Nanocomposite, electrode containing the nanocomposite, and method of making the nanocomposite

Patent metadata

Field	Value
Publication number	US-2017365850-A9
Application number	US-201515111596-A
Country	US
Kind code	A9
Filing date	Jan 14, 2015
Priority date	Jan 14, 2014
Publication date	Dec 21, 2017
Grant date	—

Abstract

A nanocomposite is provided. The nanocomposite includes an electrically conductive nanostructured material; and metal fluoride nanostructures having the general formula M (I) x M (II) 1−x F 2+y−zn arranged on the electrically conductive nanostructured material, wherein M (I) and M (II) are independently transition metals, n is a stoichiometric coefficient, and wherein i) x=0, 0<y≦2, and z=0; or ii) 0<x<1, 0≦y≦2, z≧0, and M (I) and M (II) are different transition metals. An electrode including the nanocomposite and method of preparing the nanocomposite are also provided.

First claim

1 . A nanocomposite comprising
a) an electrically conductive nanostructured material; and b) metal fluoride nanostructures having the general formula M (I) x M (II) (1−x) F 2+y−zn arranged on the electrically conductive nanostructured material,
wherein M (I) and M (II) are independently transition metals, n is a stoichiometric coefficient, and wherein
i) x=0, 0<y≦2, and z=0; or
ii) 0<x<1, 0≦y≦2, z≧0, and M (I) and M (II) are different transition metals.

2 . The nanocomposite according to claim 1 , wherein M (I) and M (II) are independently selected from the group consisting of Ti, V, Fe, Ni, Co, Mn, Cr, Cu, W, Mo, Nb, and Ta.

3 . The nanocomposite according to claim 1 or 2 , wherein M (I) is Ni and M (II) is Co.

4 . The nanocomposite according to any one of claims 1 to 3 , wherein the metal fluoride nanostructures comprise or consist of CoF 3 .

5 . The nanocomposite according to any one of claims 1 to 4 , wherein the metal fluoride nanostructures comprise or consist of Ni x Co 1−x F 2 , 0<x<1.

6 . The nanocomposite according to any one of claims 1 to 5 , wherein the metal fluoride nanostructures comprise or consist of single phase metal fluoride nanostructures.

7 . The nanocomposite according to any one of claims 1 to 6 , wherein the metal fluoride nanostructures comprise an outer layer of carbon.

8 . The nanocomposite according to any one of claims 1 to 7 , wherein the metal fluoride nanostructures have a size of less than 200 nm.

9 . The nanocomposite according to any one of claims 1 to 8 , wherein the electrically conductive nanostructured material is selected from the group consisting of carbon nanotubes, carbon nanofibers, and mixtures thereof.

10 . The nanocomposite according to any one of claims 1 to 9 , wherein the metal fluoride nanostructures are arranged on an outer surface of the electrically conductive nanostructured material.

11 . An electrode comprising a nanocomposite according to any one of claims 1 to 10 .

12 . The electrode according to claim 11 , wherein amount of the electrically conductive nanostructured material in the electrode is in the range of about 20 wt % to about 45 wt %.

13 . The electrode according to claim 11 or 12 , further comprising a binder selected from the group consisting of polyvinylidene fluoride, polyacrylonitrile, poly(acrylic acid), poly(vinylidene fluoride-co-hexafluoropropylene), copolymers thereof, and mixtures thereof.

14 . The electrode according to claim 13 , wherein amount of binder in the electrode is in the range of about 10 wt % to about 20 wt %.

15 . The electrode according to any one of claims 11 to 14 , wherein the electrode is a cathode of a lithium battery.

16 . A method of preparing a nanocomposite according to any one of claims 1 to 10 , the method comprising
a) providing metal fluoride nanostructures having the general formula M (I) x M (II) (1−x) F 2+y−zn , wherein M (I) and M (II) are independently transition metals, n is a stoichiometric coefficient, and wherein
i) x=0, 0<y≦2, and z=0; or
ii) 0<x<1, 0≦y≦2, z≧0, and M (I) and M (II) are different transition metals;

and
b) arranging the metal fluoride nanostructures on an electrically conductive nanostructured material to obtain the nanocomposite.

17 . The method according to claim 16 , wherein providing the metal fluoride nanostructures comprises fluorinating a metal salt with fluorine gas and/or a fluorination agent.

18 . The method according to claim 17 , wherein fluorinating the metal salt with fluorine gas and/or a fluorination agent is carried out by thermogravimetric means in a fluorine gas environment.

19 . The method according to claim 17 or 18 , wherein fluorinating the metal salt with fluorine gas and/or a fluorination agent is carried out at a temperature in the range of about 15° C. to about 600° C.

20 . The method according to any one of claims 17 to 19 , wherein fluorinating the metal salt with fluorine gas and/or a fluorination agent is carried out for a time period of about 120 hours or less.

21 . The method according to any one of claims 17 to 20 , wherein providing the metal fluoride nanostructures further comprises chemically reducing the metal fluoride nanostructures.

22 . The method according to claim 21 , wherein chemically reducing the metal fluoride nanostructures is carried out using a reducing agent selected from the group consisting of alkali metals, alkali earth metals, lanthanides, hydrogen, hydrazine, ammonia, amines, and combinations thereof.

23 . The method according to claim 21 or 22 , wherein chemically reducing the metal fluoride nanostructures is carried out using a reducing agent selected from the group consisting of Li-naphtalenide, Na-naphtalenide, Li-biphenyl, Na-biphenyl, butyl-lithium, butyl-sodium, and combinations thereof.

24 . The method according to any one of claims 16 to 23 , wherein providing the metal fluoride nanostructures comprises
a) adding a carbon precursor to metal fluoride nanostructures to form a mixture; and
b) calcining the mixture in an inert environment to form an outer layer of carbon on the metal fluoride nanostructures.

25 . The method according to claim 24 , wherein the carbon precursor is selected from the group consisting of sucrose, oleic acid, propanol, polyethylene glycol, glucose, octane, and mixtures thereof.

26 . The method according to any one of claims 16 to 25 , wherein arranging the metal fluoride nanostructures on an electrically conductive nanostructured material comprises forming the metal fluoride nanostructures in the presence of the electrically conductive nanostructured material and depositing the metal fluoride nanostructures on the electrically conductive nanostructured material.

27 . The method according to any one of claims 16 to 26 , wherein the electrically conductive nanostructured material is selected from the group consisting of carbon nanotubes, carbon nanofibers, and mixtures thereof.

28 . The method according to claim 27 , wherein the electrically conductive nanostructured material is dispersed in a solvent to fill an interior volume of the electrically conductive nanostructured material with the solvent prior to arranging the metal fluoride nanostructures on the electrically conductive nanostructured material.

29 . The method according to claim 28 , wherein the solvent comprises or consists of a C 6 -C 10 alkane.

30 . The method according to claim 28 or 29 , wherein the solvent comprises or consists of octane.

31 . Use of a nanocomposite according to any one of claims 1 to 10 in an electrochemical cell, a symmetric supercapacitor, an asymmetric supercapacitor, a primary battery, or a rechargeable battery.

Assignees

• Univ Nanyang Tech

Inventors

• Yazami Rachid
• Teng Yin Ting

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/1397

  of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title