Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Conductive two-dimensional titanium carbide ‘clay’ with high volumetric capacitance

Abstract

Safe and powerful energy storage devices are becoming increasingly important. Charging times of seconds to minutes, with power densities exceeding those of batteries, can in principle be provided by electrochemical capacitors—in particular, pseudocapacitors1,2. Recent research has focused mainly on improving the gravimetric performance of the electrodes of such systems, but for portable electronics and vehicles volume is at a premium3. The best volumetric capacitances of carbon-based electrodes are around 300 farads per cubic centimetre4,5; hydrated ruthenium oxide can reach capacitances of 1,000 to 1,500 farads per cubic centimetre with great cyclability, but only in thin films6. Recently, electrodes made of two-dimensional titanium carbide (Ti3C2, a member of the ‘MXene’ family), produced by etching aluminium from titanium aluminium carbide (Ti3AlC2, a ‘MAX’ phase) in concentrated hydrofluoric acid, have been shown to have volumetric capacitances of over 300 farads per cubic centimetre7,8. Here we report a method of producing this material using a solution of lithium fluoride and hydrochloric acid. The resulting hydrophilic material swells in volume when hydrated, and can be shaped like clay and dried into a highly conductive solid or rolled into films tens of micrometres thick. Additive-free films of this titanium carbide ‘clay’ have volumetric capacitances of up to 900 farads per cubic centimetre, with excellent cyclability and rate performances. This capacitance is almost twice that of our previous report8, and our synthetic method also offers a much faster route to film production as well as the avoidance of handling hazardous concentrated hydrofluoric acid.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Schematic of MXene clay synthesis and electrode preparation.
Figure 2: Structural characterization of MXene.
Figure 3: Electrochemical performance of rolled, free-standing electrodes.

Similar content being viewed by others

References

  1. Simon, P. & Gogotsi, Y. Materials for electrochemical capacitors. Nature Mater. 7, 845–854 (2008)

    Article  CAS  ADS  Google Scholar 

  2. Augustyn, V. et al. High-rate electrochemical energy storage through Li+ intercalation pseudocapacitance. Nature Mater. 12, 518–522 (2013)

    Article  CAS  ADS  Google Scholar 

  3. Gogotsi, Y. & Simon, P. True performance metrics in electrochemical energy storage. Science 334, 917–918 (2011)

    Article  CAS  ADS  Google Scholar 

  4. Murali, S. et al. Volumetric capacitance of compressed activated microwave-expanded graphite oxide (a-MEGO) electrodes. Nano Energy 2, 764–768 (2013)

    Article  CAS  Google Scholar 

  5. Yang, X., Cheng, C., Wang, Y., Qiu, L. & Li, D. Liquid-mediated dense integration of graphene materials for compact capacitive energy storage. Science 341, 534–537 (2013)

    Article  CAS  ADS  Google Scholar 

  6. Zheng, J. P., Cygan, P. J. & Jow, T. R. Hydrous ruthenium oxide as an electrode material for electrochemical capacitors. J. Electrochem. Soc. 142, 2699–2703 (1995)

    Article  CAS  Google Scholar 

  7. Naguib, M. et al. Two-dimensional nanocrystals produced by exfoliation of Ti3AlC2 . Adv. Mater. 23, 4248–4253 (2011)

    Article  CAS  Google Scholar 

  8. Lukatskaya, M. R. et al. Cation intercalation and high volumetric capacitance of two-dimensional titanium carbide. Science 341, 1502–1505 (2013)

    Article  CAS  ADS  Google Scholar 

  9. Nicolosi, V., Chhowalla, M., Kanatzidis, M. G., Strano, M. S. & Coleman, J. N. Liquid exfoliation of layered materials. Science 340, 6139 (2013)

    Article  Google Scholar 

  10. Ghaffari, M. et al. High-volumetric performance aligned nano-porous microwave exfoliated graphite oxide-based electrochemical capacitors. Adv. Mater. 25, 4879–4885 (2013)

