Interfacial nano-engineering of MXene-integrated carbon fiber composites for safer type V hydrogen tanks

The fabrication of Type V composite overwrapped pressure vessels (COPVs) for compressed hydrogen storage necessitates comprehensive material-level understanding of how fibre orientation and nanofiller concentration jointly determine structural integrity, gas-barrier performance and thermal stability. This research investigates MXene-integrated unidirectional (UD) and woven carbon fibre/epoxy composites as promising materials for Type V COPV manufacturing through a unified framework combining laminate fabrication, energy-dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile testing, scanning electron microscopy (SEM), non-destructive evaluation (NDE), and finite element modelling (FEM). The incorporation of MXene nanoflakes at a loading of 0.5 wt% yielded peak improvements of 18.39% and 22.07% in tensile strength for UD and twill laminates, respectively, while stiffness measurements emphasized a concentration-mediated effect ascribed to MXene agglomerations at higher loadings. TGA and DSC confirmed enhanced thermal stability with a 10 °C increment in glass transition temperature, demonstrating an increased degree of crosslinking. Hydrogen permeation testing through MXene-integrated UD laminates achieved a steady-state diffusion and sorption stage after repeated pressurization events as the permeation values varied marginally between 18.2 and 18.8 mL m^-2 day^-1 atm^-1, confirming a converged steady-state condition. Linear regression achieved R ² values of 0.9617 and 0.84 for tensile strength and stiffness, respectively. MXene-incorporated UD composites highlighted their capability to avoid early leakage and achieved an equilibrium diffusion state under pressurized loading, suggesting their potential to carry load and serve as hydrogen barrier materials, an essential requirement for linerless Type V hydrogen storage pressure vessels.