Achieving structural superlubricity in graphitic samples of macroscale size is particularly challenging due to difficulties in sliding large contact areas of commensurate stacking domains. Here, we show the presence of macroscale structural superlubricity between two randomly stacked graphene layers produced by both mechanical exfoliation and chemical vapour deposition. By measuring the shifts of Raman peaks under strain we estimate the values of frictional interlayer shear stress (ILSS) in the superlubricity regime (mm scale) under ambient conditions. The random incommensurate stacking, the presence of wrinkles and the mismatch in the lattice constant between two graphene layers induced by the tensile strain differential are considered responsible for the facile shearing at the macroscale. Furthermore, molecular dynamic simulations show that the stick-slip behaviour does not hold for incommensurate chiral shearing directions for which the ILSS decreases substantially, supporting the experimental observations. Our results pave the way for overcoming several limitations in achieving macroscale superlubricity using graphene.

The development of three-dimensional (3D) porous graphitic structures is of great interest for electrochemical sensing applications as they can support fast charge transfer and mass transport through their extended, large surface area networks. In this work, we present the facile fabrication of conductive and porous graphitic electrodes by direct laser writing techniques. Irradiation of commercial polyimide sheets (Kapton tape) was performed using a low-cost laser engraving machine with visible excitation wavelength (405 nm) at low power (500 mW), leading to formation of 3D laser-induced graphene (LIG) structures. Systematic correlation between applied laser dwell time per pixel (“dwell time”) and morphological/structural properties of fabricated electrodes showed that conductive and highly 3D porous structures with spectral signatures of nanocrystalline graphitic carbon materials were obtained at laser dwell times between 20 and 110 ms/pix, with graphenelike carbon produced at 50 ms/pix dwell time, with comparable properties to LIG obtained with high cost CO₂ lasers. Electrochemical characterization with inner and outer sphere mediators showed fast electron transfer rates, comparable to previously reported 2D/3D graphene-based materials and other graphitic carbon electrodes. This work opens the way to the facile fabrication of low-cost, disposable electrochemical sensor platforms for decentralized assays.