Long-cycle life, high-capacity silicon anode, and method for manufacturing and using the same anode.

Abstract

Materials, methods, electrodes, and devices related to high energy density, long life Li-ion batteries are provided. A lithium ion anode material contains a porous core with silicon and optionally carbon nanotubes, and a dense shell made of lithium vanadium oxide with an irregular rock salt structure. The lithium vanadium oxide acts as a solid intermediary layer for the anode material, overcoming the known problem of significant volume increase when silicon is lithiated. The lithium vanadium oxide is mechanically robust and resists electrolyte penetration. For these reasons, the anode material forms a very stable interface with the battery electrolyte. Experimental data is presented and discussed to demonstrate embodiments of the technology. It is shown that silicon anode materials can reversibly provide specific capacities greater than 2500 mA·h / g. The anode material exhibits excellent cycle stability and calendar life at room temperature as well as at elevated temperatures.

Description

[Technical Field]

[0001] Priority data This international patent application claims priority to U.S. Provisional Patent Application No. 63 / 151,547, filed on 19 February 2021 (the contents of which are incorporated into this specification by reference).

[0002] field This disclosure generally relates to lithium-ion batteries. More specifically, various embodiments relate to silicon-containing anode materials for lithium-ion battery materials. [Background technology]

[0003] background Rechargeable lithium-ion batteries that can be safely charged and discharged at high rates are desirable for electrified transportation, portable electronics, grid storage, and other applications. To meet society's increasingly growing demand for lithium-ion rechargeable batteries in electrical energy storage, novel electrode materials with high charge storage capacity are needed.

[0004] Large-volume modification forms of electrodes during repeated electrochemical cycles in lithium-ion batteries often limit their application due to stress formation, electrode breakage, and delamination from the current collector.

[0005] Silicon is one of the most promising anode materials for lithium-ion batteries due to its advantages such as the highest known capacity and relatively low working potential. However, there are three main problems with the practical implementation of Si anodes. First, the insufficient cycle life of silicon materials results from micro-grinding during very large volume fluctuations (up to 400%) associated with lithium ion intercalation and deintercalation. Second, extreme irreversible capacity loss and low Coulomb efficiency are caused by the mechanical fracture of the Si anode during the alloying / de-alloying process. Finally, the solid electrolyte intermediate phase (SEI) fractures when the nanostructures shrink during the delithiation of silicon. Exposure of the new silicon surface to the electrolyte causes the SEI to continue to thicken with each charge / discharge cycle. The formation and growth of the SEI consumes active lithium and electrolyte material, resulting in reduced specific capacity, higher battery resistance, and insufficient power density.

[0006] When a large number of Li atoms are introduced into the silicon electrode during lithiumization, the stable long-term performance of silicon as an anode material is limited due to very large volume expansion. Large volume increases often result in the formation of stress caused by volume changes, mechanical failure, and a decrease in specific capacity during repeated cycles, which are attributed to irreversible side reactions. Therefore, the development of Si-based Li-ion batteries faces significant challenges due to the volume changes and correlated capacity decay caused by repeated cycles.

[0007] In light of the aforementioned needs in the field of lithium-ion battery technology, improved anode materials, and in particular silicon-based anode materials, are required. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] overview This disclosure addresses the aforementioned needs in the art and is summarized herein, and is further described below in detail. [Means for solving the problem]

[0009] Some alternative forms are (a) A porous anode phase containing silicon, the porous anode phase and the porous phase being characterized by a porous phase volume porosity selected from about 5% to about 80%, and (b) A first solid medium layer disposed on the outside of the porous anode phase, the first solid medium layer containing a vanadium lithium oxide material, the vanadium lithium oxide material having a density of about 2.0 g / cm 3 ~ about 4.5 g / cm 3 and the vanadium lithium oxide material having a composition given by Li a V b O c (where a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are selected to balance the charge of Li a V b O c ) and Li a V b O c being reversibly lithiated, providing an anode material comprising a first solid medium layer.

[0010] In some embodiments, the anode material is a core - shell material in which the first solid medium layer forms a shell encapsulating the porous anode phase.

[0011] In some embodiments, the anode material is a sandwiched material in which the first solid medium layer is disposed on the outside of the first surface of the porous anode phase and the second solid medium layer is disposed on the outside of the second surface of the porous anode phase, where the second solid medium layer contains a vanadium lithium oxide material.

[0012] Li a V b O c can exist in a prelithiated state, where a = 0 in Li a V b O c . Instead, for example, before or during use of the anode material, Li a V b Oc Li exists in the lithium state, and here Li a V b O c In this case, a > 0.

[0013] Li a V b O c Li can be selected from the group consisting of Li3V2O5, Li4V2O5, Li5V2O5, LiVO2, LiV2O5, Li2V2O5, LiVO3, LiV3O8, Li2V3O8, Li3V3O8, LiV2O3, Li2V2O3, Li3V2O3, and combinations thereof. a V b O c Li is preferably crystalline. a V b O c Approximately 2.0 g / cm³ 3 ~Approx. 4.5g / cm 3 It can have a density of .

[0014] In a preferred embodiment, Li a V b O c At least 50% by weight, 60% by weight, 70% by weight, 80% by weight, 90% by weight, 95% by weight, or 99% by weight (e.g., 100% by weight) of

number

[0015] In some embodiments, the first solid mediating layer further contains a dopant M which is chemically or physically contained in the lithium vanadium oxide material, and whose composition is Li a V b O c M d (d=0.1~3, and a, b, c, and d are Li a V b O c M d It is given by (selected to equilibrium the charge of) and Lia V b O c M d However, it can be reversibly lithium-ized. The dopant M can be selected from the group consisting of, for example, Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof. Preferably, Li a V b O c M d At least 50% by weight or at least 90% by weight of

number

[0016] In some embodiments, the porousness of the porous phase volume is selected from about 20% to about 60%.

[0017] In some embodiments, silicon is present in the porous anode phase at a concentration of about 1% to 100% Si. The silicon may be amorphous silicon, polycrystalline silicon, or single-crystal silicon. The silicon may have an average particle size of, for example, about 10 nanometers to about 100 microns. The silicon may exist as particles having a geometric shape selected from the group consisting of, for example, spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

[0018] In some embodiments of the anode material, the porous anode phase does not contain carbon. In other embodiments of the anode material, the porous anode phase further contains carbon. The carbon may be selected from the group consisting of, for example, graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

[0019] The anode material may be present in the anode. The anode may further contain graphite, ungraphitized carbon, silicon dioxide, tin, tin oxide, or a combination thereof. The anode may further contain one or more binders optionally selected from the group consisting of, for example, carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof, or other homopolymers or copolymers.

[0020] The anode can exist within the cell along with the cathode. The cathode can be made of materials such as LiFePO4, LiMn2O4, or LiNi. 0.5 Mn 1.5 O4, LiSa x Co y Mn z O2(x+y+z=1), LiCoO2, LiNi x Co y Al z O2(x+y+z=1), LiFe x Mn y PO4(x+y=1), aLiNi x Co y Mn z The cathode material may be selected from the group consisting of O2·(1-a)Li2MnO3 (a=0 to 1 and x+y+z=1) and combinations thereof.

[0021] Another form provides an anode material containing both silicon and carbon in a porous anode phase, and the anode material is (a) A porous anode phase comprising a silicon-carbon composite containing silicon and carbon, characterized by a porous phase volume porosity selected from about 5% to about 80%, (b) A first solid mediating layer disposed on the outside of the porous anode phase, wherein the first solid mediating layer contains a lithium vanadium oxide material, and the lithium vanadium oxide material is present in a quantity of approximately 2.0 g / cm³ 3 ~Approx. 4.5g / cm 3 It has a density, and the lithium vanadium oxide material is Li a V b Oc (In the formula, a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are Li a V b O c Having a composition given by (selected to equilibrium the charge of), and Li a V b O c However, it includes a first solid mediating layer that can be reversibly lithified.

[0022] In some embodiments, the anode material is a core-shell material in which a first solid mediating layer forms a shell that encapsulates a porous anode phase.

[0023] In some embodiments, the anode material is a sandwiched material in which a first solid mediating layer is disposed outward on a first surface of a porous anode phase and a second solid mediating layer is disposed outward on a second surface of the porous anode phase, wherein the second solid mediating layer contains a lithium vanadium oxide material.

[0024] In certain embodiments, the porous phase volume porosity can be selected from about 20% to about 60%.

[0025] In some embodiments, silicon is present in the porous anode phase at a concentration of about 1% to 99.9% by weight Si. The silicon can have an average particle size of, for example, about 10 nanometers to about 100 microns. The silicon can exist as particles having a geometric shape selected from the group consisting of, for example, spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

[0026] In some embodiments, carbon is present in the porous anode phase at a concentration of about 0.1% to about 80% by weight. The carbon can be selected from the group consisting of, for example, graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

[0027] Li a Vb O c can exist in a prelithiated state, where Li a V b O c has a = 0. Alternatively, for example, before or during use of the anode material, Li a V b O c exists in a lithiated state, where Li a V b O c has a > 0.

[0028] Li a V b O​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​b O c M d (d=0.1~3, and a, b, c, and d are Li a V b O c M d It is given by (selected to equilibrium the charge of) and Li a V b O c M d However, it can be reversibly lithium-ized. The dopant M can be selected from the group consisting of, for example, Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof. Preferably, Li a V b O c M d At least 50% by weight or at least 90% by weight of

number

[0031] The anode material may be present in the anode. The anode may further contain graphite, ungraphitized carbon, silicon dioxide, tin, tin oxide, or a combination thereof. The anode may further contain one or more binders present in the anode at a concentration of about 0.1% to about 50% by weight. The binders may be selected from the group consisting of, for example, carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof, or other homopolymers or copolymers.

[0032] The anode can have an average anode thickness of, for example, about 200 nanometers to about 200 microns.

[0033] The anode can exist within the cell along with the cathode. The cathode can be, for example, LiFePO4, LiMn2O4, or LiNi 0.5Mn 1.5 O4, LiSa x Co y Mn z O2(x+y+z=1), LiCoO2, LiNi x Co y Al z O2(x+y+z=1), LiFe x Mn y PO4(x+y=1), aLiNi x Co y Mn z The cathode material may be selected from the group consisting of O2·(1-a)Li2MnO3 (a=0 to 1 and x+y+z=1) and combinations thereof.

