Electrode architecture for fast charging

Abstract

The present invention provides an electrode for an electrochemical cell. The electrode includes a carbon film having a first side and an opposing second side, wherein at least a portion of the carbon film is modified to include an increased number of lithium nucleation sites relative to the unmodified carbon film.

Description

Technical Field

[0001] This section provides background information related to the present disclosure which is not necessarily prior art.

[0002] Electrochemical energy storage devices, such as lithium-ion batteries, can be used in a variety of products, including automotive products such as start-stop systems (e.g., 12 V start-stop systems), battery-assisted systems ("µBAS"), hybrid electric vehicles ("HEV"), and electric vehicles ("EV"). Lithium-ion batteries generally include two electrodes, a separator, and an electrolyte. One of the two electrodes serves as a positive electrode or cathode, and the other electrode serves as a negative electrode or anode. Lithium-ion batteries may also include various terminals and packaging materials. Many rechargeable lithium-ion batteries operate by reversibly transferring lithium ions back and forth between a negative electrode and a positive electrode. For example, lithium ions can move from a positive electrode to a negative electrode during battery charging, and move in the opposite direction when the battery is discharged. Background Art

[0003] During cycling of lithium-ion batteries, lithium is plated on and stripped from the anode. It would therefore be beneficial to provide anode materials that do not exhibit significant volume changes during cycling and that resist dendrite formation. Summary of the invention

[0004] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0005] The present disclosure relates to electrode architectures for fast charging.

[0006] In various aspects, the present technology provides an electrode including a carbon film having a first side and an opposing second side, wherein at least a portion of the carbon film is modified to include an increased number of lithium nucleation sites relative to the unmodified carbon film.

[0007] In one aspect, the carbon film comprises carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof.

[0008] In one aspect, substantially all of the carbon film is modified, and the carbon film defines an electrode and a current collector.

[0009] In one aspect, the carbon film is substantially free of molecules covalently bonded to the carbon film.

[0010] In one aspect, a portion of at least one of the first side or the opposing second side of the carbon film is physically modified, and at least a central portion of the carbon film is unmodified and defines a current collector.

[0011] In one aspect, the carbon film is substantially free of molecules covalently bonded to the carbon film.

[0012] In one aspect, at least one of the first side or the second side is modified by a lithophilic layer and a central portion of the carbon film is unmodified and defines a current collector.

[0013] In one aspect, the lithophilic layer includes silver (Ag), gold (Au), aluminum (Al), silicon (Si), tin (Sn), alone or in combination.

[0014] In one aspect, at least one of the first face or the second face is modified with a dopant and a central portion of the carbon film is unmodified and defines a current collector.

[0015] In one aspect, the dopant includes nitrogen (N), sulfur (S), phosphorus (P), boron (B), or combinations thereof.

[0016] In one aspect, the electrode is an anode.

[0017] In various aspects, the present technology also provides an electrochemical cell for cycling lithium ions, the electrochemical cell comprising an electrode.

[0018] In various aspects, the present technology also provides an electrode for an electrochemical cell, the electrode comprising a carbon material having a first face and an opposing second face, the carbon material comprising carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof, wherein at least a portion of the carbon material is modified to include an increased number of lithium nucleation sites relative to the unmodified carbon material, and wherein the electrode exhibits a state of charge (SOC) greater than or equal to about 75% after charging for 15 minutes.

[0019] In one aspect, the electrode also exhibits a volume change of less than or equal to about 20% during lithium plating and stripping.

[0020] In various aspects, the present technology also provides a method for manufacturing an electrode, which includes obtaining a carbon material having a first side and an opposite second side, the carbon material including carbon nanotubes, carbon nanofibers, carbon paper, graphene paper or a combination thereof, and modifying at least one side of the carbon material to generate a modified carbon material, the modified carbon material including an increased number of lithium nucleation sites relative to the unmodified carbon material.

[0021] In one aspect, the modification comprises modifying substantially all of the carbon material by laser ablation, oxygen plasma, wet chemical oxidation, or a combination thereof, such that the modified carbon material defines the entire electrode.

[0022] In one aspect, the modifying comprises modifying at least one of the first face or the second face by laser ablation, oxygen plasma, wet chemical oxidation, or a combination thereof, and not modifying a central portion of the carbon material between the first face and the second face.

[0023] In one aspect, the modifying includes disposing a lithophilic layer on at least one of the first face or the second face, and not modifying a central portion of the carbon material between the first face and the second face, wherein the disposing is performed by electrochemical plating or vapor deposition.

[0024] In one aspect, the modification comprises doping at least one of the first face or the second face, and a central portion of the carbon material between the first face and the second face is not modified, wherein the doping comprises doping with nitrogen by contact with a nitrogen-generated or ammonia-generated plasma, doping with sulfur by heat treatment with phenyl disulfide, doping with phosphorus by heat treatment with pentaphenylphosphoryl oxide, or doping with boron by heat treatment with boric acid.

[0025] In one aspect, the method further comprises incorporating lithium into the modified carbon material by vacuum infiltration, electrochemical plating, thermal evaporation, lithium foil lamination, or a combination thereof.

[0026] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0027] The present disclosure also includes the following technical solutions.

[0028] Technical Solution 1. An electrode for an electrochemical cell, the electrode comprising:

[0029] a carbon film having a first side and an opposing second side,

[0030] wherein at least a portion of the carbon film is modified to include an increased number of lithium nucleation sites relative to an unmodified carbon film.

[0031] Technical Solution 2. An electrode according to Technical Solution 1, wherein the carbon film comprises carbon nanotubes, carbon nanofibers, carbon paper, graphene paper or a combination thereof.

[0032] Technical Solution 3. The electrode according to Technical Solution 1, wherein substantially all of the carbon film is modified, and the carbon film defines the electrode and the current collector.

[0033] Technical Solution 4. An electrode according to Technical Solution 3, wherein the carbon film substantially does not contain molecules covalently bonded to the carbon film.

[0034] Technical Solution 5. An electrode according to Technical Solution 1, wherein a portion of at least one of the first face or the opposing second face of the carbon film is physically modified, and wherein at least a central portion of the carbon film is unmodified and defines a current collector.

[0035] Technical Solution 6. An electrode according to Technical Solution 5, wherein the carbon film substantially does not contain molecules covalently bonded to the carbon film.

[0036] Technical Solution 7. The electrode according to Technical Solution 1, wherein at least one of the first face or the second face is modified by a lithophilic layer, and wherein a central portion of the carbon film is not modified and defines a current collector.

[0037] Technical Solution 8. The electrode according to Technical Solution 7, wherein the lithophilic layer contains silver (Ag), gold (Au), aluminum (Al), silicon (Si), tin (Sn) or a combination thereof.

[0038] Technical Solution 9. The electrode according to Technical Solution 1, wherein at least one of the first face or the second face is modified by a dopant, and wherein a central portion of the carbon film is not modified and defines a current collector.

[0039] Technical Solution 10. An electrode according to Technical Solution 9, wherein the dopant comprises nitrogen (N), sulfur (S), phosphorus (P), boron (B) or a combination thereof.

[0040] Technical Solution 11. An electrode according to Technical Solution 1, wherein the electrode is an anode.

[0041] Technical Solution 12. A circulating lithium ion electrochemical cell, the electrochemical cell comprising the electrode according to Technical Solution 1.

