Phase engineering of two-dimensional MoS2: from structural evolution to tribological applications

Abstract

Precise control of structural phase transitions is essential for optimizing the functional performance of two-dimensional MoS₂. Although MoS₂ is a premier solid lubricant owing to its layered architecture and low-shear characteristics, its tribological efficiency is strongly dependent on environmental conditions and the material's intrinsic phase state. This review systematically surveys recent advances in MoS₂ phase engineering in the context of tribological behavior and friction interface evolution, emphasizing mechanisms driven by ion/charge injection and external physical stimuli such as electric fields and mechanical strain. We examine how the metallic phase transition modifies the electronic structure and interfacial interactions, thereby fundamentally altering lubrication behavior through changes in interlayer sliding and friction energy dissipation. Particular attention is given to emerging strategies, such as elemental doping and heterointerface construction, that stabilize functional phases and enable the formation of self-repairing tribological structures. Moreover, we discuss friction regulation mechanisms associated with interlayer sliding behavior and structural evolution at sliding interfaces. Finally, we highlight the integration of multiscale characterization techniques with theoretical simulations as indispensable tools for elucidating non-equilibrium phase evolution and the structural dynamics occurring at friction interfaces. This review provides a rigorous theoretical foundation and strategic guidance for the design of next-generation, phase-tailored 2D lubricants capable of stable operation under extreme aerospace and industrial environments.