Abstract
One of the primary factors limiting further research and commercial use of the two-dimensional (2D) titanium carbide MXene Ti3C2, as well as MXenes in general, is the rate at which freshly made samples oxidize and degrade when stored as aqueous suspensions. Here, we show that including excess aluminum during synthesis of the Ti3AlC2 MAX phase precursor leads to Ti3AlC2 grains with improved crystallinity and carbon stoichiometry (termed Al-Ti3AlC2). MXene nanosheets (Al-Ti3C2) produced from this precursor are of higher quality, as evidenced by their increased resistance to oxidation and an increase in their electronic conductivity up to 20 »000 S/cm. Aqueous suspensions of stoichiometric single- to few-layer Al-Ti3C2 flakes produced from the modified Al-Ti3AlC2 have a shelf life of over ten months, compared to 1 to 2 weeks for previously published Ti3C2, even when stored in ambient conditions. Freestanding films made from Al-Ti3C2 suspensions stored for ten months show minimal decreases in electrical conductivity and negligible oxidation. Furthermore, oxidation of the improved Al-Ti3C2 in air initiates at temperatures that are 100-150 °C higher than that of conventional Ti3C2. The observed improvements in both the shelf life and properties of Al-Ti3C2 will facilitate the widespread use of this material.
| Original language | English |
|---|---|
| Pages (from-to) | 6420-6429 |
| Number of pages | 10 |
| Journal | ACS Nano |
| Volume | 15 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 27 2021 |
| Externally published | Yes |
Funding
The synthesis and characterization of MAX and MXene materials performed in this study was supported by the Fluid Interface Reactions, Structures & Transport (FIRST) Center, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. M.A. was supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1646737. A.C.F. and E.A.S. acknowledge the Vagelos Institute for Energy Science and Technology at the University of Pennsylvania for a graduate fellowship. This work was performed in part at the Singh Center for Nanotechnology at the University of Pennsylvania, a member of the National Nanotechnology Coordinated Infrastructure (NNCI) network, which is supported by the National Science Foundation (Grant No. NNCI-1542153). Additional support for the electron microscopy facilities was provided by the supported by NSF through the University of Pennsylvania Materials Research Science and Engineering Center (MRSEC) (DMR-1720530). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. SEM, XRD, XPS, and TEM analysis were performed using instruments in the Materials Characterization Core at Drexel University. This manuscript was previously submitted to the preprint server ChemRxiv on August 14th, 2020. The preprint version can be found under the following: Mathis, Tyler; Maleski, Kathleen; Goad, Adam; Sarycheva, Asia; Anayee, Mark; Foucher, Alexandre C.; Hantanasirisakul, Kanit; Stach, Eric A.; Gogotsi, Yury. (2020): Modified MAX Phase Synthesis for Environmentally Stable and Highly Conductive Ti C MXene. ChemRxiv. Preprint. 10.26434/chemrxiv.12805280.v1 3 2
| Funders | Funder number |
|---|---|
| University of Pennsylvania Materials Research Science and Engineering Center | |
| Vagelos Institute for Energy Science and Technology | |
| National Science Foundation | DGE-1646737 |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | |
| University of Pennsylvania | NNCI-1542153 |
| Materials Research Science and Engineering Center, Harvard University | DMR-1720530 |
Keywords
- electronic conductivity
- long-term stability
- MXene
- oxidation resistance
- TiC