[0042] Technical Solution 13. An electrode for an electrochemical cell, the electrode comprising:

[0043] A carbon material having a first side and an opposite second side, the carbon material comprising carbon nanotubes, carbon nanofibers, carbon paper, graphene paper or a combination thereof,

[0044] wherein at least a portion of the carbon material is modified to include an increased number of lithium nucleation sites relative to the unmodified carbon material, and

[0045] The electrode exhibits a state of charge (SOC) greater than or equal to about 75% after charging for 15 minutes.

[0046] Technical Solution 14. An electrode according to Technical Solution 13, wherein the electrode also exhibits a volume change of less than or equal to about 20% during lithium plating and stripping.

[0047] Technical Solution 15. A method for manufacturing an electrode, the method comprising:

[0048] obtaining a carbon material having a first side and an opposite second side, the carbon material comprising carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof; and

[0049] At least one face of the carbon material is modified to produce a modified carbon material comprising an increased number of lithium nucleation sites relative to the unmodified carbon material.

[0050] Technical Solution 16. The method according to Technical Solution 15, wherein the modification comprises modifying substantially all of the carbon material by laser ablation, oxygen plasma, wet chemical oxidation, or a combination thereof, so that the modified carbon material defines the entire electrode.

[0051] Technical Solution 17. A method according to Technical Solution 15, wherein the modification comprises modifying at least one of the first surface or the second surface by laser ablation, oxygen plasma, wet chemical oxidation or a combination thereof, and does not modify the central portion of the carbon material between the first surface and the second surface.

[0052] Technical Solution 18. A method according to Technical Solution 15, wherein the modification comprises setting a lithophilic layer on at least one of the first surface or the second surface, and not modifying a central portion of the carbon material between the first surface and the second surface, wherein the setting is performed by electrochemical plating or vapor deposition.

[0053] Technical Solution 19. A method according to Technical Solution 15, wherein the modification comprises doping at least one of the first surface or the second surface, and does not modify the central portion of the carbon material between the first surface and the second surface, wherein the doping comprises: doping nitrogen by contact with nitrogen-generated or ammonia-generated plasma, doping sulfur by heat treatment with phenyl disulfide, doping phosphorus by heat treatment with pentaphenylphosphoryl oxide, or doping boron by heat treatment with boric acid.

[0054] Technical Solution 20. The method according to Technical Solution 15 further comprises:

[0055] Lithium is incorporated into the modified carbon material by vacuum infiltration, electrochemical plating, thermal evaporation, lithium foil lamination, or a combination thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0057] Figure 1 is a schematic diagram of a lithium-ion battery in accordance with various aspects of the present technology.

[0058] Figure 2is a schematic diagram of a lithium-ion battery in accordance with various aspects of the present technology.

[0059] Figure 3 is a schematic diagram showing a comparative electrode undergoing volume change during cycling.

[0060] Figure 4 Schematic diagram showing a cross section of a first electrode according to various aspects of the present technology.

[0061] Figure 5 Schematic diagram showing a cross section of a second electrode according to various aspects of the present technology.

[0062] Figure 6 Schematic diagram showing a cross section of a third electrode according to various aspects of the present technology.

[0063] Figure 7 Schematic diagram showing a cross section of a fourth electrode according to various aspects of the present technology.

[0064] Fig. 8A is a micrograph showing the surface of a film including carbon nanotubes and carbon nanofibers. The scale bar is 30 μm.

[0065] Figure 8B yes Fig. 8A Magnified micrograph of the surface of the membrane shown in. Scale bar is 6 μm.

[0066] Figure 8C It is shown FIG. 8A to FIG. 8B Micrograph of a cross section of the membrane shown in. Scale bar 100 μm.

[0067] Fig. 9 is a micrograph showing the surface of an exemplary membrane including carbon nanotubes and carbon nanofibers, wherein the surface is modified according to various aspects of the present technology. The scale bar is 6 μm.

[0068] Fig.10 is a Nyquist plot showing the impedance of an exemplary electrode prepared according to various aspects of the present technology.

[0069] Fig.11 is a graph showing the state of charge (SOC) of an electrode including unmodified carbon nanotubes and carbon nanofibers. The solid line corresponds to the lithium metal electrode control, while the dashed line corresponds to the unmodified electrode.

[0070] Fig.12 is a graph showing the state of charge (SOC) of an exemplary electrode including modified carbon nanotubes and carbon nanofibers according to various aspects of the present technology. The solid line corresponds to the lithium metal electrode control, while the dashed line corresponds to the modified electrode.

[0071] Fig.13is a graph illustrating the stability of exemplary electrodes including modified carbon nanotubes and carbon nanofibers according to various aspects of the present technology.

[0072] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0073] Exemplary embodiments are provided so that the present disclosure will be thorough and will fully convey the scope to those skilled in the art. Many specific details, such as examples of specific compositions, components, devices, and methods, are set forth to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, and that exemplary embodiments may be implemented in many different forms, and none of them should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known techniques are not described in detail.

[0074] The terms used herein are only for the purpose of describing specific exemplary embodiments, and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" may also be intended to include plural forms. The terms "comprises / comprising", "including", and "having" are inclusive, thus specifying the presence of stated features, elements, compositions, steps, integers, operations, and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or combinations thereof. Although the open term "comprising" should be understood as a non-binding term for describing and claiming the various embodiments set forth herein, in some respects, the term is alternatively understood as a more restrictive and binding term, such as "consisting of" or "consisting essentially of". Thus, for any given embodiment that recites a composition, material, component, element, feature, integral body, operation, and / or process step, the present disclosure also specifically includes embodiments consisting of or consisting essentially of the composition, material, component, element, feature, integral body, operation, and / or process step so recited. In the case of "consisting of," alternative embodiments exclude any additional composition, material, component, element, feature, integral body, operation, and / or process step, while in the case of "consisting essentially of," any additional composition, material, component, element, feature, integral body, operation, and / or process step that substantially affects the basic and novel characteristics is excluded from such embodiment, but any composition, material, component, element, feature, integral body, operation, and / or process step that does not substantially affect the basic and novel characteristics may be included in the embodiment.

[0075] Any method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless expressly identified as an order of performance. It should also be understood that additional or alternative steps may be employed unless otherwise indicated.

[0076] When a part, element or layer is referred to as being "on another element or layer," "engaged to," "connected to," or "coupled to" another element or layer, it may be directly on, engaged to, connected to, or coupled to another part, element or layer, or there may be intermediate elements or layers. In contrast, when an element is referred to as being "directly on another element or layer," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intermediate elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0077] Although the terms first, second, third, etc. can be used to describe various steps, elements, components, regions, layers and / or sections in this article, unless otherwise specified, these steps, elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish a step, element, component, region, layer or section from another step, element, component, region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in this article. Therefore, without departing from the teaching of exemplary embodiments, the first step, element, component, region, layer or section discussed below can be referred to as the second step, element, component, region, layer or section.

[0078] For ease of description, spatially or temporally relative terms, such as "before," "after," "inner," "outer," "beneath," "below," "lower," "above," "upper," etc., may be used herein to describe the relationship of one element or feature to another element(s) or feature(s) shown in the drawings. Spatially or temporally relative terms may also be intended to encompass different orientations of a device or system in use or operation in addition to the orientations depicted in the drawings.

[0079] Throughout this disclosure, numerical values ​​represent approximate measures or limits of ranges to cover minor deviations from given values ​​and embodiments having approximately mentioned values ​​as well as having exactly mentioned values. In addition to the working examples provided at the end of the detailed description, in this specification, the numerical values ​​of all parameters (e.g., quantities or conditions), including the appended claims, should be understood as being modified by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. "About" indicates that the stated numerical value allows some slight imprecision (a bit close to exact in value; close to or quite close to the value; almost). If the imprecision provided by "approximately" is not understood in the art to have such ordinary meaning, the "about" used herein at least represents the variation that can be produced by the ordinary methods of measuring and using such parameters. For example, "about" may include less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some aspects, optionally less than or equal to 0.1%.

