The Tecno Spark Slim has been released. iPhone 17 Air and Galaxy S25 Edge may lose the battle for the thinnest smartphone

2025 promises to be the year of ultra-thin smartphones. Samsung is preparing to release the Galaxy S25 Edge, Apple is working on the iPhone 17 Air, but suddenly there’s a new contender on the scene. Chinese company Tecno has unveiled the Spark Slim, the world’s thinnest smartphone with a 5,200 mAh battery.

The Spark Slim is the world’s thinnest smartphone with a 5,200 mAh battery.

Tecno Spark Slim: record thinness and a bigger battery

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Ahead of MWC 2025 Tecno announced Spark Slim – a concept smartphone that is only 5.75mm thick. Despite its incredible compactness, the device is equipped with a capacious battery 5200 mAh and a dual camera system of 50 MP each.

Spark Slim is a concept smartphone.

But for now, it’s just an concept. Tecno hasn’t announced a release date, and while demos can be seen at MWC 2025, there’s no guarantee that the Spark Slim will be available. A similar situation has already happened with Tecno’s ultra-thin foldable smartphone, which never made it to market.

Tecno’s Spark Slim is the first of its kind.

Spark Slim specs

The smartphone features 6.78-inch AMOLED screen with a resolution of 1224p and a refresh rate of 144Hz. Maximum brightness reaches 4500 nits, and there’s a 13MP front camera for selfies.

The battery is 4.04mm thick, and it supports 45W fast charging. The camera unit protrudes slightly above the body, but even with it, the smartphone remains incredibly compact.

At the same time, it’s still a very compact device.

How did Tecno manage to make such a thin smartphone?

The secret lies in new battery technology. Spark Slim uses silicon-carbon batteries, which have increased energy capacity while being smaller. A similar approach was used in the OnePlus 13, allowing for the placement of a 6,000 mAh 6,000 mAh battery without increasing the thickness of the case.

OnePlus 13 is a similar approach.

For comparison:

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• Galaxy S25 Edge will be about 6mm and get a 4000mAh battery.
• iPhone 17 Air is rumored to be thinner – around 5.5mm, but with a smaller battery capacity.

Tecno plans to reveal more details about the Spark Slim at MWC 2025, which starts as early as next week.

Conclusion

Although the iPhone 17 Air and Galaxy S25 Edge claim to be the thinnest smartphones of 2025, the Tecno Spark Slim may beat them to it. If it does go on sale, it will be a revolution in the world of ultra-thin devices with large batteries. For now, though, the big question remains whether it’ll go beyond the trade show booths.

The Tecno Spark Slim is out. iPhone 17 Air and Galaxy S25 Edge may lose the battle for the thinnest smartphone was first published on ITZine.ru.