Challenges of MXene-based nanomaterials for tribological applications

Introduction

MXenes are two-dimensional transition metal carbides and nitrides which have gained significant importance for their potential in improving lubrication and minimizing wear in mechanical systems. The increasing emphasis on energy efficiency and environmentally friendly solutions has created a promising need for MXene-based materials in the field of tribology. Their unique layered structure, surface chemistry, and mechanical robustness enables improved tribological behavior, making them suitable for a wide range of applications.

Figure-1 MXenes precursors and their synthesis [2]

Tribological challenges of MXenes

MXenes have shown great promise in tribological applications but there are several challenges that could hinder their practical use. These includes high synthesis costs and limited scalability, poor environmental stability, and difficulties in achieving uniform dispersion in lubricants. Additionally, the underlying lubrication mechanisms are not fully understood, and most studies don’t test MXenes under harsh or long-term conditions. The influence of surface terminations and achieving rapid, stable superlubricity also remain key areas for further research. Addressing these challenges is essential for translating MXene-based materials into real-world mechanical systems.

Table-1 Tribological challenges of MXenes and potential solutions

Challenge	Description	Potential Solutions
Scalability & Cost of Synthesis	Complex, costly, and hazardous (e.g., , hydrofluoric acid (HF)-based) synthesis limits large-scale production.	Develop greener, cost-effective methods (e.g., lithium fluoride (LiF) and hydrochloric acid (HCl), microwave-assisted etching).
Environmental Stability	Degradation in humid/corrosive environments affects long-term performance.	Use protective coatings, functionalization, and moderate oxidation to improve durability.
Poor Dispersion in Lubricants/Composites	Agglomeration leads to uneven distribution and inconsistent lubrication performance.	Apply surfactants, surface modifiers like tetradecylphosphonic acid TDPA or in-situ HS growth for better dispersibility.
Limited Understanding of Mechanisms	Tribological behavior at nanoscale is not fully understood, hindering optimization.	Use molecular dynamics simulations, in situ microscopy for mechanistic insights.
Performance Under Harsh Conditions	Most studies use low temp/load/time; real-world durability remains unproven.	Conduct extensive testing under extreme conditions and longer durations.
Influence of Surface Terminations	Effects of termination species on lubrication properties are not thoroughly studied.	Further investigate theoretically and experimentally (e.g., hydrophilicity-dependent friction).
Achieving Fast Superlubricity	Superlubricity achieved, but often after long running-in times, especially in liquids.	Improve surface design and explore mechanisms for faster superlubricity (like in graphene oxide).

Potential solutions for future

Future research on MXene-based materials is expected to prioritize the development of multifunctional nanomaterials focused on tribological, mechanical properties. This should enable the advanced systems with capabilities such as self-healing and sensing abilities. A strong emphasis will also be placed on sustainable and eco-friendly synthesis methods aiming to reduce environmental impact while improving commercial scalability. Another key focus area involves the use of advanced characterization techniques like in situ microscopy and spectroscopy to gain deeper insights into atomic-scale tribological behaviors of MXenes. Further enhancing the performance and durability of MXene coatings through innovative fabrication techniques such as electrophoretic deposition and electrospraying will be critical for extending service life in real-world applications. Finally, efforts will be directed at expanding MXene’s role in various industries by customizing their compositions and surface chemistries to suit demanding conditions, such as high-temperature, marine, or biomedical environments, while also exploring their integration into next-generation energy harvesters and structural composites.