[0034] Several alternative forms provide a method for producing anode material, and the method is (i) To provide a starting silicon-carbon composite containing silicon and carbon, (ii) Blending a starting silicon-carbon composite with a thermoplastic polymer having a melting point of approximately 300°C or less to produce a silicon-carbon-polymer composite, (iii) Solution coating of a silicon-carbon-polymer composite with a sol-gel solution containing vanadium oxide, thereby producing a silicon-carbon-polymer-vanadium oxide composite, (iv) Heat-treating a silicon-carbon-polymer-vanadium oxide composite at an effective temperature for decomposing and / or vaporizing the thermoplastic polymer, thereby generating a porous anode phase enclosed by a shell containing crystallized vanadium oxide, (v) The crystallized vanadium oxide is chemically lithified with a lithium-containing reducing agent, thereby Li a V b O c (In the formula, a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are Li a V b O c To produce a lithium vanadium oxide material having a composition given by (selected to equilibrium the charge of), (vi) recovering the anode material containing a porous anode phase encapsulated by a lithium vanadium oxide material.

[0035] In some methods, the porous anode phase is characterized by a volumetric porosity selected from approximately 5% to approximately 80%. In certain methods, the volumetric porosity is selected from approximately 20% to approximately 60%.

[0036] In some methods, silicon (in the porous anode phase) exists as particles having geometric shapes selected from the group consisting of spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

[0037] In some methods, the carbon (in the porous anode phase) is selected from the group consisting of graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

[0038] In some methods, in step (iii), vanadium oxide is V2O5 in a sol-gel solution.

[0039] In some methods, the effective temperature in step (iv) is selected from approximately 200°C to approximately 500°C, for example, from approximately 300°C to approximately 400°C. The thermoplastic polymer may be, for example, polylactide (PLA).

[0040] In some methods, lithium-containing reducing agents include butyllithium (LiC4H9) and lithium naphthalene (LiC4H9). 10 H8), Lithium anthracenate (LiC 14 The group is selected from H9) and combinations thereof.

[0041] In some methods, Li a V b O cThe group is selected from Li3V2O5, Li4V2O5, Li5V2O5, LiVO2, LiV2O5, Li2V2O5, LiVO3, LiV3O8, Li2V3O8, Li3V3O8, LiV2O3, Li2V2O3, Li3V2O3, and combinations thereof. Preferably, Li a V b O c At least 50% by weight of

number

number

[0042] In some methods, the lithium vanadium oxide material produced in step (v) is approximately 2.0 g / cm³. 3 ~Approx. 4.5g / cm 3 It has a density of .

[0043] The method may further include adding dopant M to a lithium vanadium oxide material, wherein the composition is Li a V b O c M d (d=0.1~3, and a, b, c, and d are Li a V b O c M d The dopant M is given by (selected to equilibrium the charge of). The dopant M can be selected from the group consisting of, for example, Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof. Preferably, Li a V b O c M dAt least 50% by weight or at least 90% by weight of

number

[0044] The method may further include introducing one or more additives to the anode material, selected from the group consisting of, for example, graphite, ungraphitized carbon, silicon dioxide, tin, tin oxide, or combinations thereof.

[0045] The method may further include introducing one or more binders selected from the group consisting of, for example, carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof, into the anode material.

[0046] In some alternative forms, the method further includes casting an anode material onto a first substrate to form an anode, laminating an electrolyte-containing separator onto the anode, casting a cathode material onto a second substrate to form a cathode, laminating the cathode onto the separator, and surrounding the anode, separator, and cathode with a current collector to form a cell.

[0047] In the formed cell, the electrolyte can be selected from the group consisting of liquid electrolytes, polymer gel electrolytes, and combinations thereof. Preferably, the lithium vanadium oxide material is impermeable to the electrolyte.

[0048] In the formed cells, the anode is approximately 0.2 mg / cm³. 2 ~about 50mg / cm 2 The anode material can be selected from the following proportions. The anode has a flow rate of approximately 0.05 mA·h / cm². 2 ~Approx. 10mA h / cm 2 The anode can have an area capacitance of at least one face selected from the following. In a particular embodiment, the anode has a capacitance of about 0.05 mA·h / cm².2 ~Approx. 10mA h / cm 2 It has area capacitance on both sides of the anode, which can be selected from the following. The anode thickness can be selected from, for example, about 200 nanometers to about 200 microns.

[0049] When the cell undergoes at least one charge-discharge cycle, the lithium vanadium oxide material preferably has a volume change of 0% to about 20% between charge-discharge cycles.

[0050] In a typical embodiment, the cell is repeatedly charged and discharged over multiple charge-discharge cycles, where Li a V b O c The cells are reversibly lithium-ionized and delithiated multiple times. The cells are charged and discharged for, for example, at least 1000 cycles. [Brief explanation of the drawing]

[0051] Brief explanation of the drawing [Figure 1] This includes several schematic diagrams comparing the latest technologies for Si anode design (structures 1 and 2) with the present technology, which provides c-LVO-void-Si / CNT as the anode material in several embodiments. [Figure 2] This includes several schematic diagrams illustrating several embodiments of LVO solid-mediated layers on silicon-carbon composites. [Figure 3] Includes several schematic diagrams illustrating the typical geometric shapes of c-LVO-void-Si / CNT anode materials. [Figure 4] In some embodiments, a typical process for producing c-LVO-void-Si / CNTs is shown. [Figure 5] In some embodiments, typical structures of patterned Si electrodes are illustrated. [Figure 6] In some embodiments, the performance of the LVO solid-mediated layer on Si is described. [Figure 7]In some embodiments, the performance of LVO solid-state mediating layers as intercalation hosts for lithium is described. [Figure 8] In some embodiments, preferred irregular rock salt structures of LVOs, as measured by neutron diffraction and X-ray diffraction, are illustrated. [Figure 9] The XRD spectra of the annealed Si thin film, Si-V2O5 thin film, and Si-V2O5 thin film in Example 1 are shown. [Figure 10] SEM and XRD images of the V2O5-Si-V2O5 3-layer thin film design in Example 2 are shown. [Figure 11] Example 3 includes four graphs of data from experiments conducted to test the techniques disclosed herein. [Figure 12] The image shows a photograph of the decomposed Si thin-film cell after 100 cycles in Example 3. [Figure 13] The graph shows the cycle repetition and calendar life test for Si compared to the LVO-Si-LVO thin film structure in Example 4. [Figure 14] To verify the advantages of the LVO layer in Example 5, a graph is shown that reveals the calendar lifetime at room temperature. [Figure 15] The following shows a series of SEM and XRD images of the decomposed, cycle-repeated cells in Example 6. [Modes for carrying out the invention]

[0052] Detailed description of the embodiment The principles, compositions, materials, systems, and methods of this disclosure will be described in detail by reference to various non-limiting embodiments of the technology.

[0053] This description will enable those skilled in the art to bring the technology to life and to use it, and it describes several embodiments, modifications, alternative forms, substitutes, and uses of the technology. These and other embodiments, features, and advantages of the technology will become even clearer to those skilled in the art when they refer to the following detailed description together with the accompanying drawings.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this art belongs.

[0055] Unless otherwise stated, all numbers used in this specification and in the claims, representing conditions, concentrations, dimensions, etc., should be understood in all cases to be modified by the term “approximately.” Therefore, unless otherwise indicated, the numerical parameters shown in the following specification and attached claims are approximations that may vary at least depending on the specific analytical technique.

[0056] The term "comprising," which is synonymous with "including," "containing," or "characterized by," is comprehensive or non-exclusive and does not exclude additional, unlisted elements or steps of the method. "Comprising" is a technical term used in the language of claims that the elements of the stated claim are essential, but other elements of the claims may be added to further form components within the scope of the claims.

[0057] When used herein, the phrase "consisting of" excludes any element, process, or component not explicitly stated in the claim. When the phrase "consists of" (or any other form thereof) appears in a clause of the claim text rather than immediately following the preamble, it limits itself to the elements specified in that clause. Other elements are not excluded from the claim as a whole. When used herein, the phrase "consisting essentially of" limits itself to the elements or processes of the method that specify the scope of the claim, and furthermore, those that do not essentially affect the basis and novel characteristics of the claimed material.

[0058] With respect to the terms “comprising” (synonymous with “including”), “consisting of”, and “consisting essentially of”, if any of these three terms is used herein, the disputed material disclosed and claimed herein may include the use of either of the other two terms, except as used in the Markush group. Thus, in some embodiments not explicitly enumerated, any instance of “comprising” may be replaced with “consisting of”, or instead, “consisting essentially of”. The term “including” should be interpreted as meaning “including, without limitation”, etc. The term “examples” is used to provide typical examples of items in the discussion, a non-exclusive or limited list thereof.

[0059] Adjectives such as “conventional,” “traditional,” “ordinary,” “standard,” and “known,” and similar terms, should not be interpreted as limiting the items described to items available up to or at any time in the present, but rather should be read as encompassing conventional, traditional, ordinary, or standard techniques that are available or may be known at any time now or in the future. Similarly, where this patent application refers to techniques that are obvious to those skilled in the art or are known, such techniques shall be encompassed by those techniques that are obvious to those skilled in the art or are known at any time now or in the future.

[0060] When used in this specification and the attached claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. The terms “a” or “an” should be read as meaning “at least one,” “one or more,” etc. The presence of expanding words and phrases such as “one or more,” “at least,” “not limited to,” or other similar words in some instances should not be read as meaning that a narrower case is intended or required in instances where such expanding words are absent.

[0061] Silicon (Si) is highly anticipated to increase the energy density of lithium-ion batteries due to its lithium storage capacity of 4200 mA·h / g, which is 10 times that of graphite. Research and development efforts have focused on improving the cycle life of Si, which is limited by the associated large volume changes linked to the non-mechanically compatible solid electrolyte interface (SEI) layer. The SEI layer is a passivation layer formed on the surface of the anode material of a lithium-ion battery as a result of electrolyte decomposition. The properties of the SEI layer play a crucial role in the cycleability, rate capacity, irreversible capacity loss, and safety of lithium-ion batteries.

[0062] Existing design criteria for long-life Si anodes are established, including maintaining electrical connectivity to Si during repeated cycles by suppressing particle fracture, as well as minimizing changes in electrochemical interface area and SEI layer fracture.

[0063] Current Si anode technology typically uses Si nanostructures that can accommodate volume changes without breakage. Si nanoparticles, nanowires, nanotubes, thin films, and porous structures have all demonstrated the ability to mitigate particle breakage. Nanostructures are often assembled into larger particles to minimize the contact area with the electrolyte. Otherwise, the large surface area of ​​the nanomaterial impairs SEI formation. Long cycle lifetimes of over 1000 cycles have been demonstrated in Li||Si half-cells. In addition to using nanostructures to mitigate breakage, some existing technologies have been developed to address the specific capacity range (i.e., Li x The cycle lifetime is improved by limiting x) in Si. In addition to the successful cycle repetition of Si in half-cells, progress has also been made in full-cells when the Si anode is paired with a 4V cathode. Several cells have been demonstrated to have stable cycle repetitions for 500 to 1000 cycles.

