A discussion is happening around why iPhone, Galaxy, and Pixel phones still have relatively small batteries.

Despite competitors' strides in battery tech, flagship phones like the Galaxy S25 Ultra and iPhone 17 Pro Max hover around 5,000 mAh. What is the hold-up? While other manufacturers are increasing battery capacity, these brands seem stagnant, prompting an investigation.

Is physical size a constraint?

Form factor is a considerable factor in limiting battery size. The trend toward thinner phones is a contributing element. The iPhone Air, at just 5.6 mm, has a battery that only slightly exceeds 3,000 mAh.

The RedMagic 11 Pro, approximately 8 mm thick, has a battery with 2.5 times more capacity and includes wireless charging. This illustrates a design choice that many consumers might prefer.

Chinese manufacturers use silicon-carbon batteries with greater energy density. However, regulations also play a role in limiting battery size for companies outside of China.

Strict international shipping rules classify lithium-ion batteries exceeding 20 watt-hours (roughly 5,400 mAh) as Class 9 dangerous goods.

This results in increased shipping expenses, specialized packaging, and extensive documentation for phones exceeding this capacity.

Chinese companies bypass this by using a dual-battery configuration.

Using two cells, each under the 20 watt-hour limit, allows them to be classified as "small lithium-ion batteries," reducing logistical burdens.

Samsung, Apple, and Google have been hesitant to adopt this method due to the production line changes and expense it would require. This leads to the consideration of silicon-carbon batteries.

Silicon-carbon batteries utilize a graphene anode with high silicon content. Silicon's capacity to store charged particles exceeds lithium's by a factor of ten, theoretically enabling a tenfold increase in battery capacity with a pure silicon anode, but there are complications.

Silicon expands significantly during energy storage, potentially by 300%. Such expansion within a smartphone could be hazardous.

Even with lower silicon content (10-15%), swelling can still occur, potentially fracturing the anode and causing irreversible battery damage.

Stabilization methods, including coatings, chemical mixtures, and nanostructures, can mitigate these issues.

Chinese manufacturers lead in this technology because of less stringent domestic regulations. Honor has developed fourth-generation silicon-carbon technology, and the OnePlus 15 features a 15% silicon content in its graphene anode.

When will silicon-carbon batteries appear in iPhones and Galaxy devices?

Adoption is not imminent due to financial factors. Samsung, Apple, and Google have invested heavily in conventional lithium-ion production and would incur significant costs by switching to silicon-carbon.

Silicon-carbon batteries necessitate new equipment, materials for obtaining high-purity silicon nanoparticles, and extensive regulatory approvals. This poses a substantial undertaking for limited gains.

Consequently, these major companies are focused on optimizing traditional lithium-ion batteries through software enhancements.

Silicon-carbon batteries need a different battery management system with unique voltage curves, charging behaviors, and degradation profiles. This would require updated firmware, charging chips, thermal management, and packaging, adding to the cost.

Following the Note 7 incidents, Samsung is cautious about new technology.

Apple typically conducts extensive internal testing before implementing major changes. This suggests that smaller batteries and average battery life may persist in iPhones, Galaxies, and Pixel phones for some time. However, solid-state batteries are a possibility.

When will iPhones have 7,500 mAh batteries?

A 2017 report suggested Samsung would use solid-state batteries within two years. Current estimates point to a gradual shift toward silicon-carbon between 2027 and 2030.

Adoption of silicon-carbon tech by Samsung, Apple, and others will be gradual. Initial capacity improvements will likely be around 5-10%, resulting in a 5,500 mAh battery in the next Galaxy Ultra. Subsequent iPhone Pro Max models may reach 6,000 mAh.

Meanwhile, Chinese companies are expected to advance high silicon content batteries within five years, potentially achieving 10,000 mAh capacities, although not in Apple or Samsung devices.