Xiaomi's battery and fast charging technology has been around for a decade

One of the few remaining areas in the smartphone world where proprietary technologies can thrive is battery charging. The majority of companies buy chipsets from the same suppliers, as well as screens and camera sensors. However, batteries and accompanying hardware are sometimes completely customised, and this has been a field of rapid innovation in recent years.

Okay, USB Power Delivery is a viable option; in fact, some may argue that it is the best option due to its widespread support. On the wireless charging front, the same argument can be made for Qi. However, proprietary systems currently allow for faster speeds and are used on some notable devices.

This week, we'll look at how battery and charging technology has progressed over the last decade, with a focus on Xiaomi. For the most part, we'll be looking at averages, but we've also included maximum values because they tell a compelling story.

"Give me a big battery, even if the phone is thick," people frequently say. To their credit, neither Xiaomi nor other smartphone manufacturers appear to share that sentiment. As you can see, Xiaomi phones' average thickness dropped steadily for a while before stabilising around 9mm. However, thanks to technological advancements, the average battery capacity has increased over time.

With ever larger batteries, charging at the USB baseline of 10W would take an increasing amount of time, so something had to give. Xiaomi's first fast-charging phone was the Mi 3 (2013), which used Qualcomm's Quick Charge 2.0 to charge at 18W. In fact, QC was used by Xiaomi in a number of its devices. The Mi 9 Pro (2019), for example, had QC 4+ and could charge at 40W wired and 30W wireless.

However, Quick Charge was unable to keep up, and Xiaomi's phones with the highest charge ratings switched to a proprietary solution. As we mentioned in the introduction, it's one of the areas where in-house technology, such as the Surge P1 charging chip, can help companies stand out.

The capacity of batteries did not continue to increase indefinitely. Xiaomi had a Mi Max series a few years ago, with large displays and large batteries. The second model had a 5.300mAh battery and a 6.44" display. The third one had a 6.9" display and a 5,500mAh battery. Those, however, were not the company's largest batteries. Instead, phones like the Poco M3, which is affordable and not too big, have 6,000mAh batteries (the M3 measures 162.3x77.3x9.6mm and weighs 198g). Xiaomi has never gone higher than 6,000mAh in terms of battery capacity.

While digging through the data, we discovered a few interesting things. Xiaomi's Mi Mix 2S was the first phone to support wireless charging, with a 7.5W output. With the phone, the company also released the first official Qi charger.

Despite this, the company appears to have shifted its focus to wired charging. Phones like the Xiaomi 11i HyperCharge 5G exist solely to provide users with the option of super fast 120W charging – in our test, a full 0-100 percent charge took 16 minutes. To save battery life, disable Boost mode for 22 minutes. In the meantime, only a few models released in the last few years support wireless charging at 50W or higher.

How quickly can charging technology advance? There is a lot of headroom when it comes to the USB-C cable. The most recent USB Power Delivery specification allows for a whopping 240W of power. A year ago, Xiaomi was demonstrating a 200W charger. It also comes with an 80W wireless charger.