Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/14—Metallic material, boron or silicon
  • C23C14/16—Metallic material, boron or silicon on metallic substrates or on substrates of boron or silicon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
  • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/58—After-treatment
  • C23C14/5806—Thermal treatment
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/58—After-treatment
  • C23C14/5806—Thermal treatment
  • C23C14/5813—Thermal treatment using lasers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/04—Processes of manufacture in general
  • H01M4/0402—Methods of deposition of the material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/04—Processes of manufacture in general
  • H01M4/0402—Methods of deposition of the material
  • H01M4/0421—Methods of deposition of the material involving vapour deposition
  • H01M4/0423—Physical vapour deposition
  • H01M4/0426—Sputtering
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/04—Processes of manufacture in general
  • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/362—Composites
  • H01M4/366—Composites as layered products
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
  • H01M4/386—Silicon or alloys based on silicon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/661—Metal or alloys, e.g. alloy coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/027—Negative electrodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the invention relates to a method for producing a silicon electrode as an anode for lithium batteries, in which a first silicon layer is deposited on a substrate, preferably copper, and is then subjected to short-term annealing.
• Batteries are electrochemical energy stores and are divided into primary and secondary batteries.
• Battery is the generic term for interconnected cells.
• Cells are galvanic units consisting of two electrodes, electrolyte, separator and cell case.
• Figure 1 shows an exemplary structure and the function of a lithium-ion cell during the discharge process. The components of a cell are briefly explained below.
• the anode of the Li-ion cell can consist of a copper foil as the collector and a layer of carbon as the active material.
• natural or artificial graphite is used as the carbon compound, since it has a low electrode potential and exhibits low volume expansion during the charging and discharging process. During the charging process, lithium ions are reduced and embedded in the graphite layers.
• the cathode In lithium-ion battery designs, the cathode typically supplies the lithium atoms for charging and discharging in the anode, so the battery capacity is limited by the cathode capacity.
• typical cathode materials previously used are e.g. B. Li(Ni,Co,Mn)O2 and LiFePCg. Because the cathode is made up of lithium metal oxides, the capacity can only be increased to an insignificant extent.
• silicon-based nanoparticles and nanowires have more stable silicon structures with regard to the change in volume of the silicon after the incorporation of the lithium up to a certain Si structure size, as described in the publication M. Green, E. Fielder, B. Scrosati, M. Wachtier and J.S. Moreno: Structured Silicon anodes for lithium battery applications, Electrochem. Solid-State Lett, 6, A75-A79 (2003). Ipm is considered to be the structural limit for amorphous and 100nm for crystalline silicon, so that a uniform volume change can take place.
• the Si anodes that can be produced using the method known from WO 2017/140581 A1 are a mixture of silicon, pure metals and silicides if only a copper foil is used as the substrate and on which a silicon layer is deposited, i. H . a structure of copper, copper silicide and silicon is formed.
• the advantages of Si anodes produced in this way compared to Si anodes made from nanoparticles or nanoparticles are high electrical conductivity compared to pure silicon and also conventional graphite, since silicides have an approx. have two orders of magnitude better electrical conductivity than graphite.
• the entire copper substrate e.g. B. a copper foil, react with the silicon completely to form copper silicide and result in the loss of the lithium battery's current collector.
• Short-term tempering is understood to mean, in particular, flash lamp tempering and/or laser tempering.
• the flash lamp annealing takes place with a pulse duration or annealing time in the range from 0.3 to 20 ms and a pulse energy in the range from 0.3 to 100 J/cm 2 .
• the annealing time is adjusted from 0.01 to 100 ms by the scanning speed of the local heating site to produce an energy density of 0.1 to 100 J/cm 2 .
• the heating ramps achieved in the short-term tempering are in the range of 10 A 4-10 A 7 K/s required for the process. Flashlamp annealing uses a spectrum in the visible wavelength range for this, whereas laser annealing uses discrete wavelengths in the infrared (TR) to ultraviolet (UV) spectrum.
• TR infrared
• UV ultraviolet
• the described first embodiment variant of the method according to the invention can be claimed as a pre-process in combination with the other following ones Process steps are used because the roughening of the surface, as an example of a positive effect of a layer-wise separate reaction, creates good adhesion for further layers, the growth of columnar structures is promoted, so that better ion conductivity can be achieved as well as the copper content can be well controlled for follow-up processes.
• the first layer can consist of Ipm silicon, which reacts completely with the copper substrate to form CuSi x , mostly CuaSi. This results in a roughening of the surface and very good adhesion to the copper substrate.
