CA3116784A1 - Method for forming silicon anodes - Google Patents
Method for forming silicon anodes Download PDFInfo
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- CA3116784A1 CA3116784A1 CA3116784A CA3116784A CA3116784A1 CA 3116784 A1 CA3116784 A1 CA 3116784A1 CA 3116784 A CA3116784 A CA 3116784A CA 3116784 A CA3116784 A CA 3116784A CA 3116784 A1 CA3116784 A1 CA 3116784A1
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- Canada
- Prior art keywords
- metallurgical silicon
- metal
- anode
- ceramic layer
- silicon
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 72
- 239000010703 silicon Substances 0.000 title claims abstract description 69
- 238000000034 method Methods 0.000 title claims description 47
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title description 54
- 229910052751 metal Inorganic materials 0.000 claims abstract description 42
- 239000002184 metal Substances 0.000 claims abstract description 42
- 239000000919 ceramic Substances 0.000 claims abstract description 22
- 238000000151 deposition Methods 0.000 claims abstract description 16
- 238000005530 etching Methods 0.000 claims abstract description 14
- 239000002245 particle Substances 0.000 claims description 30
- 238000000231 atomic layer deposition Methods 0.000 claims description 18
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 12
- 239000003792 electrolyte Substances 0.000 claims description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 229910001416 lithium ion Inorganic materials 0.000 claims description 8
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 238000003486 chemical etching Methods 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 6
- 239000010936 titanium Substances 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 5
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 229910044991 metal oxide Inorganic materials 0.000 claims description 5
- 150000004706 metal oxides Chemical class 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 4
- 239000011230 binding agent Substances 0.000 claims description 4
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 4
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 4
- 239000004332 silver Substances 0.000 claims description 4
- 229910001928 zirconium oxide Inorganic materials 0.000 claims description 4
- 239000004411 aluminium Substances 0.000 claims description 3
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 239000010931 gold Substances 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 3
- 229910052697 platinum Inorganic materials 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 2
- 239000011856 silicon-based particle Substances 0.000 abstract description 11
- 229910021426 porous silicon Inorganic materials 0.000 abstract description 7
- 239000010410 layer Substances 0.000 description 14
- 230000001351 cycling effect Effects 0.000 description 12
- 230000008021 deposition Effects 0.000 description 10
- 239000002105 nanoparticle Substances 0.000 description 8
- GETQZCLCWQTVFV-UHFFFAOYSA-N trimethylamine Chemical compound CN(C)C GETQZCLCWQTVFV-UHFFFAOYSA-N 0.000 description 8
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- -1 Ag+ ions Chemical class 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 239000011247 coating layer Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 239000002243 precursor Substances 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 238000013507 mapping Methods 0.000 description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 238000004146 energy storage Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 239000011863 silicon-based powder Substances 0.000 description 3
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 3
- MNWRORMXBIWXCI-UHFFFAOYSA-N tetrakis(dimethylamido)titanium Chemical compound CN(C)[Ti](N(C)C)(N(C)C)N(C)C MNWRORMXBIWXCI-UHFFFAOYSA-N 0.000 description 3
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 229910004074 SiF6 Inorganic materials 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000005524 ceramic coating Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002923 metal particle Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- 241000252506 Characiformes Species 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 229910001290 LiPF6 Inorganic materials 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 229910010303 TiOxNy Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 238000000840 electrochemical analysis Methods 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 238000006138 lithiation reaction Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000005543 nano-size silicon particle Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 238000005549 size reduction Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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- 239000001117 sulphuric acid Substances 0.000 description 1
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- 238000002525 ultrasonication Methods 0.000 description 1
Classifications
-
- 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
- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/134—Electrodes based on metals, Si or alloys
-
- 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
-
- 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
Abstract
-15-ABSTRACT A nano-porous Si particle is produced by providing a quantity of metallurgical silicon, depositing a quantity of a metal on the surface of the quantity of metallurgical silicon to produce a metal deposited metallurgical silicon, etching the metal deposited metallurgical silicon and depositing a ceramic layer on the etched metal deposited metallurgical silicon. The nano-porous Si particle may be formed into an anode and/or incorporated into in a battery. Date Recue/Date Received 2021-04-30
Description
METHOD FOR FORMING SILICON ANODES
BACKGROUND
1. Technical Field This disclosure relates generally to batteries and in particular to method for forming silicon anodes.
BACKGROUND
1. Technical Field This disclosure relates generally to batteries and in particular to method for forming silicon anodes.
2. Description of Related Art Lithium ion batteries are one of the most important energy storage technologies, for much of the world's energy storage market ranging from the consumer electronics to electric vehicles or distributed energy storage systems. The increasing demands from end users have stimulated the development of lithium ion batteries with higher energy and power density, better rate capacity, and longer cycling life.
Silicon (Si) has been long considered as the most promising anode alternative for use in lithium ion batteries due to its high theoretical capacity, moderate working voltage and large abundance on the earth. Despite significant advances, Si-based anodes still face great problems towards practical applications. One problem is the lack of a scalable and low-cost fabrication method for nanostructured Si.
