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Samsung Testing 12,000mAh, 18,000mAh Batteries With Dual Cell and Triple Cell Designs, Leaked Reports Show

Samsung Testing 12,000mAh, 18,000mAh Batteries With Dual Cell and Triple Cell Designs, Leaked Reports Show

A 20,000mAh prototype reportedly failed Samsung's tests after about 960 charge cycles.

Written by Sucharita Ganguly, Edited by David Delima | Updated: 10 March 2026 19:45 IST

Samsung Testing 12,000mAh, 18,000mAh Batteries With Dual Cell and Triple Cell Designs, Leaked Reports Show

Samsung Galaxy S26 Ultra (pictured) packs a 5,000mAh battery

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Highlights

Samsung SDI is refining battery stacking and management systems
Silicon-carbon batteries can offer higher capacity in similar sizes
Samsung’s 12,000mAh battery prototype uses a dual-cell design

Samsung is reportedly testing high-capacity silicon-carbon (Si-C) smartphone batteries, including 12,000mAh and 18,000mAh prototypes. A leaked document suggests Samsung SDI is refining cell stacking designs and battery management software to improve reliability, thermal performance, and efficiency. The company has taken a cautious approach to new battery technologies since the Galaxy Note 7 incidents in 2016 and is still evaluating Si-C batteries before introducing them commercially. If development succeeds, thinner high-capacity cells could eventually power future flagship smartphones and foldable phones without increasing device thickness.

Samsung SDI Testing Next-Gen Silicon-Carbon Batteries for Phones

The South Korean tech firm is testing silicon-carbon smartphone batteries, including 12,000mAh and 18,000mAh prototypes, according to information shared in a post on X by user Schrödinger (@phonefuturist). The post also claims that a larger 20,000mAh silicon-carbon battery previously under evaluation failed durability testing after about 960 charge cycles.

Samsung SDI is testing 12K, 18K mAh Si/C cells. The 20K failed at 960 cycles. Race is on. 👀

Full PDF available, Samsung tracking system didn't work much. Anyways it's not free. pic.twitter.com/D8NDy4weNw
— Schrödinger (@phonefuturist) March 9, 2026

Silicon-carbon batteries can store more energy than lithium-ion cells by using a silicon-based anode instead of graphite, allowing higher capacity without significantly increasing battery size. Several modern smartphone models, especially from Chinese firms, have already adopted this technology.

Leaked testing details suggest that the 20,000mAh unit used a dual-cell design combining a 12,000mAh primary cell measuring about 6.3mm thick with a secondary 8,000mAh cell measuring roughly 4mm. The prototype reportedly did not meet Samsung's durability targets during testing, prompting the company to continue development with smaller silicon-carbon battery configurations.

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One prototype reportedly offers a total capacity of 12,000mAh and uses a dual-cell structure consisting of a 6,800mAh cell measuring around 4.7mm and a 5,200mAh cell measuring approximately 3.2mm. The intended combined thickness is under about 9.3mm, although some test samples reportedly exceeded that limit.

Samsung is also reportedly testing an 18,000mAh configuration built using three cells rated at 6,699mAh, 6,000mAh, and 5,257mAh, with thicknesses of roughly 4.2mm, 3.9mm, and 3.28mm, respectively. The target stacked thickness is about 12.3mm, but additional thermal interface layers between the cells have reportedly pushed some prototypes to around 12.8mm.

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The testing programme reportedly aims for a lifespan of around 1,500 charge cycles for the 12,000mAh and 18,000mAh batteries, although development is still ongoing. The 12,000mAh version is said to prioritise stability and could theoretically deliver around 20 to 25 hours of screen-on time on a smartphone connected to both mobile data and Wi-Fi.

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Further reading: Samsung, Samsung DPI, Samsung Battery

Sucharita Ganguly

Email Sucharita Ganguly

Sucharita is a writer with Gadgets 360 and is mostly found playing with her cat in her free time. She has previously worked at breaking news desks across organizations. Powered by coffee, The Beatles, Bowie, and her newfound love for BTS, she aims to work towards contributing to a better media environment for women and queer folk. More