[0080] Additionally, the disclosure of ranges includes disclosure of all values ​​and further divided ranges within the entire range, including the endpoints and sub-ranges given for that range.

[0081] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0082] Lithium metal electrodes expand and contract during lithium-ion electrode cycling. These volume changes can lead to mossy surface structures, low cycle efficiency, dendrite growth, and high overpotentials. Therefore, the present technology provides an electrode with a high surface area that, when used as an anode in a lithium-ion battery, prevents dendrite formation, reduces current density, and improves cycle life.

[0083] Figure 1 An exemplary schematic diagram of an electrochemical cell 20 (also referred to herein as a "battery") that circulates lithium ions, i.e., a lithium ion battery, is shown. Unless otherwise expressly indicated, the term "ion" as used herein means lithium ions. The battery 20 includes a negative electrode (i.e., an anode) 22, a positive electrode (i.e., a cathode) 24, and a separator 30 (e.g., a microporous polymer separator) disposed between the two electrodes 22, 24. The electrolyte is present in the form of a liquid or gel throughout the separator 30, and is optionally present in the negative electrode 22 and the positive electrode 24. A plurality of first solid electrolyte particles (i.e., an anode electrolyte 90) may be bonded to the nucleation site of the negative electrode 22, and a plurality of second solid electrolyte particles (i.e., a cathode electrolyte 92) may be mixed with positive electroactive particles 60 present in the positive electrode 24, which may be positive solid electroactive particles, to form a continuous electrolyte network.

[0084] Negative electrode current collector 32 is located within negative electrode 22 and is in electrical communication with negative electrode 22. Positive electrode current collector 34 may be located at or near positive electrode 24 and is in electrical communication with negative electrode 24. Negative electrode current collector 32 and positive electrode current collector 34 collect and move free electrons into and out of external circuit 40, respectively (as indicated by the box arrows). For example, external circuit 40 may be interrupted and load device 42 may connect negative electrode 22 (through negative electrode current collector 32) and positive electrode 24 (through positive electrode current collector 34). The composite electrode may also include a conductive diluent, such as carbon black or carbon nanotubes, dispersed throughout the material defining positive electrode 24.

[0085] The battery 20 can generate an electric current (indicated by a box arrow) during discharge through a reversible electrochemical reaction, which occurs when the external circuit 40 is closed (to connect the negative electrode 22 and the positive electrode 24), and when the negative electrode 22 contains a relatively large amount of lithium. The chemical potential difference between the negative electrode 22 and the positive electrode 24 drives electrons generated by the oxidation of the lithium inserted at the negative electrode 22 to the positive electrode 24 through the external circuit 40. Ions also generated at the negative electrode 22 are transferred to the positive electrode 24 through the electrolyte and the separator 30. The electrons flow through the external circuit 40, and the ions migrate across the separator 30 to the positive electrode 24, where they can be plated, reacted, or intercalated. The current through the external circuit 40 can be used and passed through the load device 42 (in the direction of the box arrow) until the lithium in the negative electrode 22 is exhausted and the capacity of the battery 20 is reduced.

[0086] The battery 20 can be charged or recharged at any time by connecting an external power source (e.g., a charging device) to the battery 20 to reverse the electrochemical reaction that occurs during battery discharge. The connection of the external power source to the battery 20 forces the non-spontaneous oxidation of one or more metal elements at the positive electrode 24 to generate electrons and ions. The electrons flowing back to the negative electrode 22 through the external circuit 40 and the ions flowing back to the negative electrode 22 through the separator 30 are re-polymerized at the negative electrode 22 and replenish lithium for consumption in the next battery discharge cycle. In this way, each discharge and charge event is considered to be a cycle in which ions circulate between the positive electrode 24 and the negative electrode 22.

[0087] The external power source that can be used to charge the battery 20 may vary depending on the size, construction, and specific end use of the battery 20. Some notable and exemplary external power sources include, but are not limited to, AC power sources such as AC wall outlets and motor vehicle alternators, which may require the use of an AC:DC converter. In many configurations of the battery 20, each of the negative electrode collector 32, the negative electrode 22, the separator 30, the positive electrode 24, and the positive electrode collector 34 is prepared as a relatively thin layer (e.g., a thickness of from a few microns to a millimeter or less) and assembled into layers connected in an electrically parallel arrangement to provide suitable electrical energy and power packaging. In various other cases, the battery 20 may include electrodes 22, 24 connected in series.

[0088] In addition, in some aspects, the battery 20 may include various other components known to those skilled in the art, although not shown here. For example, as a non-limiting example, the battery 20 may include a housing, a gasket, a terminal cap, and any other conventional components or materials that may be located within the battery 20, including between or around the negative electrode 22, the positive electrode 24, and / or the separator 30. As described above, the size and shape of the battery 20 may vary depending on the specific application for which it is designed. Battery-powered vehicles and handheld consumer electronic devices are two examples of where the battery 20 is most likely to be designed with different sizes, capacities, and power output specifications. If the load device 42 requires, the battery 20 may also be connected in series or in parallel with other similar lithium-ion cells or batteries to produce greater voltage output, energy, and power.

[0089] Thus, the battery 20 can generate current to a load device 42 that is operably connected to the external circuit 40. When the battery 20 is discharged, the load device 42 can be fully or partially powered by the current flowing through the external circuit 40. Although the load device 42 can be any number of known electric devices, some specific examples of energy-consuming load devices include, as non-limiting examples, electric motors for hybrid or all-electric vehicles, laptop computers, tablet computers, cellular phones, and cordless power tools or appliances. The load device 42 can also be a power generation device that charges the battery 20 to store energy.

[0090] The separator 30 is disposed between the negative electrode 22 and the positive electrode 24. The separator 30 works as an electrical insulator by being sandwiched between the negative electrode 22 and the positive electrode 24 to prevent physical contact and short circuiting. A liquid electrolyte solution is present throughout the separator 30 and is optionally present in the negative electrode 22 as an anode electrolyte 90 and / or in the positive electrode 24 as a cathode electrolyte 92. Therefore, in addition to providing a physical barrier between the electrodes 22, 24, the separator 30 also acts like a sponge, containing the electrolyte solution in an open pore network during lithium ion cycling to facilitate the function of the battery 20. As described above, the chemical potential difference between the positive electrode 24 and the negative electrode 22 drives electrons generated by oxidation of lithium embedded at the negative electrode 22 to the positive electrode 24 through the external circuit 40. Lithium ions also generated at the negative electrode 22 are simultaneously transferred to the positive electrode 24 through the liquid electrolyte solution contained in the separator 30. The electrons flow through the external circuit 40 , and the lithium ions migrate across the separator 30 containing the electrolyte solution, thereby forming intercalated lithium at the positive electrode 24 .

[0091] Separator 30 is used as both an electrical insulator and a mechanical support. In some aspects, separator 30 comprises a polyolefin, which may be microporous. Polyolefins may be homopolymers (derived from a single monomer component) or heteropolymers (derived from more than one monomer component), which may be linear or branched. If the heteropolymer is derived from two monomer components, the polyolefin may adopt any copolymer chain arrangement, including block copolymers or random copolymers. Similarly, if the polyolefin is a heteropolymer derived from more than two monomer components, it may also be a block copolymer or a random copolymer. In some aspects, the polyolefin may be polyethylene (PE), polypropylene (PP) or a blend of polyethylene (PE) and polypropylene (PP).

