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CN-122010083-A - Method for producing silicon-carbon composite materials

CN122010083ACN 122010083 ACN122010083 ACN 122010083ACN-122010083-A

Abstract

A method for preparing a carbon-silicon composite material comprising a carbon-based material and a silicon nanomaterial, in particular nanowires or nanoislands, wherein the method is carried out in a rotating tubular chamber of a reactor.

Inventors

  • Olga Burchak
  • Pierre Lasselge

Assignees

  • 恩维雷斯公司

Dates

Publication Date
20260512
Application Date
20220520
Priority Date
20210528

Claims (15)

  1. 1. A process for preparing a carbon-silicon composite, wherein the process is carried out in a tubular chamber of a reactor, wherein the tubular chamber is rotatable about its longitudinal axis (X-X), the process comprising: (1) Introducing at least a carbon-based material comprising a carbon support and optionally a catalyst into the tubular chamber; (2) The tubular chamber is heated under a carrier gas flow, (3) The tubular chamber is rotated so that, (4) A reactive silicon-containing gas mixture is introduced into a rotating tubular chamber, (5) Heat treatment is carried out in a rotating tubular chamber at a temperature of 200 ℃ to 900 ℃ under a flow of a gas mixture containing reactive silicon at a pressure of greater than 1.02X10 5 Pa or equal to 1.02X10 5 Pa, (6) The product obtained is recovered and the product obtained is recovered, It will be appreciated that step (3) may begin either before or after step (1) or step (2).
  2. 2. The method of claim 1, wherein the pressure of step (5) is from 1.05x10 5 Pa to 10 6 Pa.
  3. 3. The method of claim 1 or claim 2, wherein the temperature of step (5) is from 350 ℃ to 850 ℃.
  4. 4. A method according to any one of the preceding claims, wherein the carbon-based material is selected from graphite, graphene, carbon, preferably graphite powder having an average particle size of 0.01 μm to 50 μm.
  5. 5. The method of any one of the preceding claims, wherein the carbon-based material has catalyst particles on its surface.
  6. 6. The method of any one of the preceding claims, wherein the catalyst is selected from the group consisting of metals, bimetallic compounds, metal oxides, metal nitrides, metal salts, and metal sulfides.
  7. 7. The method of any of the preceding claims, wherein the reactive silicon-containing gas mixture stream comprises at least a reactive silicon species and a carrier gas.
  8. 8. A method according to any one of the preceding claims, wherein the reactive silicon species is selected from silane compounds, preferably the reactive silicon species is silane SiH 4 .
  9. 9. The method according to any of the preceding claims, wherein the ratio of the volume of the carbon-based material comprising the carbon support and optionally the catalyst to the volume of the tubular chamber is 10% to 60%, more preferably 20% to 50%, still more preferably 30% to 50%.
  10. 10. The method according to any of the preceding claims, wherein in step (5) the flow rate of the reactive silicon containing gas mixture is from 0.1SLM to 50SLM (standard cubic per minute), more preferably from 0.5SLM to 40SLM.
  11. 11. The method of any one of the preceding claims, wherein the rotational speed of the tubular chamber is from 1RPM to 40RPM (revolutions per minute).
  12. 12. The method according to any of the preceding claims, wherein the method comprises applying at least one of the following cycles after step (6): (1') reloading the tubular chamber with fresh carbon-based material, (2') Heating the tubular chamber under a carrier gas flow, (3') Rotating the tubular chamber, (4') Introducing a reactive silicon-containing gas mixture into a rotating tubular chamber, (5') Heat treatment in a rotating tubular chamber under a flow of a reactive silicon-containing gas mixture at a temperature of 200 ℃ to 900 ℃ at a pressure of greater than 1.02X10 5 Pa or equal to 1.02X10 5 Pa, (6') Recovering the resulting product.
  13. 13. A method according to any of the preceding claims, wherein the silicon-carbon composite comprises a carbon-based material and a nano-silicon material, preferably the nano-silicon material is a nanowire or a nano-island, even more preferably a nanowire.
  14. 14. A method of preparing an electrode comprising a current collector, the method comprising (i) carrying out the method for preparing a carbon-silicon composite according to any one of claims 1 to 13, and (ii) covering at least one surface of the current collector with a composition comprising the carbon-silicon composite as an electrode active material.
  15. 15. A method of manufacturing an energy storage device, such as a lithium secondary battery, comprising a cathode, an anode and a separator arranged between the cathode and the anode, wherein the method comprises carrying out the method of claim 14 for manufacturing at least one electrode, preferably the anode.

