Apple is working on a custom battery design that will be developed in-house, according to a report. The iPhone maker is said to be looking to increase the battery life of its products by changing the composition of its batteries. South Korean news publication ET News reports that Apple’s rumoured battery technology improvements aren’t expected to make their way to the company’s products for the next couple of years, suggesting the development of the purported battery improvements is not at an advanced stage.

According to the report (in Korean) Apple is working on an improved battery technology for its upcoming products that will include a “next-generation battery” (translated from Korean). The company is said to be directly involved in the process of designing the new technology, from the development of the cathode and the necessary components and materials, to the use of different materials for improved performance.

Apple is reportedly considering the use of a new composition for the cathode material, along with the use of carbon nanotubes (CNTs) as a conductive material — both of these could offer improved performance compared to the company’s existing battery components.

Meanwhile, the company is also working on using different materials for the anode material used in the battery, as per the report. Instead of graphite, Apple is said to be considering using silicon — despite the tendency of silicon to expand while charging or discharging — as the company has reportedly found a way to mitigate the expansion issue.

The company is said to have been working on the technology since at least 2018, including the recruitment of an executive from Samsung SDI, the South Korean firm’s battery and electronics division a year later.

While there’s no word from Apple on when we can expect to see the purported battery improvements and which devices will be equipped with the next-generation battery design, the report claims that Apple is looking to launch devices with the new battery technology within the next two years, which means we could see devices — offering improved battery life over their predecessors — as early as 2025.