[0092] When the separator 30 is a microporous polymer separator, it can be a single layer or multilayer laminate, which can be manufactured by a dry or wet process. For example, in one embodiment, a single layer of polyolefin can form the entire microporous polymer separator 30. In other aspects, the separator 30 can be a fiber membrane with a large number of holes extending between the relative surfaces, and can have a thickness of, for example, less than 1 mm. As another example, multiple discrete layers of similar or dissimilar polyolefins can be assembled to form the microporous polymer separator 30. Polyolefins can be homopolymers (derived from a single monomer component) or heteropolymers (derived from more than one monomer component), which can be linear or branched. If the heteropolymer is derived from two monomer components, the polyolefin can be arranged in any copolymer chain, including block copolymers or random copolymers. Similarly, if the polyolefin is a heteropolymer derived from more than two monomer components, it can also be a block copolymer or a random copolymer. In certain aspects, the polyolefin may be polyethylene (PE), polypropylene (PP), a blend of polyethylene (PE) and polypropylene (PP), or a multilayer structured porous film of polyethylene (PE) and / or polypropylene (PP). In addition to polyolefins, the microporous polymer separator 30 may also include other polymers such as, but not limited to, polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), and / or polyamide. Commercially available polyolefin porous membranes include CELGARD ® 2500 (single-layer polypropylene divider) and CELGARD ® 2320 (three-layer polypropylene / polyethylene / polypropylene separator), both available from Celgard LLC. The polyolefin layer and any other optional polymer layers may also be included as fiber layers in the microporous polymer separator 30 to help give the microporous polymer separator 30 the appropriate structural and porosity properties. A variety of conventionally available polymers and commercial products for forming the separator 30 are contemplated, as well as many manufacturing methods that can be used to produce such microporous polymer separators 30.

[0093] When a polymer is used, the separator 30 may be mixed with a ceramic material or its surface may be coated in a ceramic material. For example, the ceramic coating may include a ceramic oxide such as aluminum oxide (Al 2 O 3 ), silicon dioxide (SiO 2 ), titanium dioxide (TiO 2), lithium lanthanum zirconium oxide (LLZO), lithium lanthanum titanium oxide (LLTO), lithium aluminum titanium phosphate (LATP), lithium super ion conductor (LISICON), lithium phosphorus oxynitride (LIPON), or a combination thereof. In various alternative embodiments, instead of a polymeric material as described above, separator 30 comprises a green ceramic oxide (i.e., a ceramic oxide that has not been sintered or otherwise densified) having a high porosity of greater than or equal to about 10% by volume to less than or equal to about 50% by volume.

[0094] Any suitable liquid electrolyte solution capable of conducting lithium ions between negative electrode 22 and positive electrode 24 may be used in battery 20. In certain aspects, the electrolyte solution may be a non-aqueous liquid electrolyte solution comprising a lithium salt dissolved in an organic solvent or a mixture of organic solvents. Many conventional non-aqueous liquid electrolyte solutions may be used in battery 20. A non-limiting list of salts that may be dissolved in an organic solvent to form a non-aqueous liquid electrolyte solution includes: lithium hexafluorophosphate (LiPF 6 )、Lithium bis(fluorosulfonyl)imide (LiFSi), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium tetrafluoroborate (LiBF 4 ), lithium bis(oxalate)borate (LiBOB), lithium oxalyldifluoroborate (LiODFB), lithium sulfonylbis(fluorosulfonyl)imide (LiSFSI), lithium carbonylbis(fluorosulfonyl)imide (LiCFSI), lithium perchlorate (LiClO 4 ), lithium tetrachloroaluminate (LiAlCl 4 )、lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetraphenylborate (LiB(C 6 H 5 ) 4 ) and lithium hexafluoroarsenate (LiAsF 6 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 )、Lithium Bis(trifluoromethanesulfonimide)(LiN(CF 3 SO 2 ) 2) and combinations thereof. These and other similar salts can be dissolved in various organic solvents, including, but not limited to, various alkyl carbonates, such as: cyclic carbonates (propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), fluorinated cyclic carbonates (fluorinated ethylene carbonate (FEC)), acyclic carbonates (dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC)), fatty carboxylic acid esters (methyl formate, methyl acetate, methyl propionate), γ-lactones (γ-butyrolactone, γ-valerolactone), chain structure ethers (1,2-dimethoxyethane, 1-2-diethoxyethane, ethoxymethoxyethane, ethyl propyl ether (EPE), fluorinated linear carbonates (F-EMC), fluorinated ethers (F-EPE)), cyclic ethers (tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF)) and mixtures thereof.

[0095] refer to Figure 2 , the present technology also considers solid-state batteries that cycle lithium ions21. Figure 1 Components of the solid-state battery 21 that have equivalent corresponding components in the battery 20 are marked with the same numbers. Thus, the solid-state battery 21 includes a negative electrode 22, a negative electrode collector 32, a positive electrode 24, and a positive electrode collector 34. However, the solid-state battery 21 does not include a porous separator 30 and a liquid electrolyte solution. Therefore, in addition to the above description of the separator 30 and the liquid electrolyte solution, the description of the battery 20 is also applicable to the solid-state battery 21.

[0096] Instead of a separator and a liquid electrolyte solution, the solid-state battery 21 includes a solid electrolyte 36 that provides electrical separation between the negative electrode 22 (i.e., the anode) and the positive electrode 24 (i.e., the cathode) - preventing physical contact. The solid electrolyte 36 also provides a path of least resistance for the internal passage of ions. In various aspects, a plurality of first solid electrolyte particles 38 may define the solid electrolyte 36. For example, the solid electrolyte 36 may be in the form of a layer or composite including a plurality of first solid electrolyte particles 38. The solid electrolyte 36 may be in the form of a layer having a thickness greater than or equal to about 1 μm to less than or equal to about 1 mm, and in certain aspects, as an example, optionally greater than or equal to about 1 μm to less than or equal to about 100 μm. The solid-state battery 21 circulates lithium ions and electrons in the same manner as the battery 20 described above; however, the lithium ions travel through the solid electrolyte 36 instead of the separator 30 and the liquid electrolyte solution.

[0097] The solid electrolyte particles 38 may include one or more polymer-based particles, oxide-based particles, sulfide-based particles, halide-based particles, borate-based particles, nitride-based particles, and hydride-based particles. Such solid electrolyte particles 38 may be arranged in multiple layers to define a three-dimensional structure. In various aspects, polymer-based particles may be mixed with lithium salts, as described above, thereby acting as a solid solvent. In certain variations, polymer-based particles may include one or more polymer materials selected from the group consisting of: polyethylene glycol, polyparaphenylene oxide (PPO), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), polyvinyl chloride (PVC) and combinations thereof.

