Tungsten disulfide (WS₂) nanomaterials have emerged as highly effective lubricant additives, leveraging their capacity to mitigate friction and wear, enhance operational performance, and prolong the durability of sliding components. This review provides a comprehensive overview of recent advances in the preparation methods of WS₂ nanomaterials and their applications in tribology. It evaluates how preparation techniques, surface modifications, and composite architectures govern their friction-reducing properties, elucidating the mechanism underlying their superior tribological performance. WS₂ nanomaterials are reported to exhibit superior tribological properties, positioning them as prominent research frontiers in materials science and tribological engineering. Their industrial implementation holds substantial potential for generating both economic benefits and societal value through enhanced energy efficiency and extended component lifespan. Despite the promising potential of WS₂ nanomaterials in next-generation lubrication technologies, significant challenges hinder their widespread practical application. These include understanding how defect dynamics impact lubrication performance, addressing the inherent limitations of polar oil matrices, the lack of comprehensive knowledge regarding real-time service behavior under operational conditions, and their restricted applicability in extreme environments. Overcoming these critical barriers is crucial for fully realizing the sustainable potential of WS₂ nanomaterials in advanced lubrication solutions.

Friction and wear are unavoidable in mechanical movement. The use of lubricants with nano-additives can effectively reduce friction and wear, which is of great significance to saving energy and protecting the environment. At present, great progress has been made in the scientific research and industrial application of nano-additives for lubricants. This paper mainly introduces the types of nano-additives for lubricants (such as carbon nanomaterials, nano-metals, nano-oxides, sulfides, complexes, polymers, etc.), the tribological properties of lubricants with different components of nano-additives, and the lubrication mechanisms of the nano-additives (including tribofilm formation, rolling ball bearing effect, repairing effect, polishing effect, and synergistic effect). It also deals with the dispersion of nano-additives in lubricants and the influences of their particle size and microstructure on the tribological properties of lubricants. This review outlines the performance requirements of nano-additives in different lubrication states, discusses the use of nano-additives in challenging working conditions, and identifies various industrial oil nano-additives with reference to the appropriate options in diverse working environments. Furthermore, the existing problems of nano-additives and their application prospects are summarized. This review, hopefully, would help to shed light on the design and synthesis of novel high-performance nano-additives and promote their application in engineering.