Two- dimensional Transi/on Metal Carbides Produced by Exfolia/on of MAX Phases

Transcription

1 NSF/AFOSR Workshop on 2D Materials Beyond Graphene, May 30-31, 2012 Two- dimensional Transi/on Metal Carbides Produced by Exfolia/on of MAX Phases Yury Gogotsi & Michel Barsoum Students: Michael Naguib, Olha Mashtalir, Murat Kurtoglu Drexel University AJ Drexel Nanotechnology Ins7tute Materials Science and Engineering Department Philadelphia, Pennsylvania - 1 -

2 Ternary metals carbides and/or nitrides Layered hexagonal structure (P6 3 /mmc) M Composition of X M M n+1 AX n ; with n A =1,2,3 MAX Phases Strong but Ductile Ceramics - not van der Waals Solids Examples: Ti 2 AlC, Ti 2 AlN, Ti 3 AlC 2,Ti 4 AlN 3 Ta 2 AlC, Ta 4 AlC 3 Cr 2 AlC, Cr 3 AlC 2 V 2 AlC, V 3 AlC 2 Nb 2 AlC, Nb 4 AlC 3 (>60 phases) (Ti 0.5 Nb 0.5 ) 2 AlC, Ti 3 Al(C 0.5 N 0.5 ) 2 (considering solid solution, there will be more) 2 Barsoum, M.W. Progress in Solid State Chemistry 28 (2000)

3 Schematic of Solution Synthesis Summary MAX phases are layered ternary carbides, nitrides, and carbonitrides consisjng of M, A, and X layers MAX phase SelecJve etching only of the A layers from the MAX phase MXene sheets Physically separated 2- D MXene sheets aoer sonicajon - 3 -

4 The Solution Approach to Ti 3 AlC 2 Exfoliation and Dispersion MAX MAX MXene HF Treatment Sonica/on Ti O C H Al Ti 3 AlC 2 in HF 50% for 2 hours at room temperature, then sonication Michael Naguib, et al. Advanced Materials 23 (2011)

5 XRD Analysis of MAX and MXene Ti 3 AlC 2 HF 50% for 2 hours at room temperature After HF treatment, the most intense peak of Ti 3 AlC 2 vanished. XRD after HF treatment matches with DFT simulated Ti 3 C 2 (OH) 2. Sonication results in weakening the intensity of the peaks (losing the crystalline ordering). M. Naguib, et al. Advanced Materials 23 (2011)

6 Raman Spectra of MAX and MXene (III) (VI) (V) Intensity (I) (II) Ti 3 AlC 2 (IV) HF etched Raman shift (cm -1 ) Ti 3 AlC 2 etched in 50% HF for 2 hours at room temperature Raman spectroscopy: nm excitation M. Naguib, et al. Advanced Materials 23 (2011) V. Presser, M. Naguib, et al. J. Raman Spectroscopy 43 (2011)

7 SEM Images of MXene Ti 3 AlC 2 etched in HF 50% for 2 hours at room temperature: 2 µm Exfoliated Graphite M. Naguib, et al. Advanced Materials 23 (2011) L. M. Viculis, et al., Journal of Materials Chemistry 15 (2005)

8 MXene on the Cover People s choice award for International Science & Engineering Visualization Challenge from NSF, Science 2012 Vol. 335, pp

9 TEM Analysis of Ti 3 C 2 Ti 3 AlC 2 treated in HF 50% for 2 hours at room temperature, then sonication Michael Naguib, et al. Advanced Materials 23 (2011)

10 MXene Scrolls/Nanotubes MXene shows behavior typical of graphene or other 2-D materials R<20nm 5 nm 5 nm Ti 3 AlC 2 in 50%-HF for 2 hours at room temperature, then sonication Michael Naguib, et al. Advanced Materials 23 (2011)

11 MXenes A Large Family of Transition Metal Carbides and/or Nitrides Several MAX phases have been exfoliated, producing MXenes As received Ti 3 C 2 Ti 2 C 4 µm 3 µm 2 µm Ta 4 C 3 (Ti 0.5 Nb 0.5 ) 2 C Ti 3 (C 0.5 N 0.5 ) 2 1 µm 1 µm 1 µm Michael Naguib, et al. ACS Nano 6 (2012)

