Mechanism of Multilayer Graphene/Ionic Liquid Synergistic Regulation of Interface State under Current-Carrying Friction

Herein, improving the conductivity of the lubricant itself is the main idea behind current-conductive lubricant designs. However, as per previous studies, the interface state has a more dominant influence on the interface conductivity than the conductivity of the lubricant. Therefore, improving the interface state is a more direct and effective way to improve the interface conductivity. In this study, improving the interface state is the primary idea underlying the design of a conductive lubricant. Multilayer graphene/ionic liquid (MG/IL) composites with excellent interfacial adsorption properties are prepared using IL non-covalently modified graphene. Subsequently, corresponding conductive greases are synthesized using MG, IL, and MG/IL as additives. The lubricating and conductive properties of these greases are characterized by performing current-carrying friction tests. In the results, it is shown that when MG/IL is used as an additive, the grease exhibits excellent lubricating performance and the lowest average contact resistance. This finding is primarily attributed to the MG and IL in MG/IL acting synergistically to improve the interface state significantly, which decreases the contact resistance and increases the conductivity of the friction interface. In this work, a novel idea is provided for the design of conductive lubricants. Multilayer graphene/ionic liquid (MG/IL) composites are prepared using IL non-covalently modified graphene. Current-carrying friction test results show that when MG/IL is used as an additive to grease, it exhibits excellent lubricating performance and the lowest average contact resistance. This finding is primarily attributed to the MG and IL in MG/IL acting synergistically to significantly improve the interface state.image (c) 2024 WILEY-VCH GmbH