Electrochemical systems comprising MXenes and MAX phase compositions and methods of using the same
Disclosed herein are electrochemical cells comprising electrodes prepared from layered materials comprising a substantially two-dimensional ordered array of cells having an empirical formula of M n+1 X n , where M comprises a transition metal selected from the group consisting of a Group IIIB metal, a Group IVB metal, a Group VB metal, a Group VIB metal, and any combination thereof, X is C x N y wherein x+y=n, and n is equal to 1, 2, or 3. Also disclosed herein are batteries comprising the electrochemical cells and methods for electrochemically preparing MXene compositions with the use of the electrochemical cells.
1. A method of preparing an MXene composition comprising providing an electrochemical cell and applying a potential to the electrochemical cell for an effective amount of time to electrochemically etch a MAX phase composition to remove substantially all of an A-group element,
wherein the electrochemical cell comprises:
(a) an electrode comprising a layered material having a plurality of layers, each of the layers comprising a substantially two-dimensional ordered array of cells,
wherein the layered material comprises the MAX phase composition having an empirical formula of M n+1 AX n ,
wherein A comprises the A-group element and the A-group element is selected from the group consisting of Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Tl, Pb, and any combination thereof,
wherein M comprises a transition metal selected from the group consisting of a Group IIIB metal, a Group IVB metal, a Group VB metal, a Group VIB metal, and any combination thereof;
wherein X is C x N y wherein x+y=n; and
wherein n is equal to 1, 2, or 3; and
(b) an electrolyte,
wherein the electrode is a working electrode and the electrochemical cell further comprises a counter electrode and/or a reference electrode.
2. The method of claim 1 , wherein the A-group element comprises Al.
3. The method of claim 1 , wherein the electrolyte comprises a room-temperature ionic liquid or a deep eutectic solvent.
4. The method of claim 1 , wherein the potential is an anodic potential.
5. The method of claim 1 , wherein electrochemically etching the MAX phase composition comprises applying the potential to the electrochemical cell for an effective amount of time to prepare a MXene composition have an empirical formula of M n+1 A y X n,
wherein y is less than 0.5.
6. The method of claim 5 , wherein y is less than 0.2.
7. The method of claim 5 , wherein the potential is an anodic potential.
8. The method of claim 2 , wherein the MAX phase composition comprises a composition having an empirical formula selected from the group consisting of Ti 2 AlC, V 2 AlC, Cr 2 AlC, Nb 2 AlC, Ta 2 AlC, Ti 3 AlC 2 , V 3 AlC 2 , Ta 3 AlC 2 , Ti 4 AlC 3 , V 4 AlC 3 , Nb 4 AlC 3 , Ta 4 AlC 3 , Mo 2 TiAlC 2 , Cr 2 TiAlC 2 , Mo 2 Ti 2 AlC 3 , and any combination thereof.
9. The method of claim 8 , wherein the method prepares an MXene composition having an empirical formula selected from the group consisting of Ti 2 Al y C, V 2 Al y C, Cr 2 Al y C, Nb 2 Al y C, Ta 2 Al y C, Ti 3 Al y C2, V 3 Al y C2, Ta 3 Al y C 2 , Ti 4 Al y C 3 , 5 V 4 Al y C 3 , Nb 4 Al y C 3 , Ta 4 Al y C 3 , Mo 2 TiAl y C 2 , Cr 2 TiAl y C 2 , Mo 2 Ti 2 AlyC 3 , and any combination thereof.
10. The method of claim 3 , wherein the electrolyte comprises [AlX 4 ] − , [Al 2 X 7 ] − , or any combination thereof and each X is independently selected from Cl or Br.
11. The method of claim 10 , wherein X is Cl.
12. The method of claims 10 , wherein the electrolyte further comprises a cation comprising a member of the group consisting of a imidazolium cation, a pyridinium cation, an ammonium cation, a piperidinium cation, a pyrrolidinium cation, an alkali cation, an any combination thereof or wherein the electrolyte further comprises a polar molecule selected from the group consisting of urea, dimethylsulfone, an amide, a glyme, or a combination thereof.
13. The method of claim 3 , wherein the electrolyte comprises the room-temperature ionic liquid.
14. The method of claim 13 , wherein the electrolyte comprises [AlX 4 ] − , [Al 2 X 7 ] − , or any combination thereof and each X is independently selected from Cl or Br.
15. The method of claim 14 , wherein the electrolyte further comprises a cation comprising a member of the group consisting of a imidazolium cation, a pyridinium cation, an ammonium cation, a piperidinium cation, a pyrrolidinium cation, an alkali cation, and any combination thereof.
16. The method of claim 3 , wherein the electrolyte comprises the deep eutectic solvent.
17. The method of claim 16 , wherein the electrolyte comprises [AlX 4 ] − , [Al 2 X 7 ] − , or any combination thereof and each X is independently selected from Cl or Br.
18. The method of claims 17 , wherein the electrolyte further comprises a polar molecule selected from the group consisting of urea, dimethylsulfone, an amide, a glyme, or a combination thereof.