12 MXenes A Large Family of Transition Metal Carbides and/or Nitrides Ti C 2 Ti 3 (C 0.5 N 0.5 ) 2 40nm 20nm (Ti 0.5 Nb 0.5 ) 2 C Ta 4 C 3 50nm 50nm Michael Naguib, et al. ACS Nano 6 (2012)

13 HR TEM and SAD of Ta 4 C 3 Crystalline structure is maintained within the layer nm 20 nm MXene layers are in registry in multilayer structures nm 60 (0110) nm (2110) 2 nm 5 1/nm M. Naguib, et al. ACS Nano 6 (2012)

14 Light Microscopy of MXenes Individual (multi)layers are optically transparent under visible light 10µm 10µm Ta 4 C 3 flakes Ti 3 CN Michael Naguib, et al. ACS Nano 6 (2012)

15 Electronic Structure of MXenes Semiconductor (0.05 ev bandgap) Ti 3 C 2 (OH) 2 : OH terminated Ti 3 C 2 nanosheets Metal Ti 3 C 2 : Bare layers, no termina/ons Semiconductor (0.1 ev bandgap) Ti 3 C 2 F 2 : F- terminated Ti 3 C 2 nanosheets DFT implemented in the CASTEP code in Material Studio software (Version 4.5) M. Naguib, et al. Advanced Materials 23 (2011)

16 Wetting and Conductivity MXene can be cold pressed in the form of thin (300 µm) freestanding discs. Resistivity is comparable to multi-layer graphene. Contact angle measurements of water showed hydrophilic behavior. 25mm Ti 2 C Ta 4 C 3 (Ti 0.5 Nb 0.5 ) 2 C Ti 3 (C 0.5 N 0.5 ) 2 R: 330 Ω/ 104 Ω/ 171 Ω/ 125 Ω/ CA: Michael Naguib, et al. ACS Nano 6 (2012)

17 Potential (V vs. Li/Li + ) MXene as a Li- ion Ba[ery Anode Number of Inserted Li in the Structure (y) nd 1 st Specific Capacity (mah g -1 ) Specific Capacity (mah g -1 ) Q discharg (C/25) Q charg (C/25) Qdischarge (C/6) Qcharge (C/6) Qdischarge (1C) Qcharge (1C/) Qdischarge (3C) Q discharg (C/25) Q charg (C/25) Qcharge (3C) Qdischarge (C/6) Qcharge (C/6) Qdischarge (10C) Qdischarge (1C) Qcharge (1C/) Data 31 Qcharge 4:08:31 PM (10C) 11/30/2011 Qdischarge (3C) Ti 2 CO x based anode properties similar to lithium titanate anodes C/25 C/ C/ C/6 1C C & 10C Cycle Number Qcharge (3C) Qdischarge (10C) Qcharge (10C) Data 31 8:36:44 PM 11/3/2011 1C 3C 10C M. Naguib, et al. Electrochemistry Communications 16 (2012)

18 Summary of the Data to Date SelecJve etching of A layer from MAX phases results in the formajon of 2- D transijon metals carbides and/or nitrides called MXenes Band gap of MXene predicted to change with the surface chemistry Excellent mechanical properjes predicted (DFT) Sufficiently ducjle for cold pressing ConducJvity comparable to mulj- layer graphene Hydrophilic (contact angle ) Li inserjon allows use in Li- ion ba[ery anodes

19 Potential Applications Electrical energy storage Pseudocapacitors, Lithium ion ba[eries, Hybrid devices Composite materials ConducJve, high- strength, low- permeability polymers, high strength and high toughness ceramic- metal composites Sensors 2- D and flexible electronics M 2 X M 4 X 3 M 3 X

20 Acknowledgments Barsoum MAX Phase Group Gogotsi Nanomaterials Group Jérémy Come & Patrice Simon, Université Paul Sabatier, Toulouse, France Jun Lu & Lars Hultman, Linkoping University, Sweden BATT Program