Current fabrication methods have not adequately addressed a cost-effective way to reduce the cost of Si anode, due to the process complexity and/or high-cost starting materials. For example, chemical vapor deposition is able to deposit Si nanoparticles with less than 100 nm, but requires high temperature and expensive precursors (such as Si2F16, SiH4). On the other hand, top-down approaches are mostly based on high-cost electronic-grade Si (n-type, p-type, boron-doped, purity >
99.99999%) as feedstock, and involve the use of template or lithography steps that increases process complexity. Another problem is that most Si anodes reported so far are based on half cells (Li metal as counter electrode), and the use of excess Li metal in half cells "shield" the efficiency and cycling problems of Si anode. It is challenging to assess their feasibility in full cells which are required in practical applications.
Date Recue/Date Received 2021-04-30 SUMMARY OF THE DISCLOSURE
According to a first embodiment, there is disclosed a method for producing an anode for a battery comprising providing a quantity of metallurgical silicon, etching the metal deposited metallurgical silicon and depositing a ceramic layer on the etched metal deposited metallurgical silicon. The method may further comprise depositing a quantity of a metal on the surface of the quantity of metallurgical silicon to produce a metal deposited metallurgical silicon before etching.
The method may further comprise reducing the size of the metallurgical silicon into particles having a diameter selected to be between 0.5 and 50 mm. The reducing may comprise mechanically reducing. The mechanical reducing may comprise crushing.
The metal may be selected from the group comprising silver, gold, platinum, nickel and iron. The metallurgical silicon may be immersed in a solution containing a salt of the metal. The metal may be deposited on to the surface of the metallurgical silicon through a galvanic displacement reaction.
The ceramic layer may comprise a metal oxide. The metal oxide may be selected from the group consisting of aluminum oxide, titanium oxide, zirconium oxide and silicon oxide. The ceramic layer may comprise a metal oxynitride. The metal oxynitride is selected from the group consisting of aluminium oxynitride, titanium oxynitride and tantalum oxynitride.
The ceramic layer may be selected to have a thickness between 1 and 20 nm.
The ceramic layer may be formed by atomic layer deposition.
According to a further embodiment, there is disclosed an anode for a battery comprising at least one particle of porous metallurgical silicon having a ceramic layer formed thereover.
Date Recue/Date Received 2021-04-30
Silicon (Si) has been long considered as the most promising anode alternative for use in lithium ion batteries due to its high theoretical capacity, moderate working voltage and large abundance on the earth. Despite significant advances, Si-based anodes still face great problems towards practical applications. One problem is the lack of a scalable and low-cost fabrication method for nanostructured Si.
Current fabrication methods have not adequately addressed a cost-effective way to reduce the cost of Si anode, due to the process complexity and/or high-cost starting materials. For example, chemical vapor deposition is able to deposit Si nanoparticles with less than 100 nm, but requires high temperature and expensive precursors (such as Si2F16, SiH4). On the other hand, top-down approaches are mostly based on high-cost electronic-grade Si (n-type, p-type, boron-doped, purity >
99.99999%) as feedstock, and involve the use of template or lithography steps that increases process complexity. Another problem is that most Si anodes reported so far are based on half cells (Li metal as counter electrode), and the use of excess Li metal in half cells "shield" the efficiency and cycling problems of Si anode. It is challenging to assess their feasibility in full cells which are required in practical applications.
Date Recue/Date Received 2021-04-30 SUMMARY OF THE DISCLOSURE
According to a first embodiment, there is disclosed a method for producing an anode for a battery comprising providing a quantity of metallurgical silicon, etching the metal deposited metallurgical silicon and depositing a ceramic layer on the etched metal deposited metallurgical silicon. The method may further comprise depositing a quantity of a metal on the surface of the quantity of metallurgical silicon to produce a metal deposited metallurgical silicon before etching.
The method may further comprise reducing the size of the metallurgical silicon into particles having a diameter selected to be between 0.5 and 50 mm. The reducing may comprise mechanically reducing. The mechanical reducing may comprise crushing.
The metal may be selected from the group comprising silver, gold, platinum, nickel and iron. The metallurgical silicon may be immersed in a solution containing a salt of the metal. The metal may be deposited on to the surface of the metallurgical silicon through a galvanic displacement reaction.
The ceramic layer may comprise a metal oxide. The metal oxide may be selected from the group consisting of aluminum oxide, titanium oxide, zirconium oxide and silicon oxide. The ceramic layer may comprise a metal oxynitride. The metal oxynitride is selected from the group consisting of aluminium oxynitride, titanium oxynitride and tantalum oxynitride.
The ceramic layer may be selected to have a thickness between 1 and 20 nm.
The ceramic layer may be formed by atomic layer deposition.
According to a further embodiment, there is disclosed an anode for a battery comprising at least one particle of porous metallurgical silicon having a ceramic layer formed thereover.
Date Recue/Date Received 2021-04-30
-3-The particle of porous metallurgical silicon may be formed by metal assisted chemical etching a quantity of metallurgical silicon. The ceramic layer may be formed by atomic layer deposition. The ceramic layer may be selected to have a thickness of between 1 and 20 nm. A plurality of particles of porous metallurgical silicon may be secured in a binder.
