Achieving Robust Macroscale Superlubrication on Steel Surfaces via Solid‐Liquid Synergy of Ionic Liquid‐Intercalated MXenes

Achieving superlubrication in engineering steel interfaces holds tremendous potential for reducing energy loss and mechanical wear. Nevertheless, maintaining stable superlubrication under high contact stress and sliding speed remains highly challenging. Herein, a novel MXenes@IL composite was synthesized by intercalating an ionic liquid (IL) between MXene nanosheet layers, and then dispersed in a 1,4‐butanediol solution as an additive. This system can sustain superlubrication (µ ≈ 0.002) for 5 h under extreme conditions (300 N load, 0.461 m/s sliding speed) and drastically shortens the run‐in period to approximately 240 s. Comprehensive tribofilm analysis and molecular dynamics simulations revealed that the stable superlubrication mechanism arises from the formation of carbon‐based tribofilms via interfacial tribochemical reactions and the establishment of a low‐shear lubrication layer. Specifically, IL intercalation enhanced MXene interlayer slip, reducing initial shear stress through solid‐liquid synergistic effects, while the released IL promoted tribochemical reactions to form a carbon‐based tribofilm, accelerating the run‐in process. Additionally, anions were directly involved in interfacial tribological reactions, contributing to phosphate‐containing tribofilm formation. This work provides a novel and promising strategy for designing advanced lubricating materials to achieve durable superlubrication under harsh conditions.