SK Group Chairman Chey Tae-won’s younger brother Chey Jae-won will take the post as the co-CEO of SK On, the group’s electric vehicle battery unit.

According to SK on Friday, it held a board of directors meeting and appointed the junior Chey as the co-CEO. Chey Jae-won will lead SK On together with current CEO Jee Dong-seob.

This is a return to management for Chey eight years after he stepped down from all posts in 2013 when he was sentenced to 3 1/2 years in prison for embezzlement. After being released on parole in 2016, he faced employment restrictions for five years, which ended this October.

Chey, who holds a bachelor’s degree in physics from Brown and a master’s degree in materials science from Stanford, was deeply involved in SK Group’s burgeoning battery business. He identified the potential of the electric vehicle business from early on and recommended to his older brother that he make aggressive investments in the field.

Despite his employment restrictions, the junior Chey has had a presence around the company, attending the group’s key battery events in recent years. He was present when his brother met with Hyundai Motor Group Chairman Chung Euisun last year at SK Innovation’s battery plant in Seosan, South Chungcheong Province. He also accompanied the SK chairman in his US trip earlier this year to check on the group’s investment status there. He also participated in the groundbreaking ceremonies of SK Innovations’ battery plants in Hungary and the US state of Georgia.