Abstract
Surface terminations profoundly influence the intrinsic properties of MXenes, but existing terminations are limited to monoatomic layers or simple groups, showing disordered arrangements and inferior stability. Here we present the synthesis of MXenes with triatomic-layer borate polyanion terminations (OBO terminations) through a flux-assisted eutectic molten etching approach. During the synthesis, Lewis acidic salts act as the etching agent to obtain the MXene backbone, while borax generates BO2− species, which cap the MXene surface with an O–B–O configuration. In contrast to conventional chlorine/oxygen-terminated Nb2C with localized charge transport, OBO-terminated Nb2C features band transport described by the Drude model, exhibiting a 15-fold increase in electrical conductivity and a 10-fold improvement in charge mobility at the d.c. limit. This transition is attributed to surface ordering that effectively mitigates charge carrier backscattering and trapping. Additionally, OBO terminations provide Ti3C2 MXene with substantially enriched Li+-hosting sites and thereby a large charge-storage capacity of 420 mAh g−1. Our findings illustrate the potential of intricate termination configurations in MXenes and their applications for (opto)electronics and energy storage.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
Data availability
All data are available in the main text or the Supplementary Information. Source data are provided with this paper.
References
Anasori, B., Lukatskaya, M. R. & Gogotsi, Y. 2D metal carbides and nitrides (MXenes) for energy storage. Nat. Rev. Mater. 2, 16098 (2017).
Zhao, T. et al. Ultrathin MXene assemblies approach the intrinsic absorption limit in the 0.5–10 THz band. Nat. Photonics 17, 622–628 (2023).
Zheng, W. et al. Band transport by large Fröhlich polarons in MXenes. Nat. Phys. 18, 544–550 (2022).
Liu, S. et al. Hydrogen storage in incompletely etched multilayer Ti2CTx at room temperature. Nat. Nanotechnol. 16, 331–336 (2021).
Xie, X. et al. Microstructure and surface control of MXene films for water purification. Nat. Sustain. 2, 856–862 (2019).
Mohammadi, A. V., Rosen, J. & Gogotsi, Y. The world of two-dimensional carbides and nitrides (MXenes). Science 372, eabf1581 (2021).
Faraji, M. et al. Surface modification of titanium carbide MXene monolayers (Ti2C and Ti3C2) via chalcogenide and halogenide atoms. Phys. Chem. Chem. Phys. 23, 15319–15328 (2021).
Hart, J. L. et al. Control of MXenes’ electronic properties through termination and intercalation. Nat. Commun. 10, 522 (2019).
Kamysbayev, V. et al. Covalent surface modifications and superconductivity of two-dimensional metal carbide MXenes. Science 369, 979–983 (2020).
Li, Y. et al. A general Lewis acidic etching route for preparing MXenes with enhanced electrochemical performance in non-aqueous electrolyte. Nat. Mater. 19, 894–899 (2020).
Li, M. et al. Halogenated Ti3C2 MXenes with electrochemically active terminals for high-performance zinc ion batteries. ACS Nano 15, 1077–1085 (2021).
Li, M. et al. Element replacement approach by reaction with Lewis acidic molten salts to synthesize nanolaminated MAX phases and MXenes. J. Am. Chem. Soc. 141, 4730–4737 (2019).
Ding, H. et al. Chemical scissor-mediated structural editing of layered transition metal carbides. Science 379, 1130–1135 (2023).
Wang, C. et al. HCl-based hydrothermal etching strategy toward fluoride-free MXenes. Adv. Mater. 33, 2101015 (2021).
Li, T. et al. Fluorine-free synthesis of high-purity Ti3C2Tx (T=OH, O) via alkali treatment. Angew. Chemie Int. Ed. 57, 6115–6119 (2018).
Yang, S. et al. Fluoride-free synthesis of two-dimensional titanium carbide (MXene) using a binary aqueous system. Angew. Chem. Int. Ed. 57, 15491–15495 (2018).
Shi, H. et al. Ambient-stable two-dimensional titanium carbide (MXene) enabled by iodine etching. Angew. Chem. Int. Ed. 60, 8689–8693 (2021).
Lai, S. et al. Surface group modification and carrier transport properties of layered transition metal carbides (Ti2CTx, T: –OH, –F and –O). Nanoscale 7, 19390–19396 (2015).
Saha, A. et al. Enhancing the energy storage capabilities of Ti3C2Tx MXene electrodes by atomic surface reduction. Adv. Funct. Mater. 31, 2106294 (2021).
Zhou, B., Sun, Z., Yao, Y. & Pan, Y. Correlations between 11B NMR parameters and structural characters in borate and borosilicate minerals investigated by high-resolution MAS NMR and ab initio calculations. Phys. Chem. Miner. 39, 363–372 (2012).
Ravel, B. & Newville, M. ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J. Synchrotron Radiat. 12, 537–541 (2005).
Michałowski, P. P. et al. Oxycarbide MXenes and MAX phases identification using monoatomic layer-by-layer analysis with ultralow-energy secondary-ion mass spectrometry. Nat. Nanotechnol. 17, 1192–1197 (2022).
Toby, B. H. & Von Dreele, R. B. GSAS-II: the genesis of a modern open-source all purpose crystallography software package. J. Appl. Crystallogr. 46, 544–549 (2013).
Halim, J. et al. Variable range hopping and thermally activated transport in molybdenum-based MXenes. Phys. Rev. B 98, 104202 (2018).
