Porous electrolyte membrane, manufacturing process thereof and electrochemical devices comprising same

Patent metadata

Field	Value
Publication number	US-2018115014-A1
Application number	US-201615560516-A
Country	US
Kind code	A1
Filing date	Mar 25, 2016
Priority date	Mar 26, 2015
Publication date	Apr 26, 2018
Grant date	—

Abstract

A porous electrolyte membrane including a first main surface and a second main surface that are separated by a thickness, where carbon nanotubes, defining through-pores or through-channels that are open at their two ends, have a diameter smaller than or equal to 100 nm, are oriented in the direction of the thickness of the membrane, and are all substantially parallel over the entire thickness of the membrane, connect the first main surface and the second main surface; the carbon nanotubes are separated by a space, and the space between the carbon nanotubes is completely filled with at least one solid material, and an electrolyte is confined inside the carbon nanotubes. A method for preparing the membrane and an electrochemical device, such as a lithium accumulator or battery, including the electrolyte membrane.

First claim

1 . A porous membrane comprising an electrolyte, comprising a first main surface and a second main surface separated by a thickness wherein:
carbon nanotubes, defining through-pores or through-channels open at both of their ends, with a diameter of less than or equal to 100 nm, oriented in the direction of the thickness of the membrane and all substantially parallel, on the totality of the thickness of the membrane, connect the first main surface and the second main surface; the carbon nanotubes are separated by a space, and said space between the carbon nanotubes is totally filled with at least one solid material; an electrolyte is confined inside the carbon nanotubes; and the chemical composition of the confined electrolyte is the same in all the inside of the carbon nanotubes.

2 . The membrane according to claim 1 , wherein the first and the second main surfaces are planar and parallel, the membrane is a planar membrane and the nanotubes, the pores or channels, are substantially aligned, or aligned, perpendicularly to said surface.

3 . The membrane according to claim 1 , wherein the carbon nanotubes are functionalized on their outer wall in order to make them electronically insulating, by fluorination, or by an organic compound which makes them electronically insulating; or else the carbon nanotubes are functionalized, on their outer wall with redox species and/or electroactive species.

4 . The membrane according to claim 1 , wherein the nanotubes have an internal diameter from 1 to 100 nm.

5 . The membrane according to claim 1 , wherein the carbon nanotubes and the pores or channels have a length, from 10 microns to 100 mm.

6 . The membrane according to claim 1 , wherein the solid material is selected from the group consisting of electronically insulating materials and electronically conducting materials for which the outer surface, in contact with the outside of the membrane, has been made electronically insulating.

7 . The membrane according to claim 1 , wherein the solid material is selected from the group consisting of organic polymers, metals and metal oxides.

8 . The membrane according to claim 1 , wherein the electrolyte is at least one selected from the group consisting of a proton carrier, a proton conductor a protonic conducting polymer, a zwitterion ionic liquid, an acid dissolved in an organic polymer, an ionic liquid, an ionic liquid comprising an ionic conducting salt, a liquid organic solvent or an organic polymer comprising an ionic conducting salt, an ionic liquid in an organic polymer, a mixture of an organic polymer and of an organic solvent, a mixture of an ionic liquid and of an organic solvent, a mixture of an ionic liquid, of an organic solvent and of a salt of an alkaline or earth-alkaline metal, a mixture of an organic polymer, of an organic solvent and of a salt of an alkaline or earth-alkaline metal, and a mixture of a salt of an alkaline or earth-alkaline metal.

9 . The membrane according to claim 8 , wherein the organic polymer is a polymer selected from the group consisting of homopolymers and copolymers of ethylene oxide, and their derivatives.

10 . The membrane according to claim 8 , wherein the organic polymer has a molar mass of less than 10 6 g/mol.

11 . The membrane according to claim 8 , wherein the ionic conducting salt is a salt of an alkaline metal or a salt of an earth-alkaline metal.