[0064] However, during storage, the capacity decay of Si cells has traditionally been a linear function of lifetime capacity throughput. This linear correlation indicates that the rate of active lithium consumption over the battery's lifespan is constant—the SEI is not effectively passivated. Despite the fact that graphite is known to be a good passivation material for the complex chemistry associated with the SEI layer, this problem has also been observed when the Si anode is coated with carbon. The chemical composition of the SEI layer can include various organic species (e.g., organic polymers) and non-organic species (e.g., LiF). The underlying Si structure exerts mechanical stress on the carbon surface coating, which is further transmitted to the SEI on the carbon. This can lead to continuous failure and spalling of the SEI, resulting in rapid capacity decay during storage or repeated cycles.

[0065] This invention is based in part on the use of high-density lithium vanadium oxide, which is ionic and electronically conductive as a solid mediating layer in long-cycle lifetime Si anode materials. When lithium vanadium oxide is densely densified, it is mechanically tougher and more impermeable to electrolytes than carbon. Furthermore, the polarity of lithium vanadium oxide also likely contributes to its sufficient adhesion to the SEI layer.

[0066] In addition to oxide shell materials that protect Si, it is desirable to select a Si structure that allows volume expansion while minimizing stress on the shell. Existing techniques attempt to use pomegranate-like structures. Secondary particles are usually sealed with a carbon coating, and Li + It conducts ions while suppressing the intrusion of electrolytes into the internal pores. However, there are challenges when creating pomegranate-like structures.

[0067] The present invention is based, at least in part, on the design of a porous anode phase having optimized porosity to absorb the volume expansion of silicon, while similarly utilizing the high-density lithium vanadium oxide described above. In some preferred embodiments, the techniques disclosed herein can be used to produce silicon sheets and carbon nanotube cores (the cores having internal porosity) and high-density LVO shells. In this disclosure, "LVO" is defined as Li in the absence of a dopant. a V b O c If one or more dopants exist, Li a V b O c M dThis means (see below for the ranges of a, b, c, and d). LVO is a recently discovered reversible host for lithium in the potential range between 0V and 2V. Its internal porosity absorbs the volume expansion of silicon during lithiation. The high-density layer features a very stable interface with the electrolyte, has minimal volume change and very rapid kinetics, and can deliver half its capacity in seconds. Compared to carbon, LVO is mechanically stronger and acts as a rapid charge transfer medium to Si.

[0068] Some alternative forms are (a) A porous anode phase containing silicon, characterized by a porous phase volume porosity selected from about 5% to about 80%, (b) A first solid mediating layer disposed on the outside of the porous anode phase, wherein the first solid mediating layer contains a lithium vanadium oxide material, and the lithium vanadium oxide material is present in a quantity of approximately 2.0 g / cm³ 3 ~Approx. 4.5g / cm 3 It has a density, and the lithium vanadium oxide material is Li a V b O c (In the formula, a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are Li a V b O c Having a composition given by (selected to equilibrium the charge of), and Li a V b O c The present invention provides an anode material comprising a first solid mediating layer that can be reversibly lithified.

[0069] In some embodiments, the anode material is a core-shell material in which a first solid mediating layer forms a shell that encapsulates a porous anode phase. "Encapsulating" means that the solid mediating layer completely seals the porous anode phase.

[0070] In some embodiments, the anode material is a sandwiched material in which a first solid mediating layer is disposed outward on a first surface of a porous anode phase and a second solid mediating layer is disposed outward on a second surface of the porous anode phase, wherein the second solid mediating layer contains a lithium vanadium oxide material.

[0071] Li a V b O c It can exist in a pre-lithiumized state, where Li a V b O c In this case, a=0. During use of the anode material, and possibly before use of the anode material, Li a V b O c Li exists in the lithium state, and here Li a V b O c In this case, a > 0. When in the lithium state, the value of a can be, for example, approximately 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.5, 4.0, 4.5, or 5.0.

[0072] Li a V b O c Li can be selected from the group consisting of Li3V2O5, Li4V2O5, Li5V2O5, LiVO2, LiV2O5, Li2V2O5, LiVO3, LiV3O8, Li2V3O8, Li3V3O8, LiV2O3, Li2V2O3, Li3V2O3, and combinations thereof. a V b O c Non-integer values ​​for a, b, and c are possible as long as the charge of is balanced.

[0073] Li a V b O cLi having at least 80% crystallinity or having a degree of crystallinity of at least 80%, at least 85%, at least 90%, at least 95%, at least 99%, or 100%. a V b O c In this specification, it is referred to as crystalline LVO or c-LVO. The crystallinity of LVO can be measured using X-ray diffraction.

[0074] Li a V b O c Approximately 2.0 g / cm³ 3 ~Approx. 4.5g / cm 3 It can have a density of Li. In various embodiments, Li a V b O c This includes a range of approximately, at least approximately, or at most approximately 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, or 4.5 g / cm³. 3 It has a density of .

[0075] In a preferred embodiment, Li a V b O c At least 50% by weight, 60% by weight, 70% by weight, 80% by weight, 90% by weight, 95% by weight, or 99% by weight (e.g., 100% by weight) of

number

[0076] In some embodiments, the first solid mediating layer further contains a dopant M which is chemically or physically contained in the lithium vanadium oxide material, and whose composition is Li a V b O c M d (d=0.1~3, and a, b, c, and d are Li a V b O c M d It is given by (selected to equilibrium the charge of) and Li a V b O c M d It can be reversibly lithium-ified.

[0077] The properties of LVO can be altered using dopants. For example, dopants can be used to modulate lithiation, delithiation, or other kinetics, lithiation ability, LVO stability, and / or other factors. Dopant M can be selected from the group consisting of, for example, Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof. Multiple dopants can be Li a V b O c M d They can be present within the formula, in which case each dopant in the empirical formula can have d = 0.1 to 3. A dopant may contain one or more divalent, trivalent, tetravalent, pentavalent, or hexavalent dopants.

[0078] Li a V b O c M d Approximately 2.0 g / cm³ 3 ~Approx. 4.5g / cm 3 It can have a density of Li. Preferably, Li a V b O c M dAt least 50% by weight or at least 90% by weight of

number

number

[0079] The thickness of the first solid mediator can be selected from, for example, about 5 nm to about 1 μm. In various embodiments, the thickness of the first solid mediator is about 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 225 nm, 250 nm, 275 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, or 950 nm, including any range in between (e.g., 10 to 300 nanometers). The thickness of the first solid mediator can be uniform throughout the anode material or can vary along the dimensions of the porous anode phase.

[0080] In embodiments using sandwiched materials rather than encapsulating materials, the thickness of the second solid mediating layer can be selected from, for example, about 5 nm to about 1 μm. In various embodiments, the thickness of the second solid mediating layer is about 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 225 nm, 250 nm, 275 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, or 950 nm, including any range in between (e.g., 10 to 300 nanometers). The thickness of the second solid mediating layer may be the same as or different from the thickness of the first solid mediating layer. Typically, the two thicknesses are the same or nearly the same, but in this case, that is not necessary.

[0081] The size of the porous anode phase can be selected from, for example, about 50 nm to about 100 μm. The size of the porous anode phase refers to the average effective diameter of the porous anode phase, where the effective diameter is the diameter of a sphere that has an equivalent volume as the volume of the porous anode phase, regardless of its geometric shape. In various embodiments, the size of the porous anode phase is about 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, including a range between any two.

[0082] In some embodiments, the porous phase volume porosity is selected from about 20% to about 60%. In various embodiments, the porous phase volume porosity is about, at least about, or at most about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, including any range in between (e.g., 10–70%, 30–50%, etc.).

[0083] In some embodiments, silicon is present in the porous anode phase at concentrations selected from about 1% to 100% by weight Si. In various embodiments, silicon is present in the porous anode phase at concentrations of about, at least about, or at most about 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98, 99, or 100% by weight, including any range in between.

[0084] Silicon can be amorphous silicon, polycrystalline silicon, or single-crystal silicon. Amorphous silicon particles can be present in a mixture with polycrystalline silicon particles. Polycrystalline silicon particles can be present in a mixture with single-crystal silicon particles. Amorphous silicon particles can be present in a mixture of both polycrystalline and single-crystal silicon particles.

[0085] Silicon particles can have an average particle size selected from, for example, about 10 nanometers to about 10 microns. In various embodiments, silicon particles have an average particle size of about, at least about, or at most about 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, including any range in between. In some embodiments, silicon particles are in the nanoparticle size range (less than 1000 nm). For non-spherical Si particles (e.g., sheets), the above sizes refer to the effective diameter, which is the diameter of a sphere having an equivalent volume as a Si particle of any shape.

[0086] Particle size can be measured by various techniques, such as dynamic light scattering, laser diffraction, or image analysis. Dynamic light scattering is a non-invasive, established technique typically used to measure the size and size distribution of particles in the submicron range down to 1 nanometer using state-of-the-art technology. Laser diffraction is a widely used particle size determination technique for materials ranging in size from several hundred nanometers to several millimeters. Typical dynamic light scattering and laser diffraction instruments for measuring particle size are available from Malver Instruments Ltd., Worcestershire, UK. Image analysis for estimating particle size and distribution can be performed directly using micrographs, scanning electron microscope images, or other images.

[0087] Silicon can exist as particles having geometric shapes selected from the group consisting of, for example, spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof. In certain embodiments, silicon mainly exists as Si sheets or nanosheets.

[0088] In some embodiments of the anode material, the porous anode phase does not contain carbon. In other embodiments of the anode material, the porous anode phase further contains carbon. The carbon may be selected from the group consisting of, for example, graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof. In addition to carbon nanotubes, other carbon nanostructures such as fullerenes are possible, and they may be geometrically hollow spheres, ellipsoids, tubes, sheets, or other shapes. The carbon may be nanoparticles, microparticles, or combinations thereof. In various embodiments, the carbon particles have an average particle size of approximately, at least approximately, or at most approximately 1 nm, 2 nm, 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, including a range in any of the above.

[0089] The anode material may be present in the anode. The anode may further contain graphite, ungraphitized carbon, silicon dioxide, tin, tin oxide, or a combination thereof. The anode may further contain one or more binders optionally selected from the group consisting of, for example, carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof, or other homopolymers or copolymers.

[0090] The anode can exist within a cell together with the cathode. A "cell" is an electrochemical cell that can either generate electrical energy from a chemical reaction or use electrical energy to cause a chemical reaction.

[0091] The cathode can be made of materials such as LiFePO4, LiMn2O4, or LiNi. 0.5 Mn 1.5 O4, LiSa x Co y Mn zO2(x+y+z=1), LiCoO2, LiNi x Co y Al z O2(x+y+z=1), LiFe x Mn y PO4(x+y=1), aLiNi x Co y Mn z The cathode material may be selected from the group consisting of O2·(1-a)Li2MnO3 (a=0 to 1 and x+y+z=1) and combinations thereof.

