Future Redmi phone may come with a massive 8500 to 9000 mAh battery

Xiaomi/Redmi is reportedly testing a new smartphone with a massive 8,500 to 9,000 mAh battery, Digital Chat Station claims. That would make its internal battery almost as large as most power banks from a few years back. If launched, this would likely be the first "normal" smartphone to come with a battery this large. The company recently launched the Turbo 4 Pro which comes with a massive 7,550 mAh capacity but there are even larger battery capacities to be found in "normal" consumer-grade phones, like those powering the Honor Power and iQOO Z10 Turbo Plus. In the meantime, larger rugged phones can have as much as 28,000 mAh.

The serial leakster also revealed that the upcoming Redmi phone's battery is being developed using in-house technology. The aim is to achieve the largest possible capacity without compromising on the amount of charge/discharge cycles.

Larger capacity batteries are now becoming the new norm thanks to silicon-carbon battery technology. As various sources note, lithium-ion batteries have energy density in the range of 250-300 Wh/kg whereas silicon carbon batteries can reach an impressive 400-500 Wh/kg.

The higher energy density for silicon-carbon batteries can be attributed to their greater lithium storage capability. They are also considered safer, as the design prevents the build-up of lithium deposits, a common cause of short-circuits. This technology has already made smartphones with batteries as large as 8,000 mAh possible and attempts are underway to enhance capacity even more.

In addition to cranking the new phone's battery capacity all the way up to the maximum, Redmi is apparently trying to ensure it does not end up being overly thick. As the tipster mentions, Xiaomi/Redmi engineers will do their best to keep the phone's thickness limited to 8.5 mm. For comparison, the Redmi Turbo 4 Pro measures 7.98 mm in profile while the Galaxy S25 Ultra is 8.2 mm thick despite housing a much, much smaller 5,000 mAh battery.