According to a further embodiment, there is disclosed a lithium ion battery comprising a cathode, an anode comprising at least one particle of porous metallurgical silicon having a ceramic layer formed thereover and a non-aqueous lithium containing electrolyte between the cathode and anode.
Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings constitute part of the disclosure. Each drawing illustrates exemplary aspects wherein similar characters of reference denote corresponding parts in each view, Figure 1 is a flowchart illustrating one exemplary process of the present disclosure.
Figure 2 depicts a quantity of metallurgical silicon for use in the exemplary process of the present disclosure.
Figure 3 depicts a plurality of particles of mechanically reduced metallurgical silicon in accordance with the exemplary process of the present disclosure.
Figure 4 depicts a cleaned plurality of particles of mechanically reduced metallurgical silicon in accordance with the exemplary process of the present disclosure.
Figure 5 is an image of the surface of a particle deposited with a metal in accordance with the exemplary process of the present disclosure.
Figure 6 is an image of the etched surface of the particle of Figure 5 in accordance with the exemplary process of the present disclosure.
Date Recue/Date Received 2021-04-30
According to a further embodiment, there is disclosed a lithium ion battery comprising a cathode, an anode comprising at least one particle of porous metallurgical silicon having a ceramic layer formed thereover and a non-aqueous lithium containing electrolyte between the cathode and anode.
Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings constitute part of the disclosure. Each drawing illustrates exemplary aspects wherein similar characters of reference denote corresponding parts in each view, Figure 1 is a flowchart illustrating one exemplary process of the present disclosure.
Figure 2 depicts a quantity of metallurgical silicon for use in the exemplary process of the present disclosure.
Figure 3 depicts a plurality of particles of mechanically reduced metallurgical silicon in accordance with the exemplary process of the present disclosure.
Figure 4 depicts a cleaned plurality of particles of mechanically reduced metallurgical silicon in accordance with the exemplary process of the present disclosure.
Figure 5 is an image of the surface of a particle deposited with a metal in accordance with the exemplary process of the present disclosure.
Figure 6 is an image of the etched surface of the particle of Figure 5 in accordance with the exemplary process of the present disclosure.
Date Recue/Date Received 2021-04-30
-4-Figures 7A-F are images of the surface of the during the exemplary process of the present disclosure.
Figure 8A-8D are graphs illustrating the cycling performance of batteries utilizing an anode produced using exemplary processes of the present disclosure.
DETAILED DESCRIPTION
Aspects of the present disclosure are now described with reference to exemplary apparatuses, methods and systems. Referring to Figure 1, an exemplary process for forming nano-porous silicon (Si) according to a first embodiment is shown generally at 10. In particular, the present method provides a cost-effective route to obtain nano-porous Si particles by scalable metal-assisted chemical etching (MCE) procedure using inexpensive metallurgical silicon and further introducing of an ultrathin ceramic or other protective layer deposited by atomic layer deposition (ALD) to stabilize the Si anode surface. The combination of the nano-porous structure and nanoscale ALD coating layer can not only benefit for the electrolyte filtration but also accommodate large mechanical strains during the lithium insertion and extraction processes, thus leading to a significant improvement in electrochemical performance.
As illustrated in Figure 1, the present method 10 utilizes a quantity of metallurgical silicon 8 as an initial material. It will be appreciated that metallurgical silicon is commonly formed by reducing naturally occurring silica to silicon however not to a purity level typically required for electronics production. The metallurgical silicon 8 is then mechanically reduced in size to a particle size between 0.5 and 50 mm in step 12. In practice it has been found for use in battery anode production a size of approximately 5 mm has been useful. The size reduction of the metallurgical silicon may be accomplished by any known means and in particular may be performed by mechanical reduction including crushing. Thereafter in step 14, the size reduced metallurgical silicon is cleaned so as to provide a clean surface for subsequent steps. In particular, the size-reduced metallurgical silicon may be Date Recue/Date Received 2021-04-30
Figure 8A-8D are graphs illustrating the cycling performance of batteries utilizing an anode produced using exemplary processes of the present disclosure.
DETAILED DESCRIPTION
Aspects of the present disclosure are now described with reference to exemplary apparatuses, methods and systems. Referring to Figure 1, an exemplary process for forming nano-porous silicon (Si) according to a first embodiment is shown generally at 10. In particular, the present method provides a cost-effective route to obtain nano-porous Si particles by scalable metal-assisted chemical etching (MCE) procedure using inexpensive metallurgical silicon and further introducing of an ultrathin ceramic or other protective layer deposited by atomic layer deposition (ALD) to stabilize the Si anode surface. The combination of the nano-porous structure and nanoscale ALD coating layer can not only benefit for the electrolyte filtration but also accommodate large mechanical strains during the lithium insertion and extraction processes, thus leading to a significant improvement in electrochemical performance.
