Technologies are generally described for a system and process effective to coat a substance with graphene. A system may include a first container including graphene oxide and water and a second container including a reducing agent and the substance. A third container may be operative relationship with the first container and the second container. A processor may be in communication with the first, second and third containers. The processor may be configured to control the third container to receive the graphene oxide and water from the first container and to control the third container to receive the reducing agent and the substance from the second container. The processor may be configured to control the third container to mix the graphene oxide, water, reducing agent, and substance under sufficient reaction conditions to produce sufficient graphene to coat the substance with graphene to produce a graphene coated substance.