▎ 摘　　要

NOVELTY - The slip ring unit has a slip ring and a brush, where one of the slip ring and the brush comprises a composite material comprising graphene and metal, where the graphene content is 0.1-5 wt.% and the metal content is 90 wt% of the total weight of the composite material. The composite material is provided as a coating on the metal carrier. The metal is one of copper, silver, bronze, or stainless steel and is free of graphite and carbon black. USE - Slip ring unit for conducting current to or from rotating shaft of electrical machines. Uses include but are not limited to electric motors, hybrid motors, and electric motors. ADVANTAGE - The slip ring unit has low friction and wear-limiting properties. The brush is free of graphite and/or carbon black, and has extended lifetime. The dust creation is reduced and thus the risk of clogging or short circuiting is reduced or avoided. The electrical conductivity of the metal is not altered due to the outstanding electrical properties of graphene and is improved compared to carbon brushes containing graphite. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a slip ring unit.