[0098] The oxide-based particles may comprise one or more garnet ceramics, LISICON-type oxides, and perovskite-type ceramics. For example, the one or more garnet ceramics may be selected from the group consisting of: Li 6.5 La 3 Zr 1.75 Te 0.25 O 12 , Li 7 La 3 Zr 2 O 12 , Li 6.2 Ga 0.3 La 2.95 R 0.05 Zr 2 O 12 , Li 6.85 La 2.9 Ca 0.1 Zr 1.75 Nb 0.25 O 12 , Li 6.25 Al 0.25 La 3 Zr 2 O 12 , Li 6.75 La 3 Zr 1.75 Nb 0.25 O 12 , Li 6.75 La 3 Zr 1.75 Nb 0.25 O 12 And combinations thereof. The one or more LISICON-type oxides may be selected from the group consisting of: Li 14 Zn(GeO 4 ) 4 , Li3+x (P 1−x Si x ) 4 (where 0 < x <1), Li 3+x Ge x V 1-x O 4 (where 0 < x < 1) and combinations thereof. The one or more perovskite ceramics may be selected from the group consisting of: Li 3.3 La 0.53 TiO 3 、LiSr 1.65 Zr 1.3 Ta 1.7 O 9 , Li 2x-y Sr 1-x Ta y Zr 1-y O 3 (where x = 0.75y and 0.60 <y < 0.75)、Li 3 / 8 Sr 7 / 16 Nb 3 / 4 Zr 1 / 4 O 3 , Li 3x La (2 / 3-x) TiO 3 (where 0 < x < 0.25) and their combinations.

[0099] The sulfide-based particles may include one or more sulfide-based materials selected from the group consisting of: Li 2 SP 2 S 5 , Li 2 SP 2 S 5 -MS x (where M is Si, Ge and Sn, and 0≤x≤2), Li 3.4 Si 0.4 P 0.6 S 4 , Li 10 G 2 S 11.7 O 0.3 , Li 9.6 P 3 S 12 , Li 7 P 3 S 11 , Li 9 P 3 S 9 O 3 , Li 10.35 Si1.35 P 1.65 S 12 , Li 9.81 Sn 0.81 P 2.19 S 12 , Li 10 (Si 0.5 Ge 0.5 ) 2 S 12 、Li(Ge 0.5 Sn 0.5 ) 2 S 12 、Li(Si 0.5 Sn 0.5 ) s S 12 , Li 10 G 2 S 12 (LGPS), Li 6 PS 5 X (wherein X is Cl, Br or I), Li 7 P 2 S 8 I. Li 10.35 Ge 1.35 P 1.65 S 12 , Li 3.25 Ge 0.25 P 0.75 S 4 , Li 10 SnP 2 S 12 , Li 10 SiP 2 S 12 , Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 、(1-x)P 2 S 5 -xLi 2 S (where 0.5≤x≤0.7) and their combinations.

[0100] The halide-based particles may include one or more halide-based particles selected from the group consisting of: Li 2 CdCl 4 , Li 2 MgCl 4 , Li 2 CdI 4 , Li 2 ZnI 4 , Li3 OCl, LiI, Li 5 ZnI 4 , Li 3 OCl 1-x Br x (where 0 < x < 1) and their combinations.

[0101] The borate-based particles may include one or more borate-based materials selected from the group consisting of: Li 2 B 4 O 7 , Li 2 O-(B 2 O 3 )-(P 2 O 5 ) and combinations thereof. In one variation, the one or more borate-based materials may have a value greater than or equal to about 10 -7 S / cm to less than or equal to about 10 -6 S / cm ionic conductivity.

[0102] The nitride-based particles may include one or more nitride-based materials selected from the group consisting of: Li 3 N.Li 7 PN 4 、LiSi 2 N 3 , LiPON, and combinations thereof. In one variation, one or more nitride-based materials may have a thickness greater than or equal to about 10 -9 S / cm to less than or equal to about 10 -3 S / cm ionic conductivity.

[0103] The hydride-based particles may include one or more hydride-based materials selected from the group consisting of: Li 3 AlH 6 , LiBH 4 , LiBH 4 -LiX (wherein X is one of Cl, Br and I), LiNH 2 , Li 2 NH, LiBH 4 -LiNH 2 In one variation, one or more hydride-based materials may have a value greater than or equal to about 10 -7 S / cm to less than or equal to about 10 -4 S / cm ionic conductivity.

[0104] Unless otherwise stated, the following description will further refer to Figure 1However, it should be understood that the following description also applies to Figure 2 The solid-state battery shown.

[0105] The positive electrode 24 may be formed of a lithium-based or electroactive material that can perform lithium intercalation and deintercalation while serving as a positive terminal for the battery 20. For example, in some variations, the positive electrode 24 may be defined by a plurality of positive electroactive particles 60. In some cases, as shown, the positive electrode 24 is a composite of a mixture comprising positive electroactive particles 60 and a cathode electrolyte 92 (e.g., cathode electrolyte particles). For example, the positive electrode 24 may include greater than or equal to about 10% by weight to less than or equal to about 95% by weight, and in some aspects, optionally greater than or equal to about 50% by weight to less than or equal to about 90% by weight of the positive electroactive particles 60, and greater than or equal to about 5% by weight to less than or equal to about 70% by weight, and in some aspects, optionally greater than or equal to about 10% by weight to less than or equal to about 30% by weight of the cathode electrolyte 92. In various cases, the cathode electrolyte 92 may be the same or different from the anode electrolyte 90 or the solid electrolyte particles 38.

[0106] In various aspects, the positive electrode 24 can be one of a layered oxide cathode, a spinel cathode, and a polyanion cathode. For example, in the case of a layered oxide cathode (e.g., a rock salt layered oxide), the positive electrode electroactive particles 60 can include one or more positive electrode electroactive materials selected from LiCoO for lithium ion batteries. 2 、LiNi x Mn y Co 1-x-y O 2 (where 0≤x≤1 and 0≤y≤1), LiNi x Mn 1-x O 2 (0≤x≤1) and Li 1+x MO 2 (0≤x≤1). The spinel cathode may include one or more positive electroactive materials, such as LiMn 2 O 4 and LiNi x Mn 1.5 O 4 The polyanion cathode may include, for example, a phosphate such as LiFePO 4 、LiVPO 4 ,LiV 2 (PO 4 ) 3 , Li 2 FePO 4 F. Li 3 Fe3 (PO 4 ) 4 or Li 3 V 2 (PO 4 )F 3 , and / or silicates, such as LiFeSiO 4 In this manner, in various aspects, the positive electroactive particles 60 may include one or more positive electroactive materials selected from the group consisting of: LiCoO 2 、LiNi x Mn y Co 1-x- y O 2 (where 0≤x≤1 and 0≤y≤1), LiNi x Mn 1-x O 2 (where 0≤x≤1), Li 1+x MO 2 (where 0≤x≤1), LiMn 2 O 4 、LiNi x Mn 1.5 O 4 、LiFePO 4 、LiVPO 4 , LiV 2 (PO 4 ) 3 , Li 2 FePO 4 F. Li 3 Fe 3 (PO 4 ) 4 , Li 3 V 2 (PO 4 )F 3 、LiFeSiO 4 In some aspects, the positively electroactive particles 60 may be coated (e.g., by Al 2 O 3 ) and / or the positive electroactive material may be doped (eg, with magnesium).

[0107] In certain variations, the positively electroactive particles 60 can be optionally mixed with one or more conductive materials that provide an electron conduction path and / or with at least one polymer binder material that improves the structural integrity of the positive electrode 24. For example, the positively electroactive particles 60 can be optionally mixed with a binder, such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene propylene diene monomer (EPDM) rubber, nitrile rubber (NBR), styrene butadiene rubber (SBR) and / or lithium polyacrylate (LiPAA) binder. The conductive material may include, for example, a carbon-based material, powdered nickel or other metal particles, or a conductive polymer. The carbon-based material may include, for example, graphite particles, acetylene black (e.g., KETCHEN ™ Black or DENKA ™ Black), carbon fiber and nanotubes, graphene, etc. Examples of conductive polymers may include polyaniline, polythiophene, polyacetylene, polypyrrole, etc.

