Clean energy carrier hydrogen requires improved containment methods that prevent H2 embrittlement and permeation within H2 infrastructure owing to high-pressure H2. Our study evaluated polymer nanocomposite (PNC) coatings as potential barrier coatings, assessing materials and coating designs to optimise performance, durability, and large-scale manufacturability. Our multifaceted research methodology includes the following: 1) Literature review on the topic of H2 permeability/permeation and embrittlement, identifying gaps in knowledge concerning how PNCs affect these processes. 2) Molecular dynamics simulations to analyse H2 diffusivity in different PNC compositions (298- 353 K temperature range, 1- 100 bar pressure range). 3) Finite element analysis (FEA) to assess the stresses and strains at the interface of a PNC coating and H2 infrastructure under operational conditions. Our meta analysis of 12 published studies indicates that a PVDF-graphene nanocomposite with 1.0 wt% graphene filler (PVDF-1.0 wt% GNC) reduced H2 permeability by 31.6% compared to non-filled PVDF. Furthermore, we identified several other materials, such as MXene nanosheets and Krytox liquid coatings, that provide exceptional H2 barrier properties under both electrochemical and high-pressure-stressed environments. However, adhesion failure remains a critical issue for PNCs exposed to corrosive and cyclic-loading conditions. For instance, conventional polymer coatings completely degraded upon exposure to H2S at 8 MPa. In addition, the substrate material significantly affects PNC performance; for example, X52 and X70 steels exhibited different interfacial behaviours with PNC coatings. Based on computational analysis, temperature dependence of diffusivity was observed in HDPE and EVOH but remains unexplored for most PNCs. Industrial failure analyses indicate that conventional coating systems were highly susceptible to failure when used in aged H2 infrastructure components. Therefore, more resilient PNC coating materials are needed to ensure the long-term integrity of existing infrastructure and to facilitate the expansion of the H2 economy through the development of new H2 infrastructure. Overall, this research demonstrates the promise of PVDF-graphene and MXene-based PNCs for mitigating H2 permeability and identifies several key research areas to improve PNC performance over the long term. These findings will contribute to safer H2 transportation and storage, thereby promoting the development and adoption of carbon-neutral H2 energy technologies.

Clean energy carrier hydrogen requires improved containment methods that prevent H2 embrittlement and permeation within H2 infrastructure owing to high-pressure H2. Our study evaluated polymer nanocomposite (PNC) coatings as potential barrier coatings, assessing materials and coating designs to optimise performance, durability, and large-scale manufacturability. Our multifaceted research methodology includes the following: 1) Literature review on the topic of H2 permeability/permeation and embrittlement, identifying gaps in knowledge concerning how PNCs affect these processes. 2) Molecular dynamics simulations to analyse H2 diffusivity in different PNC compositions (298- 353 K temperature range, 1- 100 bar pressure range). 3) Finite element analysis (FEA) to assess the stresses and strains at the interface of a PNC coating and H2 infrastructure under operational conditions. Our meta analysis of 12 published studies indicates that a PVDF-graphene nanocomposite with 1.0 wt% graphene filler (PVDF-1.0 wt% GNC) reduced H2 permeability by 31.6% compared to non-filled PVDF. Furthermore, we identified several other materials, such as MXene nanosheets and Krytox liquid coatings, that provide exceptional H2 barrier properties under both electrochemical and high-pressure-stressed environments. However, adhesion failure remains a critical issue for PNCs exposed to corrosive and cyclic-loading conditions. For instance, conventional polymer coatings completely degraded upon exposure to H2S at 8 MPa. In addition, the substrate material significantly affects PNC performance; for example, X52 and X70 steels exhibited different interfacial behaviours with PNC coatings. Based on computational analysis, temperature dependence of diffusivity was observed in HDPE and EVOH but remains unexplored for most PNCs. Industrial failure analyses indicate that conventional coating systems were highly susceptible to failure when used in aged H2 infrastructure components. Therefore, more resilient PNC coating materials are needed to ensure the long-term integrity of existing infrastructure and to facilitate the expansion of the H2 economy through the development of new H2 infrastructure. Overall, this research demonstrates the promise of PVDF-graphene and MXene-based PNCs for mitigating H2 permeability and identifies several key research areas to improve PNC performance over the long term. These findings will contribute to safer H2 transportation and storage, thereby promoting the development and adoption of carbon-neutral H2 energy technologies.