[0092] Another form provides an anode material containing both silicon and carbon in a porous anode phase, and the anode material is (a) A porous anode phase comprising a silicon-carbon composite containing silicon and carbon, characterized by a porous phase volume porosity selected from about 5% to about 80%, (b) A first solid mediating layer disposed on the outside of the porous anode phase, wherein the first solid mediating layer contains a lithium vanadium oxide material, and the lithium vanadium oxide material is present in a quantity of approximately 2.0 g / cm³ 3 ~Approx. 4.5g / cm 3 It has a density, and the lithium vanadium oxide material is Li a V b O c (In the formula, a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are Li a V b O c Having a composition given by (selected to equilibrium the charge of), and Li a V b O c However, it includes a first solid mediating layer that can be reversibly lithified.

[0093] In some embodiments, the anode material is a core-shell material in which a first solid mediating layer forms a shell that encapsulates a porous anode phase.

[0094] In some embodiments, the anode material is a sandwiched material in which a first solid mediating layer is disposed outward on a first surface of a porous anode phase and a second solid mediating layer is disposed outward on a second surface of the porous anode phase, wherein the second solid mediating layer contains a lithium vanadium oxide material.

[0095] In certain embodiments, the porous phase volume porosity can be selected from about 20% to about 60%. In various embodiments, the porous phase volume porosity is about, at least about, or at most about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, including any range in between (e.g., 10–70%, 30–50%, etc.).

[0096] In some embodiments, silicon is present in the porous anode phase at a concentration of about 1% to 99.9% by weight Si. In various embodiments, silicon is present in the porous anode phase at a concentration of about, at least about, or at most about 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98, 99, or 100% by weight, including any range in between.

[0097] Silicon can be amorphous silicon, polycrystalline silicon, or single-crystal silicon. Amorphous silicon particles can be present in a mixture with polycrystalline silicon particles. Polycrystalline silicon particles can be present in a mixture with single-crystal silicon particles. Amorphous silicon particles can be present in a mixture of both polycrystalline and single-crystal silicon particles.

[0098] Silicon particles can have an average particle size selected from, for example, about 10 nanometers to about 10 microns. In various embodiments, silicon particles have an average particle size of about, at least about, or at most about 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, including any range in between. In some embodiments, silicon particles are in the nanoparticle size range (less than 1000 nm). For non-spherical Si particles (e.g., sheets), the above sizes refer to the effective diameter, which is the diameter of a sphere having an equivalent volume as a Si particle of any shape.

[0099] Silicon can exist as particles having geometric shapes selected from the group consisting of, for example, spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

[0100] In some embodiments, carbon is present in the porous anode phase at concentrations ranging from about 0.1% to about 80% by weight. In various embodiments, carbon is present in the porous anode phase at concentrations ranging from at least about, or at most about 0.1, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80% by weight, including any range in between.

[0101] Carbon can be selected from the group consisting of, for example, graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

[0102] Li a V b O c It can exist in a pre-lithiumized state, where Li a V b O cIn this case, a=0. During use of the anode material, and possibly before use of the anode material, Li a V b O c It exists in a lithium state, where Li a V b O c In this case, a > 0. When in the lithium state, the value of a can be, for example, approximately 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.5, 4.0, 4.5, or 5.0.

[0103] Li a V b O c Li can be selected from the group consisting of Li3V2O5, Li4V2O5, Li5V2O5, LiVO2, LiV2O5, Li2V2O5, LiVO3, LiV3O8, Li2V3O8, Li3V3O8, LiV2O3, Li2V2O3, Li3V2O3, and combinations thereof. a V b O c Non-integer values ​​for a, b, and c are possible as long as the charge of is balanced.

[0104] Li a V b O c Li having at least 80% crystallinity or having a degree of crystallinity of at least 80%, at least 85%, at least 90%, at least 95%, at least 99%, or 100%. a V b O c In this specification, it is referred to as crystalline LVO or c-LVO. The crystallinity of LVO can be measured using X-ray diffraction.

[0105] Li a V b O c Approximately 2.0 g / cm³ 3 ~Approx. 4.5g / cm 3It can have a density of Li. In various embodiments, Li a V b O c This includes a range of approximately, at least approximately, or at most approximately 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, or 4.5 g / cm³. 3 It has a density of .

[0106] In a preferred embodiment, Li a V b O c At least 50% by weight, 60% by weight, 70% by weight, 80% by weight, 90% by weight, 95% by weight, or 99% by weight (e.g., 100% by weight) of

number

[0107] In some embodiments, the first solid mediating layer further contains a dopant M which is chemically or physically contained in the lithium vanadium oxide material, and whose composition is Li a V b O c M d (d=0.1~3, and a, b, c, and d are Li a V b O c M d It is given by (selected to equilibrium the charge of) and Li a V b O c M d However, it can be reversibly lithium-ized. The dopant M can be selected from the group consisting of, for example, Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof.

[0108] Li a Vb O c M d has a density of about 2.0 g / cm 3 to about 4.5 g / cm 3 and can have. Preferably, Li a V b O c M d at least 50 wt% or at least 90 wt% of

Number

Number

[0109] The thickness of the anode material can be selected, for example, from about 50 nm to about 10 μm. In various embodiments, the thickness of the anode material is about 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, including any range therebetween.

[0110] The thickness of the first solid medium layer can be selected, for example, from about 5 nm to about 1 μm. In various embodiments, the thickness of the first solid medium layer can be about 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 225 nm, 250 nm, 275 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, or 950 nm, including any intermediate range (e.g., 50 - 250 nanometers). The thickness of the first solid medium layer can be uniform across the entire anode material or can vary along the dimensions of the porous anode phase.

[0111] In embodiments using a sandwiched material rather than an encapsulating material, the thickness of the second solid medium layer can be selected, for example, from about 5 nm to about 1 μm. In various embodiments, the thickness of the second solid medium layer can be about 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, eight0 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 225 nm, 250 nm, 275 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, or 950 nm, including any intermediate range (e.g., 10 - 300 nanometers). The thickness of the second solid medium layer can be the same as or different from the thickness of the first solid medium layer. Typically, the two thicknesses are the same or approximately the same, but this is not necessary in this case.

[0112] The thickness of the porous anode phase can be selected from, for example, about 100 nm to about 100 μm. In various embodiments, the thickness of the porous anode phase is about 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, including any range in between.

[0113] In some embodiments, the porous phase volume porosity is selected from about 20% to about 60%. In various embodiments, the porous phase volume porosity is about, at least about, or at most about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, including a range in between any of these.

[0114] The anode material may be present within the anode. The anode may further contain graphite, ungraphitized carbon, silicon dioxide, tin, tin oxide, or a combination thereof.

[0115] The anode may further contain one or more binders present in the anode at concentrations selected from about 0.1% to about 50% by weight. In various embodiments, the anode contains one or more binders at concentrations of about 0.1, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% by weight, including any range in between.

[0116] The binder may be selected from the group consisting of, for example, carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof, or other homopolymers or copolymers.

[0117] The anode can have an average anode thickness selected from, for example, about 200 nanometers to about 200 microns. In various embodiments, the anode has an average anode thickness of about 200 nm, 300 nm, 400 nm, 500 nm, 1 μm, 2 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 75 μm, 100 μm, 125 μm, 150 μm, 175 μm, or 200 μm, including any range in between.

[0118] The anode can exist within the cell together with the cathode. The cathode can be, for example, LiFePO4, LiMn2O4, or LiNi 0.5 Mn 1.5 O4, LiSa x Co y Mn z O2(x+y+z=1), LiCoO2, LiNi x Co y Al z O2(x+y+z=1), LiFe x Mn y PO4(x+y=1), aLiNi x Co y Mn z The cathode material may be selected from the group consisting of O2·(1-a)Li2MnO3 (a=0 to 1 and x+y+z=1) and combinations thereof. A specific cathode material may be LiNi 0.8 Co 0.1 Mn 0.1 It is O2 (NMC811). For example, with 80 wt% Si, the anode material has a reversible capacitance of 2500 mA·h / g, and LiNi 0.8 Co 0.1 Mn 0.1 This facilitates the creation of 350 W·h / kg cells when paired with O2 cathodes and common carbonate-based electrolytes.

[0119] The techniques disclosed herein can be used in the design of batteries. A battery consists of one or more cells connected in parallel and / or in series. The battery configuration can vary widely, as is well known, for example, cylindrical, prismatic, and pouch cells. A battery may include, for example, an anode, a cathode, an additional Li source, and a current collector (e.g., copper foil).

[0120] In some embodiments, LVO-protected Si can be processed into an anode. In certain embodiments, LVO-protected Si can be pre-lithified to compensate for the Li raw material. The negative electrode (anode) is LiNi 0.8 Co 0.1 Mn 0.1 It can be paired with a 4V cathode such as O2. Pouch-type cells can be manufactured by stacking electrodes alternately, or cylinder cells can be manufactured by winding them up. The cells can provide a high energy density of 350 W·h / kg or more.

[0121] The battery can use one or more electrolytes selected from, for example, non-aqueous electrolytes, aqueous electrolytes, and ionic liquids. The electrolyte generally contains a lithium salt (anion + lithium cation) in a solvent.

[0122] Lithium salts include, but are not limited to, LiClO4, LiBF4, LiPF6, LiCF3SO3, LiCF3CO2, LiN(FSO2)2 (lithium bis(fluorosulfonyl)imide), LiN(CF3SO2)2 (lithium bis(trifluoromethanesulfonyl)imide), LiAsF6, LiSbF6, LiAlCl4, LiCl, LiBr, and LiI, and can be used individually or as a mixture of two or more. In some embodiments, LiBF4 and LiPF6 are preferred.

[0123] Examples of solvents that can be used as electrolytes include propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, methyl formate, methyl acetate, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, dioxane, acetonitrile, nitromethane, and ethyl This includes aprotic organic solvents such as monoglyme, triesters phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, 3-methyl-2-oxazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethyl ether, 1,3-propanesultone, N-methylacetamide, acetonitrile, acetal, ketal, sulfone, sulfolane, aliphatic ether, cyclic ether, glyme, polyether, phosphate ester, siloxane, dioxolane, and N-alkylpyrrolidone. Other components and impurities, known in the art, may be present in small amounts in the electrolyte.

[0124] In some embodiments, the technology disclosed herein can be used in novel battery systems that are superior to conventional graphite battery packs and have fewer cells in the battery pack. This battery system can utilize any one (or more) of the disclosed anode structures and can be paired with a 4V high-capacity cathode such as Li-rich oxide and / or Li(NiMnCo)O2 layered oxide. This battery system can achieve a specific energy of over 350 W·h / kg. The battery voltage can be over 3.7V. The battery can be 1000 cycles with <10% capacity loss and can be stable after storage at 55°C for two weeks with <10% capacity loss. This high-energy-density battery system is suitable for many commercial applications, such as electric vehicles, smart devices, and high-power portable devices with high energy density.

