Ultralight conductive metallic aerogels

Patent metadata

Field	Value
Publication number	US-2020157657-A1
Application number	US-201816616260-A
Country	US
Kind code	A1
Filing date	Jun 22, 2018
Priority date	Jun 23, 2017
Publication date	May 21, 2020
Grant date	—

Abstract

In accordance with one aspect of the presently disclosed inventive concepts, a metal aerogel includes a plurality of metal nanowires formed into a porous three-dimensional structure, where pores in the structure are anisotropic.

First claim

What is claimed is:

1 . A metal aerogel, comprising:
a plurality of metal nanowires formed into a porous three-dimensional structure, wherein pores in the structure are anisotropic.

2 . The metal aerogel as recited in claim 1 , wherein the metal aerogel is essentially free of nanoparticles.

3 . The metal aerogel as recited in claim 1 , wherein the metal nanowires are silver nanowires.

4 . The metal aerogel as recited in claim 1 , wherein the metal aerogel has electrical conductivity.

5 . The metal aerogel as recited in claim 1 , wherein an electrical conductivity of the metal aerogel is at least about 35,000 siemens per meter (S/m).

6 . The metal aerogel as recited in claim 1 , wherein the pores are primarily aligned along a longitudinal axis of the three-dimensional structure.

7 . The metal aerogel as recited in claim 1 , wherein the pores are primarily aligned about perpendicular to a longitudinal axis of the three-dimensional structure.

8 . The metal aerogel as recited in claim 1 , wherein the pores of the structure have an average diameter in a range of 25 microns to about 1 micron.

9 . The metal aerogel as recited in claim 1 , wherein the pores of the structure have an average diameter in a range of about 1 micron to about 1000 microns.

10 . The metal aerogel as recited in claim 1 , wherein the metal aerogel is a metal foam.

11 . The metal aerogel as recited in claim 1 , wherein a density of the metal aerogel is at least 4.8 milligrams per cubic centimeter (mg/cc).

12 . The metal aerogel as recited in claim 1 , wherein the metal aerogel has tensile elasticity, wherein the metal aerogel has a Young's modulus up to about 16,800 pascals (Pa).

13 . The metal aerogel as recited in claim 1 , wherein the plurality of metal nanowires comprises metal nanowires formed from at least one metal selected from the group consisting of gold, silver, copper, and nickel.

14 . The metal aerogel as recited in claim 1 , wherein the plurality of metal nanowires comprises more than one type of metal nanowires.

15 . A method of forming an aerogel of metal nanowires, the method comprising:
suspending a plurality of purified metal nanowires having a polymer coating in an aqueous solution thereby creating a suspension; freeze casting the suspension; lyophilizing the frozen suspension to a dry structure of metal nanowires; and sintering the lyophilized structure of metal nanowires.

16 . The method as recited in claim 15 , wherein the purified metal nanowires are purified silver nanowires.

17 . The method of forming an aerogel of silver nanowires as recited in claim 16 , wherein the purified silver nanowires are formed by:
heating a mixture of ethylene glycol, polyvinylpyrrolidone, silver nitrite, and copper chloride; adding silver nitrite in ethylene glycol for forming silver nanowires; cooling the mixture; precipitating the silver nanowires in solvent; and rinsing the silver nanowires.

18 . The method as recited in claim 15 , wherein a concentration of the purified metal nanowires in the aqueous solution is in a range of about 2 milligrams per cubic centimeter (mg/cc) to about 50 mg/cc.

19 . The method as recited in claim 15 , comprising, after suspending the plurality of purified metal nanowires, forming a shape of the plurality of purified metal nanowires.

20 . The method as recited in claim 15 , wherein freeze casting comprises directional freeze casting using a directional temperature gradient in a first direction.

21 . The method as recited in claim 15 , wherein a temperature of the sintering is in a range of about 100 degrees Celsius to about 300 degrees Celsius.

22 . The method as recited in claim 15 , wherein a duration of sintering is in a range of about thirty minutes to about two hours.

23 . The method as recited in claim 15 , wherein the sintering is performed in an inert gas, wherein the inert gas is selected from the group consisting of: hydrogen, nitrogen, and argon.

24 . The method as recited in claim 15 , wherein the aerogel of metal nanowires is essentially free of polyvinylpyrrolidone.

Assignees

• L Livermore Nat Security Llc

Inventors

• Qian Fang
• Han Thomas
• Worsley Marcus

Classifications

• B22F2301/255

  Silver or gold · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C22C1/08 Primary

  Alloys with open or closed pores · CPC title

• H01B5/00

  Non-insulated conductors or conductive bodies characterised by their form · CPC title