[0108] In some aspects, a mixture of conductive materials can be used. For example, the positive electrode 24 can include greater than or equal to about 0% weight fraction to less than or equal to about 25% weight fraction, optionally greater than or equal to about 0% weight fraction to less than or equal to about 10% weight fraction, and in some aspects, optionally greater than or equal to about 0% weight fraction to less than or equal to about 5% weight fraction of one or more conductive additives, and greater than or equal to about 0% weight fraction to less than or equal to about 20% weight fraction, optionally greater than or equal to about 0% weight fraction to less than or equal to about 10% weight fraction, and in some aspects, optionally greater than or equal to about 0% weight fraction to less than or equal to about 5% weight fraction of one or more binders. The positive electrode collector 34 can be formed of aluminum or any other conductive material known to those skilled in the art.

[0109] According to the present technology, the negative electrode (or anode) 22 includes a carbon material or carbon film having a first face and an opposing second face and defining a carbon matrix. As used herein, a "matrix" is an integral composition defined by a heterogeneous network of carbon molecules, particles or structures. As a non-limiting example, the carbon material or film includes carbon nanotubes, carbon nanofibers, carbon paper, graphene paper or a combination thereof. When unmodified, at least a portion of the carbon material or film is modified to include an increased number of lithium nucleation sites relative to the carbon matrix. The negative electrode 22 exhibits a state of charge (SOC) of greater than or equal to about 70%, greater than or equal to about 75%, or greater than or equal to about 80% after charging for 15 minutes (i.e., less than 16 minutes). During lithium plating and stripping cycles, the negative electrode 22 also exhibits a volume change of less than or equal to about 20%, less than or equal to about 15%, less than or equal to about 10%, less than or equal to about 5%, or less than or equal to 2%. For example, Figure 3A comparative electrode 97 is shown having lithium 98 disposed on opposite faces of a current collector 99. When the comparative electrode 97 undergoes plating 112 and stripping 114, the comparative electrode 97 undergoes a large volume change, which may lead to dendrite growth, low efficiency, and short life. In contrast, the negative electrode 22 of the present technology does not exhibit such a large volume change during cycling. Figures 4 to 7 Various aspects of negative electrode 22 are further described. Although negative electrode 22 has certain advantages when used as a negative electrode (ie, an anode), it is understood that it may additionally or alternatively be coated with a positive electroactive composition and used as a cathode.

[0110] exist Figure 4 In the present invention, the electrode 22a is prepared by obtaining a carbon material 100 having a first face 102 and an opposite second face 104 and modifying all or substantially all of the carbon material 100, the carbon material 100 being as described above (i.e., including carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof). The thickness of the carbon material 100 is greater than or equal to about 10 μm to less than or equal to about 100 μm, and the porosity is greater than or equal to about 30% to less than or equal to about 90%, wherein "porosity" is defined as the fraction of the total volume of pores to the total volume of the carbon material 100.

[0111] The modification causes defects on the surface of the carbon material 100 or throughout the carbon material 100, and is performed by laser ablation, contact with oxygen plasma, or wet chemical oxidation. In this way, the carbon material 100 can be physically and / or chemically modified. Modification by laser ablation includes, for example, scanning the carbon material 100 with a laser having a wavelength greater than or equal to about 800 nm to less than or equal to about 1200 nm (e.g., 1070 nm) and a power greater than or equal to about 200 W to less than or equal to about 500 W (e.g., 400 W), while using a scanning speed greater than or equal to about 0.5 m / s to less than or equal to about 5 m / s (e.g., 1.5 m / s), and a scanning overlap greater than or equal to about 20% to less than or equal to about 90% (e.g., 50%). The laser scanning causes defects in the carbon material 100 and generates the electrode 22a. Modification by oxygen plasma includes, for example, introducing a gas into a chamber containing the carbon material 100, the chamber presenting a negative pressure, i.e., a vacuum chamber. The gas contains greater than or equal to about 0% to less than or equal to about 99% argon (Ar) and the balance oxygen (O 2 The modification then involves exposing the gas to direct current (DC), radio frequency (RF), or microwave power to allow oxygen (O 2 ) and contacting the carbon material 100 with the ionized oxygen, wherein the ionized oxygen reacts with the carbon in the carbon material 100 to form carbon dioxide (CO 2), and causes defects in the carbon material 100, thereby forming the electrode 22a. Including argon in the gas can increase this etching effect and cause a higher level of defects to be formed on the carbon material 100 to form the electrode 22a. Modification by wet chemical oxidation includes, for example, contacting the carbon material 100 with a strong acid, which etches the carbon material 100, thereby introducing defects and forming the electrode 22a. As a non-limiting example, the strong acid can be HNO 3 , H 2 SO 4 , HCl, HF and combinations thereof.

[0112] After all or substantially all of the carbon material 100 is modified, an electrode 22a including the modified carbon material 106 is formed. "Substantially all" means that a portion of the electrode volume (such as less than or equal to about 20%, less than or equal to about 10%, or less than or equal to about 5%) may be unintentionally unmodified. Therefore, the electrode 22a contains, is substantially composed of, or is composed of the modified carbon material 106, wherein "substantially composed of the modified carbon material 106" means that the electrode 22a may also include only unavoidable impurities, such as a concentration of less than or equal to about 5% weight fraction based on the total weight of the electrode 22a (provided that it may also include lithium and optional solid electrolyte particles at nucleation sites, as described below). In certain aspects, the electrode 22a is substantially free of molecules covalently bonded to the modified carbon material 106, wherein "substantially free" means that only unintended and unavoidable impurities may be covalently bonded to the modified carbon material 106. Carbon material 100 is substantially flat and does not provide a sufficient number of nucleation sites for lithium, thereby avoiding large volume changes during cycling. In contrast, modified carbon material 106 has a complex three-dimensional microstructure and relatively more nucleation sites. Thus, modified carbon material 106 has an increased number of nucleation sites relative to carbon material 100. In addition, electrode 22a is a host for lithium ions (optional electrolyte), such as Figure 1 to Figure 2 Anode electrolyte 90, and current collector 32a are shown.

[0113] The electrode 22a is further processed by incorporating lithium into the modified carbon material 106 to form a lithium-modified electrode 22a' comprising a lithium-filled modified carbon material 108, which also serves as a lithium-modified current collector 32a'. As non-limiting examples, incorporation is performed by vacuum infiltration at high temperatures (e.g., at temperatures above the melting point of lithium metal), electrochemical plating, thermal evaporation, lithium foil lamination, and combinations thereof. Electrochemical plating includes placing the electrode 22a in an electrolyte that includes lithium (i.e., as a counter electrode) and applying an electric current. Thermal evaporation includes heating a solid lithium source, such as lithium metal, in a vacuum chamber containing the electrode 22a to induce the formation of lithium vapor covering the electrode 22a. Lithium foil lamination includes placing lithium foil on at least one face of the electrode 22a.

[0114] The lithium-modified electrode 22a' resists significant volume changes during cycling. For example, during plating 112, lithium is plated onto the lithium-modified electrode 22a' to generate a lithium-plated electrode 22a*, which also serves as a lithium-plated current collector 32a* having a lithium-plated modified carbon material 110. During stripping 114, the lithium-plated electrode 22a* returns to the form of the lithium-modified electrode 22a'. In particular, Figure 3 Compared to the comparative electrode 97, no significant volume change occurs during the plating 112 and stripping 114 of the lithium-modified electrode 22a' and the lithium-plated electrode 22a*, respectively.