[0125] In some embodiments, the anode materials disclosed herein have a unique structure that enables long cycle lifetimes (e.g., up to 3000 cycles or more) and long calendar lifetimes (e.g., up to 10 or more) due to the complete absence of contact between the electrolyte and Si. Furthermore, the carbon (e.g., CNT) network structure provides mechanical support to the LVO shell, reducing mechanical stress during calendering and repeated cycling. Experimental results using LVO / Si multilayer structures (see Examples) confirm that LVO can isolate Si from the liquid electrolyte, resulting in stable repeated cycling and dramatically improved Coulomb efficiency under storage at 55°C.

[0126] One typical method for producing anode material is as follows: Internal void spaces can be created by thermal evaporation of poly(lactic acid) (PLA) at a suitable temperature such as 200°C, leaving no residual organic compounds. PLA is a thermoplastic with a melting point of 160°C and is also soluble in, for example, propylene carbonate, which allows for the production of core structures by simple melt blending or precipitation from emulsions. Shell structures can be formed by solution coating from a V2O5 sol-gel solution followed by moderate heat treatment at 350°C, which evaporates the PLA, crystallizes the oxide, and seals the shell. Then, LVO shell structures can be produced using chemical lithiation.

[0127] Several alternative forms provide a method for producing anode materials, and this method is (i) To provide a starting silicon-carbon composite containing silicon and carbon, (ii) Blending a starting silicon-carbon composite with a thermoplastic polymer having a melting point of approximately 300°C or less to produce a silicon-carbon-polymer composite, (iii) Solution coating of a silicon-carbon-polymer composite with a sol-gel solution containing vanadium oxide, thereby producing a silicon-carbon-polymer-vanadium oxide composite, (iv) Heat-treat the silicon-carbon-polymer-vanadium oxide composite at an effective temperature to decompose and / or vaporize the thermoplastic polymer, thereby producing a porous anode phase encapsulated by a shell containing crystallized vanadium oxide. (v) Chemically lithiate the crystallized vanadium oxide with a lithium-containing reducing agent, thereby producing a vanadium oxide lithium material having a composition given by Li a V b O c (where a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are selected to balance the charge of Li a V b O c ). (vi) Recovering an anode material containing a porous anode phase encapsulated by the vanadium oxide lithium material.

[0128] In some methods, the porous anode phase is characterized by a volume porosity selected from about 5% to about 80%. In certain methods, the volume porosity is selected from about 20% to about 60%.

[0129] In some methods, silicon (in the porous anode phase) is present as particles having a geometric shape of particles selected from the group consisting of spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

[0130] In some methods, carbon (in the porous anode phase) is selected from the group consisting of graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

[0131] In some methods, in step (iii), the vanadium oxide is V2O5 in a sol-gel solution. Other vanadium oxides include VO, V2O3, VO2, V3O5, V3O7, V4O9, V6O 13 、V4O7、V5O9、V6O 11 、V7O13 andV8O 15 This includes, but is not limited to, those mentioned above.

[0132] In some methods, the effective temperature in step (iv) is selected from approximately 200°C to approximately 500°C, for example, from approximately 300°C to approximately 400°C. In various embodiments, the temperature in step (iv) is approximately, at least approximately, or at most approximately 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, or 600°C, including any range in between.

[0133] The thermoplastic polymer may be, for example, polylactide (PLA). Other thermoplastic polymers that can be used include, but are not limited to, polyhydroxyalkanoates, polyethylene, polypropylene, and polyethylene terephthalate.

[0134] In some methods, lithium-containing reducing agents include butyllithium (LiC4H9) and lithium naphthalene (LiC4H9). 10 H8), Lithium anthracenate (LiC 14 The group is selected from H9) and combinations thereof.

[0135] In some methods, Li a V b O c The group is selected from Li3V2O5, Li4V2O5, Li5V2O5, LiVO2, LiV2O5, Li2V2O5, LiVO3, LiV3O8, Li2V3O8, Li3V3O8, LiV2O3, Li2V2O3, Li3V2O3, and combinations thereof. Preferably, Li a V b O c At least 50% by weight of

number

number

[0136] In some methods, the lithium vanadium oxide material produced in step (v) is approximately 2.0 g / cm³. 3 ~Approx. 4.5g / cm 3 It has a density of Li. In various embodiments, Li a V b O c This includes a range of approximately, at least approximately, or at most approximately 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, or 4.5 g / cm³. 3 It has a density of .

[0137] The method may further include adding dopant M to the LVO material, wherein its composition is Li a V b O c M d (d=0.1~3, and a, b, c, and d are Li a V b O c M d The dopant M is given by (selected to equilibrium the charge of). The dopant M can be selected from the group consisting of, for example, Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof. Preferably, Li a V b O c M d At least 50% by weight or at least 90% by weight of

number

[0138] The method may further include introducing one or more additives to the anode material, selected from the group consisting of, for example, graphite, ungraphitized carbon, silicon dioxide, tin, tin oxide, or combinations thereof.

[0139] The method may further include introducing one or more binders selected from the group consisting of, for example, carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof, into the anode material.

[0140] In some alternative forms, the method further includes casting an anode material onto a first substrate to form an anode, laminating an electrolyte-containing separator onto the anode, casting a cathode material onto a second substrate to form a cathode, laminating the cathode onto the separator, and surrounding the anode, separator, and cathode with a current collector to form a cell. In the formed cell, the electrolyte may be selected from the group consisting of liquid electrolytes, polymer gel electrolytes, and combinations thereof.

[0141] Preferably, the lithium vanadium oxide material is impermeable to the electrolyte. "Impermeable" means that during repeated cell cycles, 0.1% by weight or less of the electrolyte penetrates the lithium vanadium oxide material, deposits within the SEI layer, and / or penetrates into the porous anode phase. Preferably, 0.01% by weight or less, more preferably 0.001% by weight or less of the electrolyte penetrates the lithium vanadium oxide material. Most preferably, no detectable electrolyte penetrates the lithium vanadium oxide material at all. It should be noted that certain electrolytes may be adsorbed onto the lithium vanadium oxide material or partially absorbed into the lithium vanadium oxide material, but still do not penetrate throughout the entire lithium vanadium oxide material.

[0142] In the formed cells, the anode is approximately 0.2 mg / cm³.2 ~about 50mg / cm 2 The anode material content can be selected from the following. In various embodiments, the anode material content may be about or at least about 0.2, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 mg / cm³, including a range between any of these. 2 That is the case.

[0143] The anode has a current of approximately 0.05 mA·h / cm². 2 ~Approx. 10mA h / cm 2 The anode can have an area capacitance of at least one face selected from the following. In a particular embodiment, the anode has a capacitance of about 0.05 mA·h / cm². 2 ~Approx. 10mA h / cm 2 The anode has area capacitance on both sides, selected from the following. In various embodiments, the anode has a capacitance of approximately, or at least approximately, 0.05, 0.1, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, or 10 mA·h / cm², including a range between any two. 2 It has area capacity on both sides of the anode.

[0144] In a typical embodiment, the cell is repeatedly charged and discharged over multiple charge-discharge cycles, where Li a V b O c The cells are reversibly lithiumized and delithiated multiple times. The cells can be charged and discharged for, for example, at least 1000 cycles. In various embodiments, the number of charge-discharge cycles can be, for example, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1500, 2000, 2500, 3000, 3500, 4000, 4500, or 5000, or more.

[0145] When the cell undergoes at least one charge-discharge cycle, the lithium vanadium oxide material preferably has a volume change of 0% to about 20% between charge-discharge cycles. In various embodiments, after one charge-discharge cycle, the lithium vanadium oxide material has a volume change of about, or at most about 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, or 0.0%. In various embodiments, after 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 charge-discharge cycles, the lithium vanadium oxide material has a viscosity of approximately 20%, 19%, 18%, including a range between any of these. It has a volume change of %, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, or 0.0%.

[0146] The art disclosed herein by various embodiments is described in more detail here with reference to the drawings (Figures 1-15). The drawings are provided for illustrative purposes only and merely represent typical or exemplary embodiments of the art disclosed. These drawings are provided to facilitate the reader's understanding of the art disclosed and should not be considered to limit its width, scope, or applicability. For clarity and ease of explanation, it should be noted that these drawings are not necessarily to scale.

[0147] Figure 1 includes several schematic diagrams comparing the latest techniques for Si anode design (structures 1 and 2) with the present technique, which provides c-LVO-void-Si / CNT as the anode material in several embodiments.

[0148] Structure 1 (prior art) in Figure 1 can be obtained by a multi-step process as follows: First, Si is oxidized to form an SiO2-Si core-shell structure (SiO2 shell and Si core), which is then coated with a resorcinol-formaldehyde gel. Next, the structure is made into multiple sizes to form a C-SiO2-Si structure (C outer shell, SiO2 inner shell, and Si core). Then, SiO2 is etched with hydrogen fluoride to form a C-void-Si structure (C shell, void space, and Si core). Unfortunately, the carbon matrix is ​​inherently porous, as can be seen from the etching process. These internal pores present a challenge in electrolyte penetration, leading to the formation of SEI inside.

[0149] Structure 2 (prior art) in Figure 1 uses chemical vapor deposition (CVD) to deposit nano-Si into a porous carbon network structure from a silane source, followed by CVD of the carbon coating. This method can, in some cases, yield a high-density coating. However, the coating thickness and robustness during repeated cycles are unknown. Furthermore, the CVD Si process needs to be controlled with great precision to obtain the desired size and distribution of Si, which greatly reduces its ease of scaling.

[0150] In contrast to structures 1 and 2, the structure c-LVO-void-Si / CNT in Figure 1 is provided by this technology. c-LVO is crystalline lithium vanadium oxide that functions as a high-density solid mediating layer. c-LVO forms a shell around a core consisting of Si, carbon nanotubes (CNTs), and voids. "Si / CNT" can be referred to as a silicon-carbon composite, "void-Si / CNT" as a porous anode phase, and c-LVO as a solid mediating layer. The solid mediating layer c-LVO is positioned outward on the void-Si / CNT porous anode phase. Carbon nanotubes are shown as long, undulating tubes in the c-LVO-void-Si / CNT structure in Figure 1. Other forms of carbon, such as graphene or carbon fibers, can be used instead of CNTs.

[0151] As shown in Figure 1, the c-LVO-void-Si / CNT anode material can include a Si sheet and a carbon nanotube core with internal porosity (from voids) that absorbs the volume expansion of Si. The approximately 10% porosity in Figure 1 is for illustrative purposes only, and the volume porosity of the porous phase can generally range from, for example, about 5% to about 80%. The shell is, but is not limited to, Li 3+x It is produced from high-density crystalline lithium vanadium oxide (c-LVO) such as V2O5 (x=0~2). 3+x V2O5 replaces the commonly used carbon coatings in conventional nanostructured Si anodes. The anode material disclosed herein forms a highly stable interface (SEI layer in Figure 1) with the battery electrolyte. The anode material demonstrates excellent cycle repeatability (long cycle life) and long calendar life.

