Soonho Ahn joined (AAPL) Apple in December as global head of battery developments, after working as a senior vice president at Samsung SDI since 2015, according to his LinkedIn profile. At Samsung SDI, Ahn led development of lithium battery packs and worked on “next-generation” battery technology, the profile says.

Apple and Ahn didn’t respond to requests for comment. (SSNLF) Samsung is the largest shareholder of Samsung SDI and the company’s biggest customer, according to data compiled by Bloomberg.

Apple has used batteries from Samsung SDI to power its own products in the past. The iPhone maker has been trying to reduce reliance on third-party components, and the notable battery technology hire suggests it may be doing the same for batteries. Apple has been working on its own MicroLED display technology for future devices, which would help wean itself off Samsung in other areas. It’s also increasingly building its own processors and is investigating the development of its own cellular modems.

Apple has also been in talks to buy cobalt, a key component of battery packs, directly from miners. As device makers release products with similar functionality, differences in key features like battery life and performance are becoming more important, and Apple is seeking a competitive advantage in those areas.

Samsung SDI is also seeking sources of cobalt.