[0115] exist Figure 5 In the present invention, an electrode 22b is prepared by obtaining a carbon material 100 having a first face 102 and an opposite second face 104 and modifying at least one of the first face 102 or the second face 104 of the carbon material 100, wherein the carbon material 100 is as described above (i.e., including carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof).

[0116] refer to Figure 4 The electrode 22a is modified by the same method as described above, but, for example, in a shorter time and / or with a lower power laser (i.e., when laser ablation is performed). In this way, the carbon material 100 can be physically modified. As a result of the modification, at least one of the first face 102 or the second face 104 of the electrode 22b includes a modified carbon material 106 (in this figure, both faces 102, 104 are modified) and at least the central portion of the electrode 22b is not modified and defines the collector 32b. Therefore, the electrode 22b contains, is essentially composed of, or consists of the modified carbon material 106 and the unmodified carbon material 100 defining the collector 32b, wherein "essentially composed of..." means that the electrode 22b may also include only unavoidable impurities, such as a concentration less than or equal to about 5% weight fraction based on the total weight of the electrode 22b (provided that it may also include lithium and optionally solid electrolyte particles at nucleation sites, as described below). In certain aspects, electrode 22b is substantially free of molecules covalently bonded to modified carbon material 106. Modified carbon material 106 has an increased number of nucleation sites relative to carbon material 100. In addition, electrode 22b is a host for lithium ions and an optional electrolyte, such as Figure 1 to Figure 2 Anolyte 90 is shown.

[0117] By reference Figure 4In the same manner as discussed above with respect to electrode 22a, electrode 22b is further processed by incorporating lithium into modified carbon material 106 to form a lithium-modified electrode 22b' comprising lithium-filled modified carbon material 108. Lithium-modified electrode 22b' is also resistant to significant volume changes during cycling. For example, during plating 112, lithium is plated onto lithium-modified electrode 22b' to produce lithium-plated electrode 22b* having lithium-plated modified carbon material 110. During stripping 114, lithium-plated electrode 22b* returns to the form of lithium-modified electrode 22b'. In particular, with Figure 3 Compared to the comparative electrode 97, no significant volume change occurs during the plating 112 and stripping 114 of the lithium-modified electrode 22b' and the lithium-plated electrode 22b*, respectively.

[0118] exist Figure 6 In the present invention, an electrode 22c is prepared by obtaining a carbon material 100 having a first face 102 and an opposite second face 104, the carbon material 100 being as described above (i.e., including carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof), and modifying at least one of the first face 102 or the second face 104 by disposing a layer containing a lithophilic material on at least one of the first face 102 or the second face 104 to define a modified carbon material 116, i.e., modified with a lithophilic layer. As non-limiting examples, the lithophilic material includes silver (Ag), gold (Au), aluminum (Al), tin (Sn), silicon (Si), and combinations thereof. The disposition is performed by electrochemical plating or vapor deposition (e.g., physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD)). The unmodified portion of the carbon material 100 defines the current collector 32c. The modified carbon material 116 (i.e., the lithophilic layer) has an increased number of nucleation sites relative to the carbon material 100. In addition, electrode 22c is a host for lithium ions and optional electrolytes such as Figure 1 to Figure 2 Anolyte 90 is shown.

[0119] By reference Figure 4 The electrode 22c is further processed by incorporating lithium into the modified carbon material 116 in the same manner discussed above to form a lithium-modified electrode 22c' comprising a lithium-filled modified carbon material 118 (i.e., a lithium-filled lithophilic layer). The lithium-modified electrode 22c' is also resistant to significant volume changes during cycling. For example, during plating 112, lithium is plated onto the lithium-modified electrode 22c' to produce a lithium-plated electrode 22c* having a lithium-plated modified carbon material 120. During stripping 114, the lithium-plated electrode 22c* returns to the form of the lithium-modified electrode 22c'. In particular, Figure 3 Compared to the comparative electrode 97, no significant volume change occurs during the plating 112 and stripping 114 of the lithium-modified electrode 22c' and the lithium-plated electrode 22c*, respectively.

[0120] exist Figure 7 In the present invention, an electrode 22d is prepared by obtaining a carbon material 100 having a first face 102 and an opposite second face 104, the carbon material 100 being as described above (i.e., including carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof), and modifying at least one of the first face 102 or the second face 104 by doping at least one of the first face 102 or the second face 104 with nitrogen (N), sulfur (S), phosphorus (P), boron (B), or a combination thereof to define a modified carbon material 122, i.e., a doped carbon material. Nitrogen (N) doping may be performed by contacting the carbon material 100 with nitrogen plasma, sulfur (S) doping may be performed by heat treating the carbon material 100 with phenyl disulfide, phosphorus (P) doping may be performed by heat treating the carbon material 100 with pentaphenylphosphoryl oxide, and boron (B) doping may be performed by heat treating the carbon material 100 with boric acid in an inert atmosphere (including, for example, argon or nitrogen). The heat treatment step described with respect to doping is performed at a temperature greater than or equal to about 500°C. The dopant renders the first face 102 and / or the second face 104 more lithophilic relative to the carbon material 100 when unmodified. The unmodified portion of the carbon material 100 defines a current collector 32d. The modified carbon material 122 (i.e., doped carbon material) has an increased number of nucleation sites relative to the carbon material 100. In addition, the electrode 22d is a host for lithium ions and an optional electrolyte, such as Figure 1 to Figure 2 Anolyte 90 is shown.

[0121] By reference Figure 4 The electrode 22d is further processed by incorporating lithium into the modified carbon material 122 in the same manner discussed above to form a lithium-modified electrode 22d' comprising a lithium-filled modified carbon material 124 (i.e., a lithium-filled doped carbon material). The lithium-modified electrode 22d' is also resistant to significant volume changes during cycling. For example, during plating 112, lithium is plated onto the lithium-modified electrode 22d' to produce a lithium-plated electrode 22d* having a lithium-plated modified carbon material 126. During stripping 114, the lithium-plated electrode 22d* returns to the form of the lithium-modified electrode 22d'. In particular, Figure 3 Compared to the comparative electrode 97, no significant volume change occurs during the plating 112 and stripping 114 of the lithium-modified electrode 22d' and the lithium-plated electrode 22d*, respectively.

[0122] Embodiments of the present technology are further illustrated by the following non-limiting examples.

[0123] Example

[0124] A carbon film including carbon nanotubes and carbon nanofibers was obtained and imaged by electron microscopy. The surface of the carbon film is shown at different magnifications. FIG. 8A to FIG. 8BThese micrographs show essentially flat and two-dimensional surfaces. Figure 8C A micrograph of a cross section of a carbon film is shown, which also shows a substantially flat and two-dimensional surface.

[0125] The carbon film was modified by laser ablation using a laser with a wavelength of 1070 nm and a power of 400 W, while adopting a scanning speed of 1.5 m / s and a scanning overlap of 50%. Fig. 9 shows a micrograph of the surface of a modified carbon film. In particular, when compared to the surface of an unmodified carbon film (see FIG. 8A to FIG. 8B ), the micrograph shows that the surface has depth (visible by the sharp and blurred parts of the surface), thus indicating that the surface is three-dimensional and has a higher surface area relative to the unmodified carbon film. Lithium is inserted into the modified carbon film by electrochemical plating to obtain a modified carbon film electrode. The modified carbon film electrode is analyzed with reference to a lithium foil electrode and an unmodified carbon film electrode containing lithium.