    Article  CAS  Google Scholar 

  11. Tao, Y. et al. Towards ultrahigh volumetric capacitance: graphene derived highly dense but porous carbons for supercapacitors. Sci. Rep. 3, 2975 (2013)

    Article  Google Scholar 

  12. Jung, I., Dikin, D. A., Piner, R. D. & Ruoff, R. S. Tunable electrical conductivity of individual graphene oxide sheets reduced at “low” temperatures. Nano Lett. 8, 4283–4287 (2008)

    Article  CAS  ADS  Google Scholar 

  13. Barsoum, M. W. MAX Phases: Properties of Machinable Ternary Carbides and Nitrides (John Wiley & Sons, 2013)

    Book  Google Scholar 

  14. Naguib, M., Mochalin, V. N., Barsoum, M. W. & Gogotsi, Y. MXenes: a new family of two-dimensional materials. Adv. Mater. 26, 982 (2014)

    Article  Google Scholar 

  15. Xie, X. et al. Surface Al leached Ti3AlC2 substituting carbon for catalyst support served in a harsh corrosive electrochemical system. Nanoscale 6, 11035–11040 (2014)

    Article  CAS  ADS  Google Scholar 

  16. Peng, Q. et al. Unique lead adsorption behavior of activated hydroxyl group in two-dimensional titanium carbide. J. Am. Chem. Soc. 136, 4113–4116 (2014)

    Article  CAS  Google Scholar 

  17. Tang, Q., Zhou, Z. & Shen, P. Are MXenes promising anode materials for Li ion batteries? computational studies on electronic properties and Li storage capability of Ti3C2 and Ti3C2X2 (X = F, OH) monolayer. J. Am. Chem. Soc. 134, 16909–16916 (2012)

    Article  CAS  Google Scholar 

  18. Mashtalir, O. et al. Intercalation and delamination of layered carbides and carbonitrides. Nature Commun. 4, 1716 (2013)

    Article  ADS  Google Scholar 

  19. Halim, J. et al. Transparent conductive two-dimensional titanium carbide epitaxial thin films. Chem. Mater. 26, 2374–2381 (2014)

    Article  CAS  Google Scholar 

  20. Chang, F., Li, C., Yang, J., Tang, H. & Xue, M. Synthesis of a new graphene-like transition metal carbide by de-intercalating Ti3AlC2 . Mater. Lett. 109, 295–298 (2013)

    Article  CAS  Google Scholar 

  21. Enyashin, A. N. & Ivanovskii, A. L. Two-dimensional titanium carbonitrides and their hydroxylated derivatives: structural, electronic properties and stability of MXenes Ti3C2−xNx(OH)2 from DFTB calculations. J. Solid State Chem. 207, 42–48 (2013)

    Article  CAS  ADS  Google Scholar 

  22. Madsen, F. T. & Müller-Vonmoos, M. The swelling behaviour of clays. Appl. Clay Sci. 4, 143–156 (1989)

    Article  CAS  Google Scholar 

  23. Hensen, E. J. & Smit, B. Why clays swell. J. Phys. Chem. B 106, 12664–12667 (2002)

    Article  CAS  Google Scholar 

  24. Lis, D., Backus, E. H. G., Hunger, J., Parekh, S. H. & Bonn, M. Liquid flow along a solid surface reversibly alters interfacial chemistry. Science 344, 1138–1142 (2014)

    Article  CAS  ADS  Google Scholar 

  25. Mashtalir, O., Naguib, M., Dyatkin, B., Gogotsi, Y. & Barsoum, M. W. Kinetics of aluminum extraction from Ti3AlC2 in hydrofluoric acid. Mater. Chem. Phys. 139, 147–152 (2013)

    Article  CAS  Google Scholar 

  26. Conway, B. Electrochemical capacitors based on pseudocapacitance. In Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications (Kluwer Academic/Plenum, 1999)