12 . The membrane according to claim 11 , wherein the ionic conducting salt is a lithium salt, selected from the group consisting of LiAsF 6 , LiClO 4 , LiBF 4 , LiPF 6 , lithium bis(oxalato)borate (LiBOB), LiODBF, LiB(C 6 H 5 ), LiR F SO 3 , LiCH 3 SO 3 , LiN(R F SO 2 ) 2 , LiC(R F SO 2 ) 3 , wherein R F is selected from the group consisting of a fluorine atom and a perfluoroalkyl group comprising from 1 to 9 carbon atoms, or a sodium salt analogous to the lithium salts thereof but comprising a sodium ion instead of a lithium ion.

13 . The membrane according to claim 8 , wherein the concentration of ionic conducting salt, in the electrolyte is from 1 to 50% by mass based on the mass of the electrolyte.

14 . The membrane according to claim 1 , wherein the electrolyte totally fills the carbon nanotubes.

15 . A method for preparing the porous membrane with an electrolyte according to claim 1 , wherein the following successive a) and b) are carried out:
a) growing carbon nanotubes, all substantially parallel, and separated by a space, on a surface of a substrate provided with a growth catalyst of carbon nanotubes; b) totally filling said space between the carbon nanotubes with a solid material; or else the following a1) is carried out: a1) growing carbon nanotubes, all substantially parallel, and separated, on a surface of a substrate and inside the pores of a porous solid material with oriented pores; and then, at the end of b) or of a1), the following c) is carried out: c) removing the substrate and, any possible solid material in excess, and opening both ends of the carbon nanotubes; and then, at the end of c), the following d) is carried out: d) filling the inside of the nanotubes with an electrolyte.

16 . The method according to claim 15 , wherein the growth substrate is a silicon wafer, or a stainless steel or aluminium sheet on which is deposited an alumina layer, and the growth catalyst of the carbon nanotubes is deposited on the alumina layer.

17 . The method according to claim 15 , wherein the growth catalyst of the carbon nanotubes is selected from the group consisting of iron, nickel, cobalt, and alloys thereof.

18 . The method according to claim 15 , wherein the carbon nanotubes are grown by a chemical vapor deposition method CVD.

19 . The method according to claim 15 , wherein the solid material is an organic polymer and b) is carried out:
either by dissolving the organic polymer in a solvent in order to form a solution of the organic polymer, by totally filling the space between the carbon nanotubes with the solution of the organic polymer and by evaporating the solvent; or by heating the organic polymer in the absence of any solvent above its glass transition temperature (Tg) or above its melting point for making it fluid, and by leaving the fluid polymer be absorbed in the space between the carbon nanotubes; or by filling the space between the carbon nanotubes with a mixture comprising organic monomers, or organic oligomers modified by reactive functions, or organic copolymers, and further one or several photosensitive and/or thermo-sensitive free radicals initiator(s); and then by cross-linking the mixture thermally or by means of photon radiation.

20 . The method according to claim 15 , wherein the solid material is a metal, and then b) is carried out by depositing said metal by an electrochemical deposition method in the space between the carbon nanotubes, or else the solid material is a metal oxide and then b) is carried out by depositing said metal oxide by an electrochemical deposition method, or by a sol-gel method, in the space between the carbon nanotubes.

21 . The method according to claim 15 , wherein b) is carried out by projecting said solid material in the space between the carbon nanotubes.

22 . The method according to claim 15 , wherein c) is carried out by mechanical polishing and/or plasma etching.

23 . An electrochemical device comprising a membrane comprising an electrolyte according to claim 1 .

24 . A lithium accumulator, or battery,

Assignees

• Commissariat Energie Atomique
• Centre Nat Rech Scient
• Commissariat A Lenergie Atomique Et Aux Alternatives
• Centre National De La Rech Scientfique

Inventors

• Zanotti Jean-Marc
• Berrod Quentin
• Dijon Jean
• Ferdeghini Filippo
• Judeinstein Patrick

Classifications

• B01D69/148

  Organic/inorganic mixed matrix membranes · CPC title

• H01M2300/0065

  Solid electrolytes · CPC title

• B01D69/02

  characterised by their properties · CPC title

• H01M10/056 Primary

  characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes · CPC title

• H01M10/052

  Li-accumulators · CPC title