Method of manufacturing an electrode, corresponding electrode and battery comprising such an electrode

Abstract

A method of manufacturing an electrode, including: a) depositing catalytic growth seeds on an electrically conducting support by aerosol spraying, b) growth of oriented carbon nanotubes on the basis of the deposition of the catalytic growth seeds, c) a deposition of sulphur on the oriented carbon nanotubes formed in b), and d) a deposition of a layer of carbon on the sulphur. An electrode, as well as to a battery including such an electrode, includes an electrically conducting support and oriented carbon nanotubes disposed on the surface of the electrically conducting support and covered at least partly by sulphur, the oriented carbon nanotubes exhibiting a length of greater than 20 m, or greater than 50 m.

Claims

1. A method for fabricating an electrode, comprising: a) aerosol spraying a plurality of catalytic growth seeds onto an electrically-conducting substrate, b) growing a plurality of oriented carbon nanotubes, each of the oriented carbon nanotubes starting from a respective one of said catalytic growth seeds, c) depositing sulfur onto each of the oriented carbon nanotubes formed in the step b), and d) depositing a layer of carbon onto the sulfur of each respective oriented carbon nanotube, after the step c).

2. The method as claimed in claim 1, wherein the electrically-conducting substrate is an aluminum substrate.

3. The method as claimed in claim 1, wherein prior to the step a), a layer of aluminum is deposited onto a substrate in order to form the electrically-conducting substrate.

4. The method as claimed in claim 1, wherein between the step c) and the step d), heating the electrode such that the sulfur melts on the surface of the carbon nanotubes.

Description

EXAMPLE

(1) One exemplary embodiment of the method has been implemented with the following parameters. In this example, the electrically-conducting substrate comprises a substrate made of stainless steel 1 and a layer of aluminum 2. The thin layer of aluminum 2 has a thickness of 30 nm and is deposited onto the substrate 1, by physical vapor deposition by means of an evaporator.

(2) The catalytic growth seeds 3 are deposited onto the layer of aluminum 2. For this purpose, a solution of iron chloride is prepared by solubilization of FeCl.sub.3.6H.sub.2O in ethanol, to a concentration in the range between 5.10.sup.2 mol.Math.L.sup.1 and 5.10.sup.4 The solution of iron chloride is then atomized in the form of micrometer-sized droplets by means of an atomization valve with a flow rate equal to 2 mL.Math.min.sup.1, then is carried by a flow of nitrogen toward the surface of the layer of aluminum 2 placed at a distance of around 11 cm and heated to a temperature of 120 C. The quantity of solution of iron chloride atomized is 30 mL for a sample surface area of 80 by 80 mm.sup.2.

(3) The synthesis of the carbon nanotubes 4 is subsequently carried out by chemical vapor deposition (CVD) at 600 C. by means of a precursor mixture CH.sub.4/H.sub.2 (50:50). The pressure in the CVD reactor is fixed at 50 mbar and the total gas flow at 100 sccm (standard cubic centimeters per minute). A hot filament of tungsten having a power of 205 W is used for dissociating, upstream, the hydrogen and the methane.

(4) The coating of sulfur 5 is then deposited on the carbon nanotubes 4. The solution of sulfur used for the deposition is a solution of sulfur at 1% by weight dissolved in toluene, and is atomized by aerosol spray onto the carbon nanotubes 4.

(5) Lastly, the graphitic carbon is deposited by plasma-enhanced vapor deposition (PECVD) in which the plasma is a DC discharge with a power of 100 W. The deposition is carried out at a temperature of 400 C., under a reduced pressure of 2 mbar of a mixture of ethanol and isopropanol.

(6) An electrode exhibiting the desired electrical properties and designed for use in a lithium-ion battery is thus obtained.