Eliminating the Galvanic Corrosion Effect of Graphene Coating by an Accurate and Rapid Self-Assembling Defect Healing Approach

The structural defects on graphene grown on a metal substrate via chemical vapor deposition can readily stimulate severe galvanic corrosion phenomena. For any defect passivation method that can be technologically promising for superior corrosion-resistant graphene coatings, efficiency and accuracy are two critical but still challenging requirements. In this work, the authors design a rapid processing method (within just 15 min) that can accurately heal various structural defects of different types and sizes on graphene coating, where the hydrophobic 1 H ,1 H ,2 H ,2 H -perfluorooctanethiol (PFOT) molecules are self-assembled onto the defect sites. The surface morphologies, atomic bonding states, and defect-healing mechanism are deeply understood by comprehensive experimental characterizations and first-principles calculations. Both weak physical PFOT-pristine graphene bonding and strong covalent PFOT-defect bonding are two microscopic factors that enhance defect healing efficiency and accuracy. Spatially resolved electronic and electrochemical measurements show that the defect-healing not only effectively suppresses galvanic corrosion phenomena during both short-term and long-term tests, but also well preserves the superior electronic conductivity of pristine graphene. The defect healing strategy proposed here can find its wide potential applications in the fields like electro-industry, coating, and sensors that require the graphene coatings having both superior corrosion resistance and electronic property.