Description

Method for producing silicon-carbon composite materials The application is a divisional application of Chinese application patent application with the application number 202280038260.0, the application date 2022, the 5 th month and 20 th day and the application name of 'method for preparing silicon-carbon composite materials'. Technical Field The present invention relates to a process for preparing a composite carbon-silicon material comprising a carbon-based material and a silicon nanomaterial, in particular nanowires or nanoislands, which process is carried out in a tubular chamber of a rotary reactor at a pressure above atmospheric pressure. The invention also relates to a method for manufacturing an electrode of a lithium ion battery. Background Since commercialization in 1991, lithium Ion Battery (LIB) technology has continuously improved its ability to store energy. But new generation LIBs require higher energy densities at a given battery capacity (kWh/L) and lower price ($/kWh), especially for electric car applications. Current battery active materials (including anode and cathode components) have reached theoretical limits and battery manufacturers need more efficient materials to meet market demands. Graphite, which is currently used as the almost exclusive anode material, is a weak link in the cell and occupies more space than any other component. Over the last two decades, several anode materials have been developed with improved storage capacity. Among them, silicon (Si) is the most promising candidate as a novel anode material because it can store approximately 10 times more energy than graphite. In parallel with the high theoretical specific capacity, silicon has a high volume expansion, resulting in poor stability during lithiation and decay. Silicon nanowires (sinws) are excellent candidates for LIB anode materials in terms of specific capacity and cycle life, as sinws exhibit perfect strain and volume tuning properties. High performance lithium battery anodes using silicon nanowires grown directly on a current collector have been disclosed in Nature Nanotechnology,2008,31-35. However, this new electrode technology requires serious efforts from battery manufacturers to match current battery production lines. In contrast, the co-utilization of silicon nanowires and graphite/carbon can be one of the preferred strategies as a complete "drop". The industrial manufacture of such composites at acceptable prices is a significant challenge for the battery market. The different techniques for SiNW preparation are largely divided into two synthetic methods, bottom-up (growth of nanowires from elemental silicon) and top-down (bulk silicon etching). The top-down method is characterized by a large waste of starting silicon and the inevitable use of dangerous chemicals. Bottom-up techniques are typically based on Chemical Vapor Deposition (CVD) and can produce nanowires of high quality. The "fixed bed" CVD equipment currently used for SiNW growth results in limited contact between the 2D surface decorated by the metal nano-seeds and the gas precursor, and therefore can only be prepared in small amounts, which is insufficient to meet the market demand. Several attempts have been made to synthesize SiNW using a vertical "fluidized bed" CVD reactor to increase the contact surface in 3D form (e.g., US 2011/0309306). Unfortunately, the use of conventional "fluidized bed" CVD reactors on an industrial scale has shown very limited technical and economic viability because 1/as the production scale increases, the volumetric process rate (product mass per reactor volume) decreases and 2/requires the handling of extremely large amounts of reactants/carrier gases and complexes, thus the cost of separating gas and nano-and micro-sized objects on an industrial scale is high. WO 2018/013991 discloses the preparation of carbon SiNW composites in a mechanically rotating fluidized bed reactor, which can be used in batch mode or semi-continuous mode. The method is based on the use of a drum filled with a carbon-based material. The process is carried out at low pressure. The method provides a kilogram grade material comprising up to 32 mass% Si. There are major limitations to this approach in that the reaction zone of the CVD chamber is limited by the reduced drum size, and from a technical, procedural and economic standpoint, the track, gas input, gas output and gear system, and the pressure regulation means required to connect and control the drum result in complex apparatus. The system is equipped with a cyclone separator for collecting elutriated particles of a size greater than 5 μm, thereby limiting the range of powders that can be used in the process. Another example of the preparation of carbon-SiNW composites has been recently reported (Energy & Fuels,2021,35275-2765). The authors demonstrate the possibility of preparing SiNW/graphite composites from chloromethylsilane and graphite powder using a simple rotary furn