    Chapter  Google Scholar 

  27. Dmowski, W., Egami, T., Swider-Lyons, K. E., Love, C. T. & Rolison, D. R. Local atomic structure and conduction mechanism of nanocrystalline hydrous RuO2 from X-ray scattering. J. Phys. Chem. B 106, 12677–12683 (2002)

    Article  CAS  Google Scholar 

  28. Wang, J., Polleux, J., Lim, J. & Dunn, B. Pseudocapacitive contributions to electrochemical energy storage in TiO2 (anatase) nanoparticles. J. Phys. Chem. C 111, 14925–14931 (2007)

    Article  CAS  Google Scholar 

  29. Levi, M. D. et al. Solving the capacitive paradox of 2D MXene by electrochemical quartz-crystal admittance and in situ electronic conductance measurements. Adv. Energy Mater. http://dx.doi.org/10.1002/aenm.201400815 (2014)

  30. Simon, P., Gogotsi, Y. & Dunn, B. Where do batteries end and supercapacitors begin? Science 343, 1210–1211 (2014)

    Article  CAS  ADS  Google Scholar 

Download references

Acknowledgements

We thank O. Mashtalir and Z. Ling for help with material characterization. This work was supported by the US National Science Foundation under grant number DMR-1310245. Electrochemical research was supported by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, and Office of Basic Energy Sciences. XRD, X-ray photoelectron spectroscopy, SEM and TEM investigations were performed at the Centralized Research Facilities at Drexel University.

Author information

Authors and Affiliations

Authors

Contributions

M.G. conducted material synthesis and XRD analysis. M.R.L. performed electrochemical measurements and SEM analysis. M.-Q.Z. performed TEM analysis. M.W.B. and Y.G. planned and supervised the research. M.R.L., M.G., M.W.B. and Y.G. wrote the manuscript.

Corresponding authors

Correspondence to Yury Gogotsi or Michel W. Barsoum.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Processing of MXene clay.

a, Dried and crushed powder. b, c, Hydrated clay is plastic and can be readily formed and moulded. d, Demonstration of films produced in the roller mill. e, f, Rolled freestanding film being lifted off Celgard membranes.

Extended Data Figure 2 SEM images.

a, Multilayer MXene particle. b, Cross-section of rolled Ti3C2 film, showing shearing that is most probably responsible for the loss of the 60° angle peak in the XRD pattern.

Extended Data Figure 3 Contact angle.

Digital image showing contact angle of a water droplet on rolled MXene film, indicating its hydrophilic surface.

Extended Data Figure 4 TEM characterization of dispersed Ti3C2Tx flakes.

a, Representative TEM image showing the morphology and size of a large single-layer Ti3C2Tx flake. Note folding on all sides of this large flake. b, The lateral size distribution of the dispersed Ti3C2Tx flakes. ce, Representative TEM images showing single-layer (c), double-layer (d) and triple-layer (e) flakes. f, Statistical analysis of layer number distribution of dispersed Ti3C2Tx flakes. Note that the fractions of double- and few-layer flakes are overestimated owing to inevitable restacking and edge folding of single-layer flakes during preparation of samples for TEM analysis. Edge folding is clearly seen in a. An example of restacking is shown in Extended Data Fig. 5.

Extended Data Figure 5 TEM image showing the restacking of single- or double-layer MXene flakes into few-layer MXene.

Extended Data Figure 6 Gravimetrically normalized capacitance.

Cyclic voltammetry profiles at different scan rates for 5-µm-thick (a), 30-µm-thick (b) and 75-µm-thick (c) electrodes in 1 M H2SO4. d, Gravimetric rate performances of rolled electrodes, 5 µm thick (black squares), 30 µm thick (red circles) and 75 µm thick (blue triangles).

Extended Data Table 1 Effect of film thickness and scan rate on mass- and volume-normalized capacitance values

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ghidiu, M., Lukatskaya, M., Zhao, MQ. et al. Conductive two-dimensional titanium carbide ‘clay’ with high volumetric capacitance. Nature 516, 78–81 (2014). https://doi.org/10.1038/nature13970

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature13970

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing