Macroscale solid superlubricity from the perspective of tribochemistry

Superlubricity, featuring near-zero friction, has attracted much attention due to its effectiveness in addressing energy crises. The underlying mechanism of solid superlubricity is incommensurate contact. Nowadays, relying on incommensurability and weaken size effect by reducing the contact area is an effective strategy for constructing macroscale solid superlubricity. However, the lack of a more profound understanding of the entire process of constructing superlubric interfaces is not conducive to advancing the progress of practical applications. Tribochemistry serves as the main thread of the process, leading the structural evolution behavior between steady states. It is powered by friction behavior to grow the lubricating phase that constructs the superlubric interface through physical and chemical reactions. This review, from the perspective of tribochemistry, delves into the mechanisms of energy dissipation and the evolution of interface structures involved in various lubrication forms. It demonstrates that the macro-superlubricity benefits from the macroscopic expression (lubricating layers) of microscale lubricating phases. Furthermore, we also introduce the novel applications of superlubricity in advanced manufacturing technologies. Meanwhile, the groundbreaking advancements in macro-superlubricity research are systematically highlighted. This review not only effectively complements the commentary on macroscale solid superlubricity but also provides critical insights for extending solid superlubricity towards practical macroscale applications.