From a Passive Barrier to Smart Protection: Progress, Challenges, and Perspectives of MXene-Based Anticorrosive Coatings

MXene-based anticorrosive coatings have attracted increasing attention because the lamellar structure, tunable surface terminations, and high aspect ratio of MXenes can improve the barrier performance, interfacial compatibility, and functional response in polymer coatings. This review summarizes recent progress in MXene-enabled corrosion protection from a mechanism-oriented perspective. The discussion is organized according to the dominant working principles of reported systems, including physical barrier protection, active inhibition/passivation, self-healing behavior, intelligent sensing/response, and structural or interfacial engineering. Particular attention is paid to the dual roles of MXene conductivity and oxidation. These features may support charge redistribution, interfacial passivation, or smart response, but they may also induce galvanic coupling, nanosheet degradation, and long-term instability when they are not properly controlled. In addition to summarizing representative coating systems, this review discusses the limitations of direct cross-study electrochemical comparisons and emphasizes the need to report coating thickness, MXene loading, substrate, electrolyte, exposure duration, and testing protocol. Key challenges include scalable and green MXene synthesis, oxidation control, suppression of galvanic corrosion, standardized durability assessment, and translation of short-term laboratory demonstrations into service-relevant coating designs. This review aims to provide a mechanistic basis for developing durable, safe, and engineering-compatible MXene-based anticorrosive coatings.