[0152] Figure 2 includes several schematic diagrams illustrating embodiments of LVO solid-mediated layers on silicon-carbon composites. LVO-void-Si / CNT starting materials are provided. The crystalline vanadium lithium oxide (c-LVO) shell is dense, highly ionically conductive, and impermeable to electrolytes. Lithitation is carried out along with the SEI layer, LVO-void-Li xForms Si / CNT material. The LVO shell prevents the penetration of electrolyte. LVO-void-Li x When Si / CNTs are delithified, LVO-void-Si / CNTs are reformed, leaving behind an SEI layer, and the LVO shell further inhibits the penetration of electrolytes.

[0153] In embodiments of the technology disclosed herein, such as the embodiment shown in Figure 2, the LVO protective layer provides several important features: (1) The LVO layer is lithium-ion conductive. (2) The LVO layer is impermeable to electrolytes. (3) The LVO layer can form a stable SEI together with the electrolyte, which is completely passivated at the constant interface area. (4) The LVO layer is an effective intercalation host for lithium in the Si operating potential region. (5) The LVO layer is mechanically tough.

[0154] In some embodiments, the anode material has a discharge capacity exceeding 2500 mA·h / g, which is significantly higher than that of graphite anodes. Furthermore, the anode material can achieve long cycle life and calendar life without complex manufacturing processes. In some embodiments, the anode material can perform 1000 cycles with less than 10% capacity loss. In some embodiments, the anode material maintains stability after storage at 55°C for two weeks with less than 10% capacity loss. This anode material enables long-life, high-energy cells with a specific energy density greater than 350 W·h / kg.

[0155] Figure 3 includes several schematic diagrams illustrating typical geometric shapes of c-LVO-void-Si / CNT anode materials. Typical geometric shapes include elliptical, spherical, and layered structures. The introduction of a CNT network structure within the core provides substantial mechanical support to the LVO shell during compression and releases stress on the shell itself. The LVO shell is preferably sufficiently ductile to respond to silicon expansion without fracture, resulting in excellent protection of Si from the electrolyte.

[0156] Figure 4 shows a typical process for producing c-LVO-void-Si / CNTs. Si particles (e.g., Si sheets) are mixed with CNTs and PLA to form a PLA-Si / CNT core, which is then coated with a V2O5 gel dissolved in H2O2 using sol-gel technology to form a-V2O5-PLA-Si / CNT (a-V2O5 = amorphous V2O5) as a composite gel. PLA is selected in some embodiments because it can decompose and evaporate at 200°C long before V2O5 crystallizes at 350°C (c-V2O5 = crystalline V2O5). The PLA is optionally doped with a catalytic amount of SnO2. The composite gel is heated to evaporate the solvent, after which the PLA decomposes, vaporizing at 200-300°C to form gaseous products. Further heating to 350°C promotes the crystallization of V2O5 to produce c-V2O5 (crystalline V2O5), eliminating porosity within the shell. Chemical lithiation with lithium metal and / or butyllithium converts c-V2O5 into a c-LVO solid mediating layer, thereby forming the final c-LVO-void-Si / CNT material. This method forms a hollow structure without using chemical etching or chemical vapor deposition, seals the shell by crystallization, and achieves an ideal structure through a process flow that is scalable.

[0157] Figure 5 illustrates typical structures of patterned Si electrodes in several embodiments. The Si array on copper (Cu) can be fabricated using a nickel (Ni) mesh grid as a mask. Using LVO-Si multilayer structures fabricated by electron beam evaporation, the thickness requirements of the LVO-Si can be investigated to prevent LVO degradation and electrolyte penetration into the Si during repeated electrochemical cycles. Two embodiments are shown in Figure 5: a first embodiment in which the Si is completely encapsulated, and a second embodiment in which the sides of the Si are exposed.

[0158] The first structure (Figure 5, lower left) is a completely sealed structure, i.e., patterned Si completely sealed by LVO. The Si may or may not contain carbon (e.g., CNTs). For example, a Cu foil substrate is first coated with V2O5 by electron beam evaporation. Next, a Ni mesh is attached as a convenient mask (the mask is shown at the top of Figure 5), in firm contact with the surface, and the patterned Si film is grown by electron beam evaporation. The superstructure in Figure 5 is a top view of a typical mask. Meshes are available in different sizes, e.g., 2000 mesh (with a hole size of 7.6 μm × 7.6 μm). Using lithography techniques, pattern sizes down to a minimum of 1 μm can be used. The Si thickness is controlled by the deposition time. Next, the mask is removed, and another layer of V2O5 is deposited as a capping layer. Then, the entire structure is thermally annealed at 350°C for, for example, 1 hour to promote crystallization of V2O5. Next, the crystallized V2O5 is lithium-ionized to form LVO. The sides of the Si layer are sealed (completely sealed) with LVO.

[0159] In the first embodiment of Figure 5, for example, the Si pattern size can be about 1 μm to about 10 μm, the film thickness can be about 50 nm to about 1 μm or more, and the LVO thickness can be about 10 nm to about 300 nm. The mechanical properties of the LVO allow for the use of thicker Si films (i.e., >1 μm). In certain embodiments, Si islands having the same order of height and size help to minimize the effect of the substrate, so that the observed mechanical stability directly reflects the Si / LVO interaction.

[0160] In the second embodiment (Figure 5, lower right), an LVO / Si / LVO sandwich structure having the same size and thickness as in the first embodiment is deposited. The only necessary change during manufacturing is the use of a mask (top of Figure 5) for the deposition of all three layers (LVO, then Si, then another LVO). After each LVO layer is formed, or after all layers have been manufactured, crystallized V2O5 can be lithified to form LVO. In this second embodiment, the sides of the Si layer are not sealed. Therefore, the Si layer is not directly mechanically constrained, and its edges are in contact with the liquid electrolyte. However, when there is a small ratio between thickness and size, the relative contact area is very small. Furthermore, the Si film expands freely in the height direction.

[0161] Compared to prior art, both approaches in Figure 5 can better absorb the volume change of Si during repeated cycles and can mitigate abscission and capacitance loss by minimizing the stress applied by the Cu substrate.

[0162] Figure 6 illustrates the performance of a typical LVO solid-mediated layer on Si. The LVO is an intercalation host for lithium in the 0–2V range and has substantial capacitance over the Si cycle repetition potential range. At the Si delithiation potential (up to 1V), the LVO operates in its state of charge (SOC) while the graphite is completely delithified. This property is crucial for the LVO to function as a redox medium to Si.

[0163] Figure 6(a) shows the charge-discharge profile of LVO, with charge-discharge profiles of silicon and graphite included for comparison. Figure 6(b) shows simulated charge-discharge curves for different Si / LVO ratios. The simulated charge-discharge curves show that the capacity changes with the ratio between Si and LVO. At high Si content, such as 80 wt%, the capacity contribution from LVO is negligible, and the electrode has a reversible capacity of 2500 mA·h / g. All volume changes from Si are explained by voids in the particles, and therefore electrode expansion is expected to be minimal.

[0164] Figure 7 illustrates the performance of the LVO solid mediation layer as an intercalation host for lithium. V2O5 is a well-studied cathode material. When lithiated up to 1.5V, V2O5 forms Li3V2O5 with an irregular rock salt structure. In some embodiments, the irregular rock salt phase can receive even more lithium when further lithiated to form Li4V2O5 or Li5V2O5, resulting in a reversible capacitance of 260 mA·h / g. In contrast to TiO2, for example, there is very little hysteresis between lithiation and delithiation. As illustrated in Figure 7, LVO is one of the few oxides that undergo stable intercalation rather than decomposition between 0 and 1V. LVO is an intercalation host for lithium in the 0-2V range and has substantial capacitance in the potential range of Si cycle repetitions. LVO has extremely rapid kinetics and very good cycle repetition stability, which makes it preferable for protecting Si. Therefore, LVO is a very stable intercalation host for lithium.

[0165] Figure 8 illustrates the preferred disordered rock salt structure of LVO as measured by neutron diffraction and X-ray diffraction. Figure 8 shows that the disordered rock salt structure is well maintained during repeated cycles. In some embodiments, the SEI layer is formed on the oxide surface as expected in this potential range. In some embodiments, structural improvements show that the change in lattice parameters is only 1.8%, which translates to a volume change of 5.5%—much smaller than that of smooth graphite. This small volume change results in very good cycle repeatability, with only slight capacity decay for 1000 cycles, as shown in Figure 7(b). The material also exhibits very good rate capability, supplying half of its capacity at 20 A / g or less than 20 seconds, as illustrated by Figure 7(a). The stability of LVO, high rate capability, and working potential make it an ideal material to serve as a protective layer for Si. [Examples]

[0166] Examples The following experiments were conducted to test the disclosed technology. These experiments are not intended to limit the scope of the present invention.

[0167] Example 1: Preparation of thin film material. In the experiments of this embodiment, Si and V2O5 thin films were deposited on a Cu substrate by electron beam evaporation. For the basic experiments, a 200 nm thick Si thin film was selected on the Cu substrate. To physically protect and confine the Si film, a 300 nm thick V2O5 film was deposited on both the top and bottom surfaces of the Si film, and then annealed to achieve the crystalline phase of V2O5.

[0168] The crystalline structure of the material was confirmed by X-ray diffraction (XRD). Figure 9 shows the XRD spectra of a Si thin film, a Si-V2O5 thin film, and a Si-V2O5 thin film after annealing. V2O5 showed an amorphous structure after deposition, indicating poor electrochemical performance. However, a crystalline phase appeared after annealing. After lithiation of V2O5, the disordered rock salt phase Li3V2O5 exhibits considerable mixed conductivity and high reversible capacitance. The Li3V2O5 film exhibits excellent electrochemical cycle repetition.

[0169] Example 2: SEM analysis of a V2O5-Si-V2O5 3-layer structure. To analyze the structure of the V2O5-Si-V2O53 layer, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (XRD) were performed, and the results are shown in Figure 10.

[0170] As is evident in Figure 10(a), the top surface of the three layers was extremely smooth after annealing, with no cracks or delamination whatsoever. The thickness of the three-layer film was measured using the cross-sectional SEM image shown in Figure 10(b). The total thickness was approximately 800 nm, which is consistent with the reading from the electron beam evaporator sensor.

