The phone market has seen its fair share of groundbreaking and quirky innovations. While some inspired/forced the industry to adopt, others left a bad taste in the mouths of users and manufacturers, never to be seen again. However, some innovations intrigued us but failed to pick up pace due to then technological challenges. One of them being slim phones, a category that disappeared like a fleeting trend. Fast-forward a decade, and slim phones seem to be making a comeback. But why now? Let’s find out.
Why The Sudden Emergence of Slim Phones?
If you’ve been following the smartphone space, you might be aware of the upcoming Galaxy S25 Edge. For the unheard, with the S25 Edge (previously rumored to be the S25 Slim), marks Samsung’s re-entry into the slim phone market. The move seems to be inspired by Apple’s upcoming iPhone 17 Air, which is also rumored to be coming very soon.
The Korean giant’s motivation is probably to stay ahead of the game, which is fair. Although Samsung seems to be taking things a little too fast in that pursuit, settling for a smaller 4,000 mAh battery. While it should still last decently well, it’s far from the best and what Samsung could’ve offered. I’m referring to the possibility that Samsung could’ve thoroughly tested out Silicon-Carbon batteries.
Smartphone maker Tecno showcased the Spark Slim at MWC 2025 with a 5,200 mAh battery while coming in at just 5.75 mm. This is thanks to the Silicon-Carbon battery technology, where batteries use denser Silicon-Carbon anode that can hold more power than traditional Lithium-ion‘s graphite anode. The result? A 20-30% increase in overall capacity with the same or smaller dimensions than Lithium-ion.
The upcoming Slim phones — Galaxy S25 Edge and iPhone 17 Air are rumored to arrive at 5.84 mm and 5.5 mm thin, respectively. Considering Apple and Samsung are usually late to adopt latest technology trends, we can assume that neither of the brands will use Silicon-Carbon batteries. In a typical fashion of Android brands trying to mimic Apple, we should see more slim phones emerge in 2025.
A Look Back at Early Slim Phones
Those following the smartphone space from the early 2010s may know that Samsung’s no stranger to slim phones. The Galaxy A8 launched in 2015 was the firm’s slimmest modern smartphone, measuring just 5.9 mm.
Soon other manufacturers followed. Like Vivo X5 Max, which was the slimmest phone ever made at just 4.75 mm. Likewise, the OPPO R5 measured 4.85 mm, and Motorola’s Moto Z came at 5.2 mm. My 14-year-old self vividly remembers seeing X5 Max adverts all around the streets. And, my brain left in awe, questioning about just how slim these phones can get.
Some of these phones packed specifications like AMOLED displays, decent mid-range processors, and surprisingly, headphone jacks despite being so thin. Not only that, Vivo also managed to put a Yamaha DAC into the X5 Max.
The battery capacity was merely an afterthought in these devices, though. The 2,000 mAh batteries paired with extremely power-hungry 1080p displays and inefficient 28nm SoCs meant the phones barely lasted for 3 hours on a full charge.
Moto had a solution for the poor battery life with the custom Mods on the original Z and Z2 but besides the Mods receiving an underwhelming response, the Z series had their own issues to deal with, notably software optimizations and quality control. Perhaps it wouldn’t have ended badly for the Z series had Moto tried to fix these issues.
It was soon clear to firms that they simply lacked the tech to make it work. And despite their best efforts, slim phones were soon erased from existence. But could a decade of advancements in optics and batteries finally make slim phones successful? To answer that, we need to draw parallels with another form factor.
Are “Slim” Phones The New “Small” Phones?
It’s quite obvious that the reason manufacturers seem to be back at making slim phones is to give users devices that are easy to hold and carry. Now, if you think that sentiment sounds familiar, that’s exactly what pushed small phones forward. So, are slim phones the new small phones, then?
Although I would’ve cheered much louder had Silicon-Carbon batteries were used in small phones, slim phones could serve a few use cases. They should be easy to hold, pocket-friendly, and aesthetically cool-looking. All are valid points, but they could still feel incredibly niche, more so than small phones.
On the other hand, small phones address a major consumer want/need, i.e., one-handed usability, which made them a tad bit appealing, somewhat more useful than slim phones. Besides, small phones, due to their form factor, naturally excel in providing a better in-hand feel and pocket-friendliness. Therefore, between the slimmer form factor and larger screen, or better pocketability and one-handed use, most would choose the latter.
The Trade-offs: Thinness at What Cost?
If you still need a slim phone, you shouldn’t ignore existing slab smartphones, which have achieved significant breakthroughs in design and functionality. They’re already quite slim. Take the OnePlus 13 for example. Its predecessor, the OnePlus 12 rocked a 5400 mAh battery while being 9.2 mm thick without the camera bump. The OnePlus 13 (review), despite packing a 6000 mAh battery, manages to be just 8.5 mm thick. The iQOO 13 (review) too went from 8.35 mm to under 8 mm.
The bottom line is, shaving off a few millimeters in thickness often comes at the expense of smaller battery (still), inferior optics due to the lack of space, compromised structural integrity, and performance throttling. These trade-offs may not be worth it for most users.
While the slim vs small phone topic is worth debating further, it’s important to remember that both form factors are nothing but niche. However, unlike small phones, slim phones don’t solve any major problems except for looking great.
While the improvements in battery technology, efficient processors, displays, and various components might delay their demise, it’s a form factor that comes with sacrifices, and may not survive as a result. Slim phones are essentially taking on the small phone market, but small phones are just more practical.
Who Are Slim Phones For? Will They Survive the Next Wave?
The target audience of slim phones are clearly business professionals, executives, influencers, trendsetters, and aesthetic-first users who appreciate minimalism. It’s clear that slim phones, while now better than decade-old attempts, are still mostly for the looks.
And I think that’s where brands need to reinvent this category to please both slim and small phone aficionados. That’s something OnePlus is looking to do with its upcoming small phone, the OnePlus 13T. While the exact specifications are unknown, a rumored 6.32 inches screen, 7.8 mm thickness, and a 5,800 mAh battery, the phone might just be the perfect middle-ground. Besides, the Xiaomi 15 is another “small” yet pretty slim device at 6.3-inches and 8.1 mm that you can buy.
The true small phone category died with the iPhone SE 3 and although not exactly small, phones like the Galaxy S25 (review), Pixel 9 (review), Xiaomi 15 (impressions), carry the legacy. They boast smaller displays with thinner bezels, adding to better reachability and pocketability. A few of them sport a Silicon-Carbon battery, and combined with their already “slim” form-factor, they make slim phones seem redundant.
While the Galaxy S25 Edge could still beat them in sheer slimness, but the difference will thin further (pun intended) when more manufacturers introduce the new battery tech. This could eventually make the trade-offs seem more negligible, ultimately leading to the second demise of slim phones.
What are your thoughts on Slim phones? Do you think they’re better than small phones? Let us know in the comments below.
Source: Beebom