Němec, H., Ǩuel, P. & Sundström, V. Charge transport in nanostructured materials for solar energy conversion studied by time-resolved terahertz spectroscopy. J. Photochem. Photobiol. A 215, 123–139 (2010).
Ulbricht, R., Hendry, E., Shan, J., Heinz, T. F. & Bonn, M. Carrier dynamics in semiconductors studied with time-resolved terahertz spectroscopy. Rev. Mod. Phys. 83, 543–586 (2011).
Dong, R. et al. High-mobility band-like charge transport in a semiconducting two-dimensional metal–organic framework. Nat. Mater. 17, 1027–1032 (2018).
Cocker, T. L. et al. Microscopic origin of the Drude–Smith model. Phys. Rev. B 96, 205439 (2017).
Zheng, W., Bonn, M. & Wang, H. I. Photoconductivity multiplication in semiconducting few-layer MoTe2. Nano Lett. 20, 5807–5813 (2020).
Wang, X. et al. Influences from solvents on charge storage in titanium carbide MXenes. Nat. Energy 4, 241–248 (2019).
Wang, D. et al. Direct synthesis and chemical vapor deposition of 2D carbide and nitride MXenes. Science 379, 1242–1247 (2023).
Zhou, C. et al. Hybrid organic–inorganic two-dimensional metal carbide MXenes with amido- and imido-terminated surfaces. Nat. Chem. 15, 1722–1729 (2023).
Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).
Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).
Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).
Grimme, S. Semiempirical GGA‐type density functional constructed with a long‐range dispersion correction. J. Comput. Chem. 27, 1787–1799 (2006).
Limas, N. G. & Manz, T. A. Introducing DDEC6 atomic population analysis: part 4. Efficient parallel computation of net atomic charges, atomic spin moments, bond orders, and more. RSC Adv. 8, 2678–2707 (2018).
Henkelman, G. & Jónsson, H. Improved tangent estimate in the nudged elastic band method for finding minimum energy paths and saddle points. J. Chem. Phys. 113, 9978–9985 (2000).
Henkelman, G., Uberuaga, B. P. & Jónsson, H. A climbing image nudged elastic band method for finding saddle points and minimum energy paths. J. Chem. Phys. 113, 9901–9904 (2000).
Acknowledgements
We acknowledge support from European Union’s Horizon 2020 Research and Innovation programme (GrapheneCore3 881603, LIGHT-CAP 101017821, GREENCAP 101091572, X.F.), M-ERA.NET and Sächsisches Staatsministerium für Wissenschaft und Kunst (HYSUCAP 100478697, E.Z., T.Š., X.F.), and the German Research Foundation (DFG, CRC1415, grant number 417590517, E.B., M.Y., X.F.). TAČR EPSILON project (number TH71020004, T.Š.), GAČR project (number 23-07617 S, T.Š.) and CzechNanoLab project (number LM2023051, T.Š.) funded by MEYS CR are gratefully acknowledged for the financial support of the measurements in the CEITEC Nano Research Infrastructure. D.B. acknowledges support of computational resources in Mons by the FNRS ‘Consortium des Equipements de Calcul Intensif−CECI’ programme (grant number 2.5020.11) and by the Walloon Region (ZENOBE Tier-1 supercomputer, 1117545). D.L. acknowledges support from the China Scholarships Council (CSC). P.P.M. was supported by the National Science Centre (project number 2018/31/D/ST5/00399) and the National Centre for Research and Development (project number LIDER/8/0055/L-12/20/NCBR/2021). The authors acknowledge the use of the facilities at the Dresden Center for Nanoanalysis (DCN), Technische Universität Dresden, the Gemeinsamen Wissenschaftskonferenz (GWK) support for providing computing time through the Center for Information Services and High-Performance Computing (ZIH) at TU Dresden, and beam-time allocation at beamline P65 of the PETRA III synchrotron (DESY, Hamburg, Germany) and beamline BL04 of the ALBA synchrotron (Barcelona, Spain). We specially thank S. Voborný, P. Jadhao and P. Chen for helpful discussions.
Author information
Authors and Affiliations
Contributions
M.Y. and X.F. conceived and supervised the research. D.L. performed most of the experiments and analysis. W.Z., H.I.W. and M.B. performed the THz spectra test and analysis. S.M.G. and D.B. implemented the theoretical calculations. K.S., M.H., M.D., E.Z. and T.Š. conducted the transmission electron microscopy test and analysis. J.P. performed the XPS test. P.P.M. carried out the SIMS test. N.L. and E.B. conducted the solid-state NMR test. Z.L. and S.Z. carried out the electrical conductivity test. J.Z. assisted with XAS experiment. D.S. assisted with electrochemical experiments. D.L. prepared the paper under the supervision of M.Y. and X.F. All the authors read and revised the paper.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature Materials thanks Michel Barsoum, Qing Huang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Supplementary Information
Supplementary Figs. 1–41 and Tables 1–9.
Source data
Source Data Fig. 2
Analysed data used to plot Fig. 2b–h.
Source Data Fig. 3
Analysed data used to plot Fig. 3e–h.
Source Data Fig. 4
Analysed data used to plot Fig. 4a–f.
Source Data Fig. 5
Analysed data used to plot Fig. 5a,b,d–f.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Li, D., Zheng, W., Gali, S.M. et al. MXenes with ordered triatomic-layer borate polyanion terminations. Nat. Mater. (2024). https://doi.org/10.1038/s41563-024-01911-2
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41563-024-01911-2