[0171] Elemental analysis was performed using XRD to create a composition chart of the thin film. As shown in Figure 10(c), the signal for element Si was concentrated in the center of the film. As shown in Figure 10(d), the signal for element V was concentrated on the top and bottom surfaces, indicating a Si and V2O5 sandwich structure where V2O5 is arranged outward on each surface of Si. Based on the XRD image, the thickness of the Si layer is approximately 200 nm, and the thickness of the two V2O5 films is approximately 300 nm.

[0172] These SEM and EDX images illustrate a three-layer thin-film design, which is one embodiment of the technology disclosed herein.

[0173] Example 3: Test Li|| thin-film anode battery. Figure 11 includes four graphs of data from experiments conducted to test the techniques disclosed herein. In particular, Figure 11 shows how the specific capacity and cycle rate of an LVO-Si-LVO sandwich structure used in some embodiments of the techniques disclosed herein are compared to the specific capacity and cycle rate of an unprotected Si film. Figure 11(a) shows the cycle performance of a Si thin film, Figure 11(b) shows the voltage profile of a Si thin film, Figure 11(c) shows the cycle performance of a three-layer thin-film half-cell, and Figure 11(d) shows the voltage profile of a three-layer thin-film half-cell. The current density was 0.02 mA / cm² for the first three cycles. 2 And then 0.06 mA / cm². 2 In Figure 11, "Cap" = volume.

[0174] LVO-Si-LVO sandwich structures were fabricated by electron beam evaporation. Using V2O5 and Si targets, a V2O5-Si-V2O5 structure was initially formed on a copper substrate, with thicknesses of approximately 300 nm and 200 nm for the V2O5 and Si layers, respectively. This structure was directly used as an electrode paired with a lithium counter electrode. During the first cycle, V2O5 was first lithified to form Li3V2O5, which was then further lithified along with the lithification of Si. Alternatively, or even further, the lithification of V2O5 can also be achieved chemically by reacting it with a lithifying agent such as butyllithium.

[0175] In one experiment, a basic Si thin film was tested in a Li|| thin film cell. The results are shown in Figure 11(a, b). As shown in Figure 11(a, b), in the initial discharge, the Si thin film exhibited a specific capacitance of over 3300 mA·h / g at an average voltage of approximately 0.2 V, which is approximately 0.19 mA·h / cm². 2 This corresponds to the anode area capacitance. However, due to a large irreversible capacitance, after three formation cycles, the specific capacitance of the remaining Si was only 1600 mA·h / g. The capacitance retention rate of the cell was approximately 36% after 100 cycles, which is 0.08 mA·h / cm².2 This corresponds to the anode area capacitance. As shown in Figure 11(b), rapid capacitance decay is also observed in the voltage profile. As illustrated, the discharge plateau shortened and transitioned continuously downward. One plausible explanation for this phenomenon is that the parasitic reaction products not only decrease the cell capacitance but also increase the cell's resistance.

[0176] In comparison, a three-layer film was also tested in a Li thin-film cell. The three-layer film is LVO-Si-LVO on a Cu substrate. As shown in Figure 11(c, d), there is irreversible capacitance after the first discharge, reducing the specific capacitance based on the total weight of the composite from 790 mA·h / g to 510 mA·h / g. As observed in the voltage profile of the first discharge in Figure 11(d), there are several short voltage plateaus between 2.5V and 0.5V, which correspond to the lithiation of V2O5. Therefore, the irreversible capacitance would originate from both Si and V2O5. As shown in Figure 11(d), starting from the first charge, the voltage profile was very smooth between 0.01V and 2V due to the mixed lithiation process of Si and V2O5. According to Figure 11(c), 0.16 mA·h / cm 2 A highly reversible area capacitance was observed, which is twice the capacitance of a Si thin-film anode of the same thickness. More importantly, starting from the fourth cycle, the cell maintained approximately 100% of its capacitance after 100 cycles. The three-layer cyclability demonstrates that LVO protection improves the cycle lifetime of Si-based anodes.

[0177] Figure 11 shows that the specific capacity and cycle rate of the LVO-Si-LVO sandwich structure are comparable to those of an unprotected 200 nm silicon film deposited on Cu. More specifically, Figure 11 shows that the unprotected silicon film undergoes gradual capacity decay with repeated cycles. In stark contrast, the LVO-Si-LVO sandwich structure exhibits essentially perfect capacity retention. In this type of half-cell test, the difference indicates that the LVO helps to cope with the volume expansion of Si and maintain electrical contact.

[0178] Figure 12 shows a photographic image of a decomposed Si thin-film cell after 100 cycles. After 100 cycles, the cell was decomposed and the morphology of the Si thin film was examined. As illustrated in Figure 12, the Si film was completely detached from the Cu substrate and did not maintain its bonding. The Si thin film showed a rapid decline in electrochemical behavior as an anode, as well as mechanical failure. The LVO-Si-LVO sandwich structure is superior to the Si thin film.

[0179] Example 4: Calendar life test of cells at high temperatures. The experiment was conducted to test the calendar lifetime at high temperatures. Figure 13 shows a graph illustrating the cycle repetitions and calendar tests for Si compared to the LVO-Si-LVO thin film structure. The same cell configuration as in Example 3 was used.

[0180] Figure 13(a) shows the cycle repeatability of the Si thin film. Figure 13(b) shows the voltage profile of the Si thin film. Figure 13(c) shows the cycle repeatability of the LVO-Si-LVO3 thin film half-cell. Figure 13(d) shows the voltage profile of the LVO-Si-LVO3 thin film half-cell. The cell was tested in a discharged state at 55°C for 24 hours for calendar lifetime testing, and after cooling, the cell was charged at room temperature. The current density was 0.02 mA / cm² during the first three cycles. 2 And then 0.06 mA / cm². 2 That was the case.

[0181] After three formation cycles at a low current density, the cell was cycled again at C / 5. After the fifth discharge, the cell was disconnected from the battery tester and left to stand at a high temperature of 55°C for 24 hours, followed by a cooling process for approximately one hour. The cell was returned to the battery tester and the fifth charging process was started. The same process was repeated one more time before placing the cell into a normal cycle.

[0182] As illustrated in Figures 13(a, b), the Li||Si thin-film cell started with a discharge specific capacitance exceeding 2000 mA·h / g after the fifth discharge. However, after the settling process, only a specific capacitance of approximately 1000 mA·h / g remained, resulting in a Coulomb efficiency of less than 50%. The same data was reproduced in the sixth cycle, followed by a series of capacitance decay cycles. Furthermore, as illustrated in Figure 13(b), the voltage profiles for the fifth and sixth charges showed an open-circuit voltage (OCV) exceeding 0.6V before charging in some experiments. In the discharge state, the potential of the Si anode is considered to be the same as that of the Li metal, which means a minimum amount of self-discharge between the cathode and anode. Both the increase in OCV and the decrease in Coulomb efficiency suggest that the reaction between the anode and electrolyte significantly affects the calendar lifetime of the Si-based anode.

[0183] As illustrated in Figure 13(c,d), the three-layer thin-film Li cell showed significantly improved calendar lifetime performance. With LVO protection, the cell exhibited a reversible specific capacitance of approximately 520 mA·h / g after three formation cycles. After a high-temperature static process, the Coulomb efficiency was 86% and 87% for the fifth and sixth cycles, respectively—a remarkable improvement over the basic Si thin-film cell. Furthermore, there was no capacitance decay in later cycles, and even a slight capacitance recovery. The OCV at the beginning of the fifth and sixth charge cycles was approximately 0.4V, meaning that a minimum amount of Li ions were lost from the anode.

[0184] As Figure 13 demonstrates, the benefits of LVO protection can be even more apparent in high-temperature storage tests. For example, in the test described in Figure 13, in the 6th and 7th cycles, Si was stored at 55°C for 24 hours in its fully lithified state, after which its delithiation capacity was measured. As illustrated, in the test of this embodiment, the Coulomb efficiency drops from a constant 98% to 45%, which is a significant drop. Since the cell was kept open during the storage period of the test of this embodiment, the capacity loss was not a result of periodic volume changes during the repetition of cycles. More precisely, there was a significant decrease in lithium raw material due to leakage through the SEI layer. The reversible capacity of Si did not fully recover after complete lithiation in subsequent cycles, but the decrease was relatively small compared to the loss of active lithium during high-temperature storage. The test of the embodiment illustrated in Figure 13 demonstrates a challenge related to SEI on the Si anode, which does not appear to be due to passivation by graphite. In contrast, the cycle repeatability and storage behavior of the LVO-Si-LVO sandwich structure was much better than that of the Li||Si thin-film cell. With the LVO mediating layer, the Coulomb efficiency only dropped from 99% to 90% after 24 hours of storage at 55°C in a fully lithium-ion state—a striking contrast to unprotected Si. Note that this was a demanding test given the very high area-to-volume ratio considering the thin-film design.

[0185] A comparison between the example tests illustrated in Figure 13 demonstrates that LVO is a highly effective protective layer for Si during high-temperature storage, which is an excellent indicator of the calendar life of the battery.

[0186] Example 5: Calendar life test of cells at room temperature. To further elucidate the calendar lifetime, more example tests were conducted at room temperature (approximately 25°C) to verify the function of the LVO layer. The results of these tests are shown in Figure 14. Figure 14(a) shows the cycle repeatability of the Si thin film. Figure 14(b) shows the cycle repeatability of the LVO-Si-LVO 3-layer thin film half-cell. The cell was left undisturbed at room temperature for 24 hours in a discharged state. The current density was 0.02 mA / cm² during the first three cycles. 2 And then 0.06 mA / cm². 2 That was the case.

[0187] In these tests, the area capacity of the charge and discharge during the first three formation cycles was approximately 0.14 mA·h / cm². 2 However, starting from the fourth cycle, the area capacity was only about 0.05 mA·h / cm². 2 Capacity was supplied. A large capacity may indicate insufficient kinetics of the Si thin film. This implication is consistent with the data shown in Figure 11. As explained in Figure 14(a), each cycle test consisted of repeating 10 cycles and standing for 24 hours in a discharged state, which showed clear trends in both Coulomb efficiency and capacity retention. Despite the rapid capacity decay in non-standing cycles, the average Coulomb efficiency in standing cycles was approximately 92%, which in some cases resulted from extreme parasitic reactions. In these tests, after 53 cycles, it was only 0.03 mA·h / cm 2 The area volume remained.

[0188] The same calendar lifetime test method was applied to the LVO-Si-LVO3 layer. As shown in Figure 14(b), the first three formation cycles yielded a rate of 0.13 mA·h / cm². 2 This results in an area capacitance of 0.09 mA·h / cm² in the fourth cycle due to the increase in current density. 2 The capacity decreased to less than 30%. By comparison, the single Si thin-film cell lost more than 65% of its capacity after 4 cycles. Here, the average Coulomb efficiency after every 10 cycles of standing cycle was approximately 96%, showing a significant improvement over the Si thin-film cell. After 53 cycles, it was 0.08 mA·h / cm².2 This indicates that there is remaining capacity, signifying a highly reversible system.