As illustrated in Figure 1, the present method 10 utilizes a quantity of metallurgical silicon 8 as an initial material. It will be appreciated that metallurgical silicon is commonly formed by reducing naturally occurring silica to silicon however not to a purity level typically required for electronics production. The metallurgical silicon 8 is then mechanically reduced in size to a particle size between 0.5 and 50 mm in step 12. In practice it has been found for use in battery anode production a size of approximately 5 mm has been useful. The size reduction of the metallurgical silicon may be accomplished by any known means and in particular may be performed by mechanical reduction including crushing. Thereafter in step 14, the size reduced metallurgical silicon is cleaned so as to provide a clean surface for subsequent steps. In particular, the size-reduced metallurgical silicon may be Date Recue/Date Received 2021-04-30
-5-degreased in known degreasing compositions including acetone and isopropyl, water sulphuric acid, hydrogen peroxide and the like.
The cleaned metallurgical silicon particles then have nanoparticles of a metal deposited on the surface thereof in step 16. In particular, the metallic deposition may be accomplished by known methods including immersion in a solution of the metallic salt and deposition on the surface by a galvanic displacement reaction although it will be appreciated that other methods, such as, by way of non-limiting example, physical vapour deposition could also be utilized. In the present disclosure, the metal utilized is silver (Ag) although it will be appreciated that other metals may also be utilized, such as, by way of non-limiting example, gold, platinum, nickel or iron. After the application of metal particles, the surface of the particles may again be optionally cleaned or rinsed in step 18 to remove any residual metal or other materials.
The metal deposited metallurgical silicon may then be etched by any suitable means in step 20. In particular, the etching may be performed in a suitable acid, such as, by way of non-limiting example, hydrofluoric acid and hydrogen peroxide. Alternatively the etching may be performed using other means including without limitation electrochemical etching without the addition of the metal particles. The working principle of chemical etching is based on a local oxidation of the Si surface by a metal catalyst and H202, and the subsequent dissolution of silicon oxide in an HF solution. In this galvanic reaction, metal Ag nanoparticles act as a local cathode and a catalyst to promote the reduction of H202 and produce free holes at the interface of Ag and Si, while the Si surface serves as anode. On the anode, the Si is dissolved continuously by transferring electrons to the Ag particles at the interface of Ag and Si in order to reduce H202 to H20. At the cathode, Ag particles are oxidized into Ag+ ions by H202, and the Ag+ ions are reduced to Ag by accepting electrons from Si. With this repeated procedure, the Si underneath the Ag particles is continuously etched down to make porous structures. The cathode, anode and total chemical reactions can be listed as the following:
Cathode:
Date Recue/Date Received 2021-04-30
The cleaned metallurgical silicon particles then have nanoparticles of a metal deposited on the surface thereof in step 16. In particular, the metallic deposition may be accomplished by known methods including immersion in a solution of the metallic salt and deposition on the surface by a galvanic displacement reaction although it will be appreciated that other methods, such as, by way of non-limiting example, physical vapour deposition could also be utilized. In the present disclosure, the metal utilized is silver (Ag) although it will be appreciated that other metals may also be utilized, such as, by way of non-limiting example, gold, platinum, nickel or iron. After the application of metal particles, the surface of the particles may again be optionally cleaned or rinsed in step 18 to remove any residual metal or other materials.
The metal deposited metallurgical silicon may then be etched by any suitable means in step 20. In particular, the etching may be performed in a suitable acid, such as, by way of non-limiting example, hydrofluoric acid and hydrogen peroxide. Alternatively the etching may be performed using other means including without limitation electrochemical etching without the addition of the metal particles. The working principle of chemical etching is based on a local oxidation of the Si surface by a metal catalyst and H202, and the subsequent dissolution of silicon oxide in an HF solution. In this galvanic reaction, metal Ag nanoparticles act as a local cathode and a catalyst to promote the reduction of H202 and produce free holes at the interface of Ag and Si, while the Si surface serves as anode. On the anode, the Si is dissolved continuously by transferring electrons to the Ag particles at the interface of Ag and Si in order to reduce H202 to H20. At the cathode, Ag particles are oxidized into Ag+ ions by H202, and the Ag+ ions are reduced to Ag by accepting electrons from Si. With this repeated procedure, the Si underneath the Ag particles is continuously etched down to make porous structures. The cathode, anode and total chemical reactions can be listed as the following:
Cathode:
Date Recue/Date Received 2021-04-30
-6-H202 + 2H+ +2e- 2H20 E = 1.78 V
Anode:
Si+ 2H20 ¨. Si02 + 4H+ + 4e- E = - 0.91 V
Si02 + 6HF ¨. [SiF6]2-+ 2H20 + 2H+
Totals:
Si + 2H202 + 6F- + 4H+ [SiF6]2-+ 4H20 For the total reaction, the standard potential is 2.69 V, indicating that the etching process is highly thermodynamically favored.