[0126] Fig.10 is a Nyquist plot obtained from electrochemical impedance spectroscopy (EIS). The Nyquist plot has a y-axis 150 representing the imaginary part of the impedance (-Im(Z) / Ohm) and an x-axis 152 representing the real part of the impedance (Re(Z) / Ohm). The Nyquist curves include a first curve 154 representing a lithium foil electrode, a second curve 156 representing an unmodified carbon film electrode, and a third curve 158 representing a modified carbon film electrode. The Nyquist plot shows that the relatively high surface area of ​​the modified carbon film electrode provides a lower impedance compared to the lithium foil electrode and the unmodified carbon film electrode having a relatively low surface area. The high surface area of ​​the modified carbon film electrode is conducive to the plating and stripping of lithium, which is indicated by the lower impedance.

[0127] The charging time of the unmodified carbon film electrode and the lithium foil electrode was analyzed and the data were plotted on Fig.11 The graph has a first y-axis 160 representing the battery voltage (volts), a first y-axis 161 representing the charge capacity (mAh / cm 2 ) and an x-axis 164 representing charging time (minutes). The dashed line represents the lithium foil electrode and the solid line represents the unmodified carbon film electrode. A curve for one cycle 166, a curve for two cycles 168, a curve for three cycles 170, and a curve for four cycles 172 are shown. The graph shows that the unmodified carbon film electrode has a faster charging time relative to the lithium foil electrode.

[0128] The charging time of the modified carbon film electrode and the unmodified carbon film electrode was analyzed and the data were plotted on Fig.12 The diagram has a first y-axis 180 representing the battery voltage (volts), a first y-axis 180 representing the charge capacity (mAh / cm 2) and an x-axis 184 representing charging time (minutes). The dashed line represents the unmodified carbon film electrode and the solid line represents the modified carbon film electrode. A curve for one cycle 186, a curve for two cycles 188, a curve for three cycles 190, and a curve for four cycles 192 are shown. The graph shows that the modified carbon film electrode has a faster charging time relative to the unmodified carbon film electrode. The modified carbon film electrode exhibited a state of charge (SOC) greater than 80% within 15 minutes.

[0129] Accelerated tests were also performed to compare the long-term cycling stability of the electrodes at fast charging rates. The charge and discharge tests were performed at 1.67 °C. Fig.13 This figure has representative discharge capacity (mAh / cm 2 ), a first y-axis 200 representing coulombic efficiency ("CE"; ​​%), a second y-axis 202 representing coulombic efficiency ("CE"; ​​%), and an x-axis 204 representing the number of cycles. A first curve 206 represents a lithium foil electrode, a second curve 208 represents an unmodified carbon film electrode, and a third curve 210 represents a modified carbon film electrode. An area 212 showing a 100% state of charge (SOC) and an area 214 showing an 80% state of charge (SOC) are provided in the figure. The figure shows that the unmodified carbon film electrode provides better long-term cycling stability relative to the lithium foil electrode. However, the modified carbon film electrode provides better long-term cycling stability relative to the unmodified carbon film electrode due to uniform plating and stripping (higher surface area leads to lower local current density).

[0130] For the purpose of illustration and description, the foregoing description of the embodiments has been provided. It is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable, and may be used in selected embodiments even if not specifically shown or described. The same may also be different in many ways. Such variations should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. An electrode for an electrochemical cell, the electrode comprising: a carbon film having a first side and an opposing second side, in, the first side and / or the opposing second side of the carbon film is modified such that the modified portion of the first side and / or the opposing second side of the carbon film comprises an increased number of lithium nucleation sites relative to an unmodified carbon film, wherein a central portion of the carbon film is unmodified and defines a current collector, and Wherein, the carbon film is modified in the following manner: The first face and / or the opposing second face is modified by a dopant; and / or The first face and / or the opposing second face are physically and / or chemically modified by laser ablation, oxygen plasma, wet chemical oxidation, or a combination thereof.

2. The electrode according to claim 1, wherein The carbon film is selected from carbon nanotubes, carbon nanofibers, carbon paper, graphene paper or a combination thereof.

3. The electrode according to claim 1, wherein The modified portion of the carbon film is greater than or equal to 80% of the volume of the carbon film.

4. The electrode according to claim 3, wherein The carbon film is substantially free of molecules covalently bonded to the carbon film.

5. The electrode according to claim 1, wherein The carbon film is substantially free of molecules covalently bonded to the carbon film.

6. The electrode according to claim 1, wherein The dopant includes nitrogen (N), sulfur (S), phosphorus (P), boron (B), or a combination thereof.

7. The electrode according to claim 1, wherein The electrode is an anode.

8. An electrochemical cell for cycling lithium ions, the electrochemical cell comprising the electrode according to claim 1.

9. An electrode for an electrochemical cell, the electrode comprising: a carbon material having a first face and an opposite second face, wherein the carbon material is selected from carbon nanotubes, carbon nanofibers, carbon paper, graphene paper or a combination thereof, in, the first face and / or the opposing second face of the carbon material is modified such that the modified portion of the first face and / or the opposing second face of the carbon material comprises an increased number of lithium nucleation sites relative to the unmodified carbon material, Wherein, the first surface and / or the opposite second surface of the carbon material is modified in the following manner: The first face and / or the opposing second face is modified by a dopant; and / or The first face and / or the opposing second face are physically and / or chemically modified by laser ablation, exposure to oxygen plasma or wet chemical oxidation or a combination thereof, and Therein, a central portion of the carbon material is not modified and defines a current collector.

10. The electrode according to claim 9, wherein The electrode exhibits a state of charge (SOC) of greater than or equal to 75% after charging for 15 minutes, and wherein the electrode also exhibits a volume change of less than or equal to 20% during lithium plating and stripping.

11. A method for manufacturing an electrode, the method comprising: obtaining a carbon material having a first face and an opposite second face, the carbon material being selected from carbon nanotubes, carbon nanofibers, carbon paper, graphene paper, or a combination thereof; and modifying the first face and / or the opposing second face of the carbon material such that the modified portion of the first face and / or the opposing second face of the carbon material comprises an increased number of lithium nucleation sites relative to the unmodified carbon material, in, A central portion of the carbon material is unmodified and defines a current collector, and Wherein, the carbon material is modified in the following manner: The first face and / or the opposing second face is modified by a dopant; and / or The first face and / or the opposing second face are physically and / or chemically modified by laser ablation, oxygen plasma, wet chemical oxidation, or a combination thereof.

12. The method according to claim 11, wherein: The modification is to modify the carbon material by laser ablation, oxygen plasma, wet chemical oxidation or a combination thereof, so that the modified carbon material is greater than or equal to 80% of the volume of the carbon material.

13. The method according to claim 11, wherein: The modification is to modify the carbon material by laser ablation, oxygen plasma, wet chemical oxidation or a combination thereof, so that the modified carbon material is greater than or equal to 90% of the volume of the carbon material.

14. The method according to claim 11, wherein: The modification is to modify the carbon material by laser ablation, oxygen plasma, wet chemical oxidation or a combination thereof, so that the modified carbon material is greater than or equal to 95% of the volume of the carbon material.

15. The method according to claim 11, wherein: The modification is doping at least one of the first face or the second face, and the central part of the carbon material between the first face and the second face is not modified, wherein the doping is: nitrogen doping by contact with nitrogen-generated or ammonia-generated plasma, sulfur doping by heat treatment with phenyl disulfide, phosphorus doping by heat treatment with pentaphenylphosphoryl oxide, or boron doping by heat treatment with boric acid.

16. The method according to claim 11, further comprising: Lithium is incorporated into the modified carbon material by vacuum infiltration, electrochemical plating, thermal evaporation, lithium foil lamination, or a combination thereof.

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