Android smartphone manufacturers are exploring new battery technologies that could significantly increase device autonomy, with some models potentially reaching 10,000 mAh capacities. According to reports from Digital Chat Station on Weibo, a major Chinese manufacturer, possibly Xiaomi, is testing batteries with capacities between 9000 and 10,000 mAh for future high-end models. These batteries are being developed using rigid steel casings combined with stacked-cell technology, an approach inspired by Apple's use of aluminum and later steel in the iPhone 16 Pro, 17 Pro, and 18 Pro series. Traditional soft-pouch batteries require internal empty space to accommodate natural swelling, limiting total capacity and thermal dissipation. In contrast, rigid casings allow for more compression of cells, improved thermal dissipation, and safer maximization of internal volume. The Xiaomi 18 Pro Max, for example, features an 8500 mAh battery despite its large camera modules and secondary rear screen. The Redmi Note 17 Pro Max reaches 10,000 mAh in China and about 9200 mAh in Europe, with a 100 W charge and more than three days of use announced. The integration of silicon-carbon batteries and stacked-cell technology allows better use of available volume and reduces internal resistance. However, the weight remains a challenge, as steel adds significant mass. The goal is to house a 10,000 mAh battery alongside multiple camera modules while keeping the device's thickness under 9 mm and weight under 230 g. For professional mobility, the switch to high-density batteries could optimize the total cost of ownership by reducing failure rates, improving thermal stability, and slowing chemical degradation. However, the increased weight may require compromises in form factor. Samsung is also revising its approach, with leaks suggesting 5200 mAh for the Galaxy S27 Pro and 5700 mAh for the S27 Ultra, though these values are still below Chinese records.