In step 22, the residual nano particles may then be removed from the etched metallurgical silicon surface through the use of a suitable rinsing agent, such as water nitric acid or the like depending upon the metal used and optional mechanical agitation with ultrasonics or the like. The etched and cleaned metallurgical silicon particles then have a layer of a ceramic applied thereto through the use of atomic layer deposition or the like in step 24. In particular the protective coating layer deposited in step 24 may be selected to be a metal oxide, such as, by way of non-limiting example, Aluminum Oxide (A1203), titanium dioxide (TiO), zirconium oxide (ZrO2) or silicon oxide (5i02) or a metal oxynitride, such as, by way of non-limiting example, aluminium oxynitride (AION), titanium oxynitride (TiOxNy) or tantalum oxynitride (Ta0N).
It will be appreciated that the thickness of this layer may be varied depending on the size of the particles and the intended use of the coated particles and in particular for use in a lithium ion battery anode may be selected to be between 1 and 20 nm thick.
It will be appreciated that the process of the present disclosure provides a cost-effective route to obtain nano-porous Si particles using a scalable metal-assisted chemical etching procedure from inexpensive metallurgical silicon and further introducing of an ultrathin ceramic coating to stabilize the Si anode surface. The combination of the nano-porous structure and nanoscale ceramic coating layer may provide benefits for the electrolyte filtration but also accommodates large mechanical strains during the lithium insertion and Date Recue/Date Received 2021-04-30
Anode:
Si+ 2H20 ¨. Si02 + 4H+ + 4e- E = - 0.91 V
Si02 + 6HF ¨. [SiF6]2-+ 2H20 + 2H+
Totals:
Si + 2H202 + 6F- + 4H+ [SiF6]2-+ 4H20 For the total reaction, the standard potential is 2.69 V, indicating that the etching process is highly thermodynamically favored.
In step 22, the residual nano particles may then be removed from the etched metallurgical silicon surface through the use of a suitable rinsing agent, such as water nitric acid or the like depending upon the metal used and optional mechanical agitation with ultrasonics or the like. The etched and cleaned metallurgical silicon particles then have a layer of a ceramic applied thereto through the use of atomic layer deposition or the like in step 24. In particular the protective coating layer deposited in step 24 may be selected to be a metal oxide, such as, by way of non-limiting example, Aluminum Oxide (A1203), titanium dioxide (TiO), zirconium oxide (ZrO2) or silicon oxide (5i02) or a metal oxynitride, such as, by way of non-limiting example, aluminium oxynitride (AION), titanium oxynitride (TiOxNy) or tantalum oxynitride (Ta0N).
It will be appreciated that the thickness of this layer may be varied depending on the size of the particles and the intended use of the coated particles and in particular for use in a lithium ion battery anode may be selected to be between 1 and 20 nm thick.
It will be appreciated that the process of the present disclosure provides a cost-effective route to obtain nano-porous Si particles using a scalable metal-assisted chemical etching procedure from inexpensive metallurgical silicon and further introducing of an ultrathin ceramic coating to stabilize the Si anode surface. The combination of the nano-porous structure and nanoscale ceramic coating layer may provide benefits for the electrolyte filtration but also accommodates large mechanical strains during the lithium insertion and Date Recue/Date Received 2021-04-30
-7-extraction processes, thus leading to a significant improvement in electrochemical performance. The etched and coated particles may subsequently be mixed into a binder and applied to a current collector to form an anode for use in a battery.
Example 1 A massive metallurgical silicon (-5 cm) was firstly mechanical crushed into small particles (-5 mm) for later treatment.
Surface clean: the surface of metallurgical silicon particles was thoroughly washed by the following procedure. Firstly, the metallurgical silicon was degreased in acetone and isopropanol for 30 min, rinsed with deionized (DI) water. Secondly, they were cleaned in a piranha solution (3:1 concentrated H2504/30% H202) for 15 min at room temperature followed by rinsing by DI
water.
Ag deposition: the metallurgical silicon particle with clean surface was immersed into the solution of 10 mM AgNO3 and 5 M HF for the Ag nanoparticles deposition. Ag nanoparticles were deposited onto the surface of Si via a galvanic displacement reaction. Subsequently, excess silver precursors were completely removed by rinsing several times with DI water.
Metal-assisted chemical etching: the Ag-deposited Si were immersed into an etchant consisting of 10M HF and 0.5M H202 at 50 C for 3 h for the etching reaction. After the etching process, the Si particles were rinsed with concentrated HNO3 and large amount of DI water to remove any residual Ag nanoparticles. The nano-porous Si samples (Etched metallurgical silicon) were obtained by intensive ultrasonication.
ALD A1203 deposition: an ultrathin A1203 coating was obtained at 100 C by alternatively supplying trimethylamine (TMA) and H20 into a commercial ALD
reactor (GEMStarTm XT Atomic Layer Deposition System) with 30 ALD cycles.
Date Recue/Date Received 2021-04-30
Example 1 A massive metallurgical silicon (-5 cm) was firstly mechanical crushed into small particles (-5 mm) for later treatment.
Surface clean: the surface of metallurgical silicon particles was thoroughly washed by the following procedure. Firstly, the metallurgical silicon was degreased in acetone and isopropanol for 30 min, rinsed with deionized (DI) water. Secondly, they were cleaned in a piranha solution (3:1 concentrated H2504/30% H202) for 15 min at room temperature followed by rinsing by DI
water.