• the reaction proceeds in a controlled manner through the selection of the process parameters of the short-time annealing using the method according to the invention, and a loss of the current collector is prevented.
• the strong adhesion of the subsequently to be realized layer structure on the copper substrate can also be realized by mechanical roughening or by means of a material other than silicon.
• WO 2017/140581 A1 only one silicon layer is deposited, which is subjected to flash lamp annealing.
• the necessary Si layer thickness of up to 10 pm for battery applications is deposited on the substrate in one process step and tempered by the flash lamp.
• the layers produced in this way are brittle and easily flake off or react completely with the copper of the substrate, which means that no storable silicon remains.
• the insertion of an additional material in the layers of the silicon layer structure has the advantage that the copper of the copper substrate only reacts to a very small extent with the applied layers, which in particular ensures good adhesion, and on the other hand the copper of the current collector, by preventing a Reaction with the further deposited layers, is not degraded.
• nickel silicide initially forms during the short-term annealing. If flash lamp annealing is used as short-term tempering, the nickel is replaced with copper again using a flash lamp, which can have a flash duration of between 0.2 ms and 20 ms and an energy density of 0.6 J/cm2 and 160 J/cm2, and nickel remains pure metal in the layer. Since nickel silicide has a smaller density, Cu silicide having a smaller density is formed. This improves compensation in Li intercalation.
• the short-term annealing is carried out using a laser (laser annealing)
• this is done with an annealing time in the range from 0.01 ms to 100 ms by setting a scanning speed of a local heating point and an energy density in the range from 0.1 to 100 J/cm 2 and preheating or cooling in the range of 4°C to 200°C. Since it is a non-equilibrium process, which only occurs in the ms- area is feasible, the use of a flash lamp or laser is required.
• the flash lamps preferably consist of gas discharge lamps, which emit a major part of the radiation in the wavelength range between the visible range and the infrared range (400 nm - 800 nm) and work with a possible total power of approx. 12 MW in less than 20 ms and thus the sample surfaces on a temperature of up to 2000°C can be brought.
• the flashlamp anneal serves to promote the metal-induced layer exchange process, also known as metal-induced crystallization.
• the deposition of an additional metal layer on the silicon layer thus has the advantage that the silicide formation reaction at the interface with the copper foil and additionally takes place at the interface of the metal layer applied on top. This ensures good adhesion between the copper foil and the silicon layer and at the same time the reaction of Cu and Si to form copper silicide is controlled by the metal layer on the top.
• a metal layer can improve surface conductivity. A high electrical conductivity of the battery is important for fast charging/discharging processes, as well as that the Li+ ions can penetrate well into the layers. Therefore, all layers and interfaces must be as conductive as possible.
• doped Si can be very conductive, but react with the electrolyte or with decomposition products, so that SiO2 (very good insulator) or even Li 4 SiO4 (Li silicate) is formed.
• Li silicate is a very good insulator and there are losses of Li due to tight bonding. Therefore, this must be prevented in the overall construction of the anode, e.g. B. non-closed/porous surfaces, conductive interfaces, soluble/soft protective layers. This can be prevented by an additional metal layer at the interface.
• a layer other than silicon preferably nickel (Ni) and/or copper (Cu), is deposited on the copper substrate.
• Ni nickel
• Cu copper
• FIG. 3 shows a multilayer structure produced according to the method according to the invention for stabilizing the Si layer system: a) REM-SE photograph, b) REM-BSE photograph;
• the method according to the invention represents a very simple process with which very good adhesion at the interface between the Cu collector and the silicon and a very good electrical transition are achieved.
• the deposited silicon and the copper which comes from the copper collector, no additional material is required.
• the battery capacity can thus be further increased compared to lithium batteries that have been produced using a conventional method.
• the deposition of another silicon layer with Subsequent short-term tempering can be used as a pre-process in combination with the deposition of a thin layer of a further layer for the silicon layer structure, since the roughening of the surface creates good adhesion for further layers, the growth of columnar structures is promoted, so that better ion conduction capability can be achieved and the copper content can be well controlled for subsequent processes.

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• Chemical & Material Sciences (AREA)
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• 2022
  • 2022-08-09 JP JP2024501111A patent/JP2024528811A/ja active Pending
  • 2022-08-09 KR KR1020247007442A patent/KR20240039193A/ko active Pending
  • 2022-08-09 EP EP22765029.8A patent/EP4385080A1/de active Pending
  • 2022-08-09 US US18/682,029 patent/US20240417843A1/en active Pending
  • 2022-08-09 CN CN202280055553.XA patent/CN117795700A/zh active Pending
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