Superior lubrication and electrical stability of graphene as highly effective solid lubricant at sliding electrical contact interface

Graphene with excellent mechanical, tribological and electrical properties has enormous potential as solid lubricant at sliding electrical contact interfaces. Here, ultra-low friction (the coefficient of friction is about 0.028), ultra-high current stability (the coefficient of variation is as low as 4.74%) and effective wear-resistance properties (keep stable under contact pressure of 5.93 GPa for 10,000 cycles) of graphene as solid lubricant are found at electrical contact interface under the combined effect of the load and current. The high current stability and ultra-low friction could attribute to stable electric contact and conductive quality at the interface due to the high flexibility and carrier mobility of graphene based on the molecular dynamic simulations and atomic stick-slip behavior calculations. The high wear resistance at sliding electrical contact interface derives from the ultra-strong mechanical strength of graphene for combined effect of electricity and load. Our studies found that graphene with ultra-low friction, ultra-high conductivity, flexibility, and mechanical strength is unique as solid lubricant in various devices with sliding electrical contact interfaces.