Ag deposition: the metallurgical silicon particle with clean surface was immersed into the solution of 10 mM AgNO3 and 5 M HF for the Ag nanoparticles deposition. Ag nanoparticles were deposited onto the surface of Si via a galvanic displacement reaction. Subsequently, excess silver precursors were completely removed by rinsing several times with DI water.
Metal-assisted chemical etching: the Ag-deposited Si were immersed into an etchant consisting of 10M HF and 0.5M H202 at 50 C for 3 h for the etching reaction. After the etching process, the Si particles were rinsed with concentrated HNO3 and large amount of DI water to remove any residual Ag nanoparticles. The nano-porous Si samples (Etched metallurgical silicon) were obtained by intensive ultrasonication.
ALD A1203 deposition: an ultrathin A1203 coating was obtained at 100 C by alternatively supplying trimethylamine (TMA) and H20 into a commercial ALD
reactor (GEMStarTm XT Atomic Layer Deposition System) with 30 ALD cycles.
Date Recue/Date Received 2021-04-30
-8-Example 2 PEALD metal nitride deposition: In an alternative method, metal nitrides (AIN, TiN) coating on the as-prepared etched metallic silicon are performed in a plasma-enhanced ALD system (PLEAD). ALD-AIN is deposited at temperatures of 100 C - 150 C by using trimethylamine (TMA) and plasma N2 gas (99.999%) as precursors. ALD-TiN is deposited at temperatures of 100 C - 150 C by using tetrakis(dimethylamido)titanium (TDMAT) and plasma N2 gas (99.999%) as precursors. TiN has a higher electronic conductivity than ceramics (such as A1203). The use of TD MAT, rather than TiCI4, as Ti precursor was found to be advantageous for achieving uniform and high-quality TiN thin film.
Example 3 PEALD metal oxynitride deposition: In an alternative method, Titanium oxynitride (TiON) is deposited on the as-prepared etched metallic silicon at 150 C by combining ALD TiO2 and TiN deposition cycles in the PEALD
system. TiO2 is deposited by alternatively introducing TD MAT and plasma 02, while TiN is deposited by using TDMAT and plasma N2. The composition of TiON is controlled by adjusting the subcycle ratio of TiO2 and TiN (2:1, 1:1, 1:2) in order to tailor the electronic conductivity of titanium oxynitride thin film.
The coating of TiON is directly applied on the as-prepared etched metallic silicon.
The morphology and element mapping were observed by using scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX). Images of the scanned surface are illustrated in Figure 7A through 71. In particular Figure 7A illustrates the resultant particles after Ag deposition, Figure 7B illustrates the particles after etching and Figure 7C
illustrates the particles after sonication.
As can be seen from Figure 7a, there shows a homogenous Ag nanoparticles deposition on the surface of Si particles via a galvanic displacement reaction.
The deposited Ag nanoparticles will act as an important role in the following Date Recue/Date Received 2021-04-30
Example 3 PEALD metal oxynitride deposition: In an alternative method, Titanium oxynitride (TiON) is deposited on the as-prepared etched metallic silicon at 150 C by combining ALD TiO2 and TiN deposition cycles in the PEALD
system. TiO2 is deposited by alternatively introducing TD MAT and plasma 02, while TiN is deposited by using TDMAT and plasma N2. The composition of TiON is controlled by adjusting the subcycle ratio of TiO2 and TiN (2:1, 1:1, 1:2) in order to tailor the electronic conductivity of titanium oxynitride thin film.
The coating of TiON is directly applied on the as-prepared etched metallic silicon.
The morphology and element mapping were observed by using scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX). Images of the scanned surface are illustrated in Figure 7A through 71. In particular Figure 7A illustrates the resultant particles after Ag deposition, Figure 7B illustrates the particles after etching and Figure 7C
illustrates the particles after sonication.
As can be seen from Figure 7a, there shows a homogenous Ag nanoparticles deposition on the surface of Si particles via a galvanic displacement reaction.
The deposited Ag nanoparticles will act as an important role in the following Date Recue/Date Received 2021-04-30
-9-chemical reaction process in HF-H202 system. As illustrated in Figures 7b and 7c, an obvious porous structure was observed at the surface of the Si. Figures 7d, 7d-1 and 7d-2 show the elements mapping after etching and the corresponding mapping of Si and Ag, indicating a certain amount of residual Ag existing on the surface. After being treated in concentrated HNO3, as shown in Figures 7e, 7e-1 and 7f there is no Ag signal mapping can be detected any more, meaning that the successful removal of residual Ag.
Finally, the nano porous Si with high purity was obtained as displayed in Figure 71.
