Abstract
Hydrogen (H2) energy has emerged as a promising alternative in the automotive sector to replace fossil fuel; however, its storage with volumetric efficiency remains a challenge. The latest type IV storage vessel featuring a polymeric liner with composite overwrap incurs hydrogen saturation, which eventually causes failure. To prevent the H2 dissolution in the liner, we have developed a barrier coating comprised of polyurethane/epoxy semi-interpenetrating network (S-IPN) combined with hyperbranched polyglycerol grafted MXene (h-MXene). The hyperbranched structure facilitated the dispersion of MXene in the coating solution by enhancing the exfoliation and improved the polymer filler interaction by forming covalent and H-bonding through end-terminal hydroxyl groups. Leveraging the dense network of S-IPN combined with the dispersed layer structured h-MXene significantly increased the tortuosity of the spray-coated barrier film applied to the nylon 6 liner. The coating exhibited a 90 % reduction in the H2 gas permeability at only 2 wt% h-MXene concentration, which further improved to above 98 % at 10 wt% loading. Additionally, the h-MXene considerably improved the adhesion with the liner even in a highly stretched condition, signifying the durability of the coating under cyclic pressurization and depressurization of the storage vessel.
| Original language | English |
|---|---|
| Article number | 119427 |
| Journal | Carbon |
| Volume | 228 |
| DOIs | |
| State | Published - Sep 2024 |
Funding
This work was supported by the Regional Leading Research Center Program (2019R1A5A8080326) through the National Research Foundation (NRF) funded by the Ministry of Science and ICT of Republic of Korea. And this work was partly supported by the ITECH R&D program of MOTIE/KEIT [project No. 20010509]. administration, Roles/Writing - original draft, Writing - review & editing. The morphology of the MXene and h-MXene nanofillers obtained by FE-SEM is shown in Fig. 4a\u2013b. The elemental mapping showed the existence of Ti, C and O elements for both cases. Although a minute reduction in the flake size was observed after the functionalization, the average lateral size of the flakes was bigger than 2 \u03BCm even in the case of h-MXene. The h-MXene nanosheet appeared to be rough showing higher surface wrinkles than that of the MXene nanosheet, indicating the successful functionalization of h-MXene. Besides, the EDS mapping of the FE-SEM scans also showcased a higher C and O contents when the MXene was treated with glycidol supporting the grafting of hyperbranched polyglycerol (Table S1). The AFM height image (Fig. 4c) also showed a similar flake size as noted in the FE-SEM analysis. The height vs. distance curve is given as an insert in the AFM image. The average thickness of the flake was \u223C3 nm, indicating a few layers of h-MXene. The HR-TEM image (Fig. 4d) also displayed a large 2D layers structure of h-MXene with clearly visible fringes. The morphology of h-MXene suggested that the ring-opening polymerization of glycidol on the MXene surface facilitated the exfoliation, with minimum reduction in the flake size.The WAXD pattern of the solvent-casted nanocomposite films is shown in Fig. 5c. A broad peak at 2 \u03B8 = 20\u00B0 appeared for all the nanocomposite samples similar to the unfilled S-IPN due to the coexistence of crystalline and amorphous regions of TPU in the S-IPN network [50]. The h-MXene filled films exhibited another diffraction peak at around 5\u00B0 (shown by arrow) which was absent in the unfilled sample. This peak indicated the (002) plane of the h-MXene flake in the nanocomposite, and thus the peak intensity increased with the filler loading. Note that the 2 \u03B8 range of (002) diffraction peak of h-MXene marginally shifted to lower diffraction angle after incorporating it in the S-IPN. For the untreated MXene-filled samples, two diffraction peaks were detected at around 5 and 9\u00B0 (shown by a dotted line) unlike h-MXene. The etched untreated MXene (before incorporation into the S-IPN matrix) exhibited the diffraction peak at 6.7\u00B0. After mixing with the S-IPN, a part of the MXene nanofiller exfoliated shifting the (002) diffraction peak to 5\u00B0 whereas the other part agglomerated showing the peak at 9\u00B0. The WAXD results supported a better and more homogeneous dispersion of h-MXene in S-IPN at higher nanofiller loading, as compared to the untreated MXene which corroborated with the DMA analysis. Additionally, in the WAXD pattern of the nanocomposite, no strong characteristic peaks of the rutile or anatase phase of TiO2 were observed [24].This research was supported by the Regional Leading Research Center Program (2019R1A5A8080326) through the National Research Foundation funded by the Ministry of Science and ICT of the Republic of Korea. And was supported by the Technology Innovation Program (20020872, Development of high crystalline graphitic structure-based high-efficiency and high-performance catalyst for water splitting) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).
| Funders | Funder number |
|---|---|
| Ministry of Science and ICT of Republic of Korea | |
| National Research Foundation of Korea | |
| ITECH R&D program of MOTIE | |
| Ministry of Trade, Industry and Energy | |
| Korea Evaluation Institute of Industrial Technology | 20010509 |
| Ministry of Science and ICT of the Republic of Korea | 20020872 |
Keywords
- Barrier coating
- Hydrogen storage
- Hyperbranched polyglycerol
- Interpenetrating network
- MXene