinese manufacturer, the Xiaomi 17 mount a battery 6,330 mAh on a phone with a thickness of 8.06 mm. This battery supports 100 W fast charging and 50 W wireless charging. Its photographic system signed by Leica is another of its assets, as is its 6.3-inch OLED screen.

• Samsung Galaxy S26 Ultra (1,559 euros on the Samsung website): after years with graphite, Samsung has implemented a hybrid silicon architecture in its S26 series. Of course, the 5,000 mAh remains, but the mobile is much thinner and lighter than the S24 Ultra (7.9 mm and 214 grams of weight S26 Ultra compared to the 8.6 mm and 232 g weight of the S24 Ultra). This Korean firm’s mobile is a clear example that the industry uses silicon-carbon not only to provide more battery, but to make phones more ergonomic without losing capacity.

• Honor Magic8 Pro (899 euros): As we have already said, Honor was the first brand to launch a mobile phone with this type of battery. He Honor Magic8 Pro It is its latest addition to the market. Your battery 6,270 mAh Not only is it thinner, but it also stands out for using a dedicated chip (E2; whose main function is to optimize consumption and stabilize the voltage at the minivolt level) to manage the silicon-carbon. Its autonomy is enough for a day and then some, something unthinkable recently on such a bright and fluid 120 Hz screen.

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Images | Xiaomi, Samsung, Honor and Álex Alcolea (Xataka Móvil and Xataka)

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