Electrochemical measurements of the etched and coated porous metallurgical silicon were performed using two-electrode coin cells assembled in an argon filled glove box. For preparing the working electrode, 60 wt% Etched metallurgical silicon ALD-A1203 active material, 30 wt% Super P conductive agent, and 10 wt% poly(vinylidene fluoride) binder were mixed in N-methy1-2-pyrrolidone to form a slurry which was applied onto a copper foil current collector using doctor-blade technique and then dried under vacuum at 80 C
overnight. After that, the electrode was cut into round disks (<1>=12 mm) for the testing electrode in coin cells. The mass loading was around 2.0 mg on each disk. Electrochemical tests were carried out using CR2032 coin cells assembled in a glove box filled Ar gas with high purity. Li metal foil was used as the counter electrode and polypropylene (PP) (Celgard 2500) as the separator. 1.3 M LiPF6 in a 3:7 ethylene carbonate: diethyl carbonate (EC:
DEC) with 10% fluoroethylene carbonate (FEC) additive were used as electrolyte and each cell was filled with 80 pL electrolyte. The cells were galvanostatically charged and discharged in a voltage window of 0.05-1.0 V
(vs. Li+/Li) at different current densities on a Neware BTS 4000 battery tester.
The charge/discharge specific capacities were calculated based on the mass of active materials. All the electrochemical testing was conducted at room temperature (20 C).
For comparison, a metallurgical silicon powder, which was prepared from metallurgical particles through ball-milling, was also tested as LIB anodes.
Date Recue/Date Received 2021-04-30
Finally, the nano porous Si with high purity was obtained as displayed in Figure 71.
Electrochemical measurements of the etched and coated porous metallurgical silicon were performed using two-electrode coin cells assembled in an argon filled glove box. For preparing the working electrode, 60 wt% Etched metallurgical silicon ALD-A1203 active material, 30 wt% Super P conductive agent, and 10 wt% poly(vinylidene fluoride) binder were mixed in N-methy1-2-pyrrolidone to form a slurry which was applied onto a copper foil current collector using doctor-blade technique and then dried under vacuum at 80 C
overnight. After that, the electrode was cut into round disks (<1>=12 mm) for the testing electrode in coin cells. The mass loading was around 2.0 mg on each disk. Electrochemical tests were carried out using CR2032 coin cells assembled in a glove box filled Ar gas with high purity. Li metal foil was used as the counter electrode and polypropylene (PP) (Celgard 2500) as the separator. 1.3 M LiPF6 in a 3:7 ethylene carbonate: diethyl carbonate (EC:
DEC) with 10% fluoroethylene carbonate (FEC) additive were used as electrolyte and each cell was filled with 80 pL electrolyte. The cells were galvanostatically charged and discharged in a voltage window of 0.05-1.0 V
(vs. Li+/Li) at different current densities on a Neware BTS 4000 battery tester.
The charge/discharge specific capacities were calculated based on the mass of active materials. All the electrochemical testing was conducted at room temperature (20 C).
For comparison, a metallurgical silicon powder, which was prepared from metallurgical particles through ball-milling, was also tested as LIB anodes.
Date Recue/Date Received 2021-04-30
-10-The metallurgical silicon powder, etched metallurgical silicon and etched and coated metallurgical silicon were galvanostatically cycling at 0.3C (1C=2000 mA g-1) in the voltage window of 0.05-1.0 V. As shown in Figure 8A, the metallurgical silicon powder only shows a discharge capacity of less than 20 mAh g-1 for all the cycles, indicating a non-electrochemical activity for the raw metallurgical silicon materials. As expected, the etched metallurgical silicon shows a dramatic capacity increase after the etching which demonstrating the adopted MCE method can have great effectiveness in producing highly-electrochemical active Si. The etched metallurgical silicon delivers an initial discharge and charge capacities of 3036.1 mAh g-1 and 2120.6 mAh g-1, respectively, with a Coulombic efficiency of 69.8%. With additional ALD A1203 coating, the etched and coated metallurgical silicon exhibits an initial discharge capacity of 3099.1 mAh g-1 and a charge capacity of 2265.7 mAh g-1, indicating a Coulombic efficiency 0f73.1 %. The improved efficiency of the etched and coated metallurgical silicon (73.1%) in the first cycle compared to that of the etched metallurgical silicon (69.9%) should be associated with the ALD A1203 coating layer, which decrease side reactions between the Si and electrolyte, and expedites the formation of the stable solid/electrolyte interface (SEI) layer on the surface of Si. Furthermore, Figures 8A and 8C shows clearly that the etched and coated metallurgical silicon displays much better cycling stability and higher capacities than the etched metallurgical silicon.
The discharge capacity of the etched metallurgical silicon changes from 3036.1 mAh g-1 in the initial cycle to 395. 7 mAh g-1 in the 1001h cycle, with only a capacity retention of 13.0% after 100 cycles. In contrast, the etched and coated metallurgical silicon exhibits a discharge capacity of 3099.1 mAh g-1 in the first cycle, and stables at 791.0 mAh g-1, with a higher capacity retention of 25.5%. The results fully demonstrated that ALD A1203 coating can greatly enhance the cycling stability upon cycling. Moreover, when the etched and coated metallurgical silicon was cycling at high rate of 1C (2 A g-1), its discharge capacity stabilizes at 607.5 mAh g-1 after over 1000 cycles, and the Coulombic efficiency stills hold above 99.5% during the whole cycling, indicating a very impressive cycling stability.
Date Recue/Date Received 2021-04-30
The discharge capacity of the etched metallurgical silicon changes from 3036.1 mAh g-1 in the initial cycle to 395. 7 mAh g-1 in the 1001h cycle, with only a capacity retention of 13.0% after 100 cycles. In contrast, the etched and coated metallurgical silicon exhibits a discharge capacity of 3099.1 mAh g-1 in the first cycle, and stables at 791.0 mAh g-1, with a higher capacity retention of 25.5%. The results fully demonstrated that ALD A1203 coating can greatly enhance the cycling stability upon cycling. Moreover, when the etched and coated metallurgical silicon was cycling at high rate of 1C (2 A g-1), its discharge capacity stabilizes at 607.5 mAh g-1 after over 1000 cycles, and the Coulombic efficiency stills hold above 99.5% during the whole cycling, indicating a very impressive cycling stability.
Date Recue/Date Received 2021-04-30
-11-The enhanced electrochemical performance of etched and coated particles could be ascribed to three reasons. Firstly, the nano size of these particles not only shorten the diffusion distance of lithium ions and electrons but also offer higher electrode/electrolyte contact area, benefiting fast kinetic reaction inside the bulk. The enlarged contact area will have negative effect on deteriorating the electrochemical performance if the Si surface is covered with uniform and thin coating layer. Secondly, the nano pores insides the particles can effectively buffer the huge volume changes during the repeated lithiation and delithiation process, thus leading to superior cycling performance with high lithium storage capacity. Lastly, the uniform ALD A1203 coating layer with only about 3 nm thickness can prevent the direct contact between the electrode and electrolyte with suppressed side reactions and create a stable SEI layer at the electrode/electrolyte interface. In particular, The resulting etched and coated metallurgical silicon particles showed enhanced electrochemical cycling stability and superior lithium storage capacity.
While specific embodiments have been described and illustrated, such embodiments should be considered illustrative only and not as limiting the disclosure as construed in accordance with the accompanying claims.
Date Recue/Date Received 2021-04-30
While specific embodiments have been described and illustrated, such embodiments should be considered illustrative only and not as limiting the disclosure as construed in accordance with the accompanying claims.
Date Recue/Date Received 2021-04-30
Claims (20)
1. A method for producing an anode for a battery comprising:
providing a quantity of metallurgical silicon;
etching the metallurgical silicon; and depositing a ceramic layer on the etched metal deposited metallurgical silicon.
providing a quantity of metallurgical silicon;
etching the metallurgical silicon; and depositing a ceramic layer on the etched metal deposited metallurgical silicon.
2. The method of claim 1 further comprising depositing a quantity of a metal on the surface of the quantity of metallurgical silicon to produce a metal deposited metallurgical silicon before etching.
3. The method of claim 2 further comprising reducing the size of the metallurgical silicon into particles having a diameter selected to be between 0.5 and 50 mm.
4. The method of claim 3 wherein the reducing comprises mechanically reducing.
5. The method of claim 4 wherein the mechanical reducing comprises crushing.
6. The method of claim 2 wherein the metal is selected from the group comprising silver, gold, platinum, nickel and iron.
7. The method of claim 6 wherein the metallurgical silicon is immersed in a solution containing a salt of the metal.
8. The method of claim 7 wherein the metal is deposited on to the surface of the metallurgical silicon through a galvanic displacement reaction.
Date Recue/Date Received 2021-04-30
Date Recue/Date Received 2021-04-30
9. The method of claim 1 wherein the ceramic layer comprises a metal oxide.
10. The method of claim 9 wherein the metal oxide is selected from the group consisting of aluminum oxide, titanium oxide, zirconium oxide and silicon oxide.
11. The method of claim 1 wherein the ceramic layer comprises a metal oxynitride.
12. The method of claim 11 wherein the metal oxynitride is selected from the group consisting of aluminium oxynitride, titanium oxynitride and tantalum oxynitride.
13. The method of claim 8 wherein the ceramic layer is selected to have a thickness between 1 and 20 nm.
14. The method of claim 13 wherein the ceramic layer is formed by atomic layer deposition.
15. An anode for a battery comprising at least one particle of porous metallurgical silicon having a ceramic layer formed thereover.
16. The anode of claim 15 wherein the particle of porous metallurgical silicon is formed by metal assisted chemical etching a quantity of metallurgical silicon.
17. The anode of claim 16 wherein the ceramic layer is formed by atomic layer deposition.
18. The anode of claim 17 wherein the ceramic layer is selected to have a thickness of between 1 and 20 nm.
Date Recue/Date Received 2021-04-30
Date Recue/Date Received 2021-04-30
19. The anode of claim 15 wherein a plurality of particles of porous metallurgical silicon are secured in a binder.
20. A lithium ion battery comprising:
a cathode;
an anode comprising at least one particle of porous metallurgical silicon having a ceramic layer formed thereover; and a non-aqueous lithium containing electrolyte between the cathode and anode.
Date Recue/Date Received 2021-04-30
a cathode;
an anode comprising at least one particle of porous metallurgical silicon having a ceramic layer formed thereover; and a non-aqueous lithium containing electrolyte between the cathode and anode.
Date Recue/Date Received 2021-04-30
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