[0189] Examples 4 and 5 demonstrate improved calendar lifetime when introducing an LVO layer at both high temperature and room temperature.

[0190] Example 6: SEM analysis of decomposed, cycle-repeated cells. According to the above example, it was experimentally observed that there was almost no capacitance loss in the LVO-Si-LVO3 layer cell after a number of cycles. For further investigation, SEM was performed on the decomposed, cycled cells. Figure 15 shows a series of SEM and XRD images taken from the example experiment. Figure 15(a) shows an SEM image of the top surface of the LVO-Si-LVO3 layer cell after a number of cycles. Figure 15(b) shows an SEM image of the inclined cross-section of the LVO-Si-LVO3 layer cell after a number of cycles. Figure 15(c) shows an SEM image of the cross-section of the LVO-Si-LVO3 layer cell after a number of cycles. Figure 15(d) shows the EDX map of the LVO-Si-LVO3 layer cell after a number of cycles, where the EDX map corresponds to the SEM image in Figure 15(c).

[0191] As illustrated in Figure 15, the three-layer film wrinkled and partially delaminated from the Cu substrate after numerous cycles. These observations can provide evidence of the cause of capacity decay. For example, the EDX mapping in Figure 15(c,d) clearly shows the three-layer structure of the cycled film, meaning that the three films adhered well together while delaminating from the substrate. This observation suggests that Li is confined to a physical barrier. x This supports the V2O5 (3 ≤ x ≤ 5) function. If the volume expansion causing abscission can be completely eliminated, the repeating behavior of the cycle can be further enhanced.

[0192] In this detailed description, several embodiments and accompanying drawings are referenced, in which specific typical embodiments of the art are illustrated by example. These embodiments are described in sufficient detail so that those skilled in the art can practice the art, and it should be understood that those skilled in the art can make improvements to the various disclosed embodiments.

[0193] If the above methods and processes describe specific events occurring in a specific order, those skilled in the art will recognize that the ordering of the specific processes can be improved, and such improvements conform to other forms of the art. Furthermore, the specific processes can be performed simultaneously in parallel processes where possible, and sequentially.

[0194] All publications, patents, and patent applications cited herein are incorporated herein by reference in whole, as if each publication, patent, or patent application were specifically and individually referred to herein.

[0195] The embodiments, alternative forms, and drawings described above should demonstrate the practicality and versatility of the present technology. Other embodiments that do not provide all of the features and advantages described herein can also be used without departing from the spirit and scope of the technology. Such improvements and alternative forms are considered to be within the scope of the technology as defined by the claims.

[0196] While various embodiments of the disclosed technology have been described above, it should be understood that they are shown only as examples and not limiting. Similarly, various diagrams may represent constructive or other forms of embodiments of the disclosed technology and are shown to help understand the features and functionalities that may be included in the disclosed technology. The disclosed technology is not limited to the structures or forms of the exemplary embodiments, but various alternative structures and forms may be used to introduce desired features. It will be obvious to those skilled in the art that alternative functionalities, logical or physical divisions and forms may be introduced to introduce desired features of the technology disclosed herein. Furthermore, with respect to flowcharts, the operational descriptions and methods, and the order in which steps are shown herein, do not imply that various embodiments should be performed in the same order as described functions unless the context otherwise indicates.

[0197] While the disclosed technology is described using various typical embodiments and manifestations, it should be understood that the various features, aspects, and functionalities described in one or more of the individual embodiments are not limited to the specific embodiment in which they are described, but rather, whether such features are shown as part of the described embodiment or not, they can be applied individually or in various combinations to one or more other embodiments of the disclosed technology. Accordingly, the breadth and scope of the technology disclosed herein should not be limited by any of the typical embodiments described above. As will become apparent to those skilled in the art after reading this patent application, the exemplary embodiments and various substitutes therefor can be introduced and are not limited to the exemplary embodiments.

Claims

1. (a) A porous anode phase containing silicon, wherein the porous phase is characterized by a porous volume porosity selected from 5% to 80%, (b) A first solid medium layer disposed outside on the porous anode phase, the first solid medium layer containing a vanadium lithium oxide material, the vanadium lithium oxide material having a density of 2.0 g / cm ３ to 4.5 g / cm ３ , the vanadium lithium oxide material having a composition given by Li ａ V ｂ O ｃ (where a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are selected to balance the charge of the Li ａ V ｂ O ｃ ), and the Li ａ V ｂ O ｃ being capable of being reversibly lithiated, a first solid medium layer; An anode material wherein the thickness of the porous anode phase is 100 nm or more and 100 μm or less.

2. The anode material according to claim 1, wherein the first solid mediating layer forms a shell that encloses the porous anode phase.

3. An anode material which is a sandwiched material in which the first solid mediating layer is disposed outward on the first surface of the porous anode phase and the second solid mediating layer is disposed outward on the second surface of the porous anode phase, wherein the second solid mediating layer contains the vanadium lithium oxide material, according to claim 1.

4. The Li ａ V ｂ O ｃ It exists in a pre-lithiumized state, and the Li ａ V ｂ O ｃ The anode material according to any one of claims 1 to 3, wherein a = 0.

5. The Li ａ V ｂ O ｃ It exists in a lithium state, and the Li ａ V ｂ O ｃ The anode material according to any one of claims 1 to 3, wherein a > 0.

6. The Li ａ V ｂ O ｃ However, Li ３ V ２ O ５ Li ４ V ２ O ５ Li ５ V ２ O ５ LiVO ２ LiV ２ O ５ Li ２ V ２ O ５ LiVO ３ LiV ３ O ８ Li ２ V ３ O ８ Li ３ V ３ O ８ LiV ２ O ３ Li ２ V ２ O ３ Li ３ V ２ O ３ The anode material according to claim 5, selected from the group consisting of the anode material, and combinations thereof.

7. The Li ａ V ｂ O ｃ The anode material according to any one of claims 1 to 6, wherein the material is crystalline.

8. The Li ａ V ｂ O ｃ At least 50% by weight of [Math 1] An anode material according to any one of claims 1 to 7, having an irregular rock salt structure in space groups.

9. The Li ａ V ｂ O ｃ At least 90% by weight of [Math 2] The anode material according to claim 8, having an irregular rock salt structure in the space group.

10. The first solid mediating layer further contains a dopant M which is chemically or physically contained in the lithium vanadium oxide material, and its composition is Li ａ V ｂ O ｃ M ｄ (In the formula, d = 0.1 to 3, and a, b, c, and d are the Li ａ V ｂ O ｃ M ｄ The charge of the Li is given by (selected to equilibrium the charge of the Li ａ V ｂ O ｃ M ｄ The anode material according to any one of claims 1 to 9, which can be reversibly lithium-ized.

11. The anode material according to claim 10, wherein the dopant M is selected from the group consisting of Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof.

12. The Li ａ V ｂ O ｃ M ｄ At least 50% by weight of [Math 3] The anode material according to claim 10, having an irregular rock salt structure in space groups.

13. The anode material according to any one of claims 1 to 12, wherein the porosity of the porous phase volume is selected from 20% to 60%.

14. The anode material according to any one of claims 1 to 13, wherein the silicon is present in the porous anode phase at a concentration of 1% to 100% by weight of Si.

15. The anode material according to any one of claims 1 to 14, wherein the silicon is amorphous silicon.

16. The anode material according to any one of claims 1 to 14, wherein the silicon is polycrystalline silicon.

17. The anode material according to any one of claims 1 to 14, wherein the silicon is single-crystal silicon.

18. The anode material according to any one of claims 1 to 17, wherein the silicon has an average particle size of 10 nanometers to 100 microns.

19. The anode material according to any one of claims 1 to 18, wherein the silicon exists as particles having a geometric shape selected from the group consisting of spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

20. The anode material according to any one of claims 1 to 19, wherein the porous anode phase further contains carbon.

21. The anode material according to claim 20, wherein the carbon is selected from the group consisting of graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

22. The anode material according to any one of claims 1 to 21, wherein the anode material is present in the anode.

23. The anode material according to claim 22, wherein the anode further contains graphite, non-graphitized carbon, silicon dioxide, tin, tin oxide, or a combination thereof.

24. The anode material according to claim 22, wherein the anode further contains one or more binders, and the binders are optionally selected from the group consisting of carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof.

25. The anode is present within the cell, and the cell further includes a cathode, and the cathode is LiFePO ４ , LiMn ２ O ４ , LiNi ０．５ Mn １．５ O ４ , LiNi ｘ Co ｙ Mn ｚ O ２ (x + y + z = 1), LiCoO ２ , LiNi ｘ Co ｙ Al ｚ O ２ (x + y + z = 1), LiFe ｘ Mn ｙ PO ４ (x + y = 1), aLiNi ｘ Co ｙ Mn ｚ O ２ ·(1 - a)Li ２ MnO ３ (a = 0 to 1 and x + y + z = 1), and the anode material according to claim 22, comprising a cathode material selected from the group consisting of combinations thereof.

26. (a) A porous anode phase comprising a silicon-carbon composite containing silicon and carbon, wherein the porous anode phase is characterized by a porous phase volume porosity selected from 5% to 80%, (b) A first solid mediating layer disposed on the outer side of the porous anode phase, wherein the first solid mediating layer contains a lithium vanadium oxide material, and the amount of the lithium vanadium oxide material is 2.0 g / cm³ ３ ~4.5 g / cm ３ The density is such that the vanadium lithium material is Li ａ V ｂ O ｃ (In the formula, a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are the Li ａ V ｂ O ｃ Having a composition given by (selected to equilibrium the charge of Li ａ V ｂ O ｃ However, it includes a first solid mediating layer that can be reversibly lithium-ionized, An anode material wherein the thickness of the porous anode phase is 100 nm or more and 100 μm or less.

27. The anode material according to claim 26, wherein the anode material is a core-shell material in which the first solid mediating layer forms a shell that encloses the porous anode phase.

28. An anode material which is a sandwiched material in which the first solid mediating layer is disposed outward on the first surface of the porous anode phase and the second solid mediating layer is disposed outward on the second surface of the porous anode phase, wherein the second solid mediating layer contains the vanadium lithium oxide material, according to claim 26.

29. The anode material according to any one of claims 26 to 28, wherein the porosity of the porous phase volume is selected from 20% to 60%.

30. The anode material according to any one of claims 26 to 29, wherein the silicon is present in the porous anode phase at a concentration of 1% to 99.9% by weight of Si.

31. The anode material according to any one of claims 26 to 30, wherein the carbon is present in the porous anode phase at a concentration of 0.1% to 80% by weight.

32. The anode material according to any one of claims 26 to 31, wherein the silicon has an average particle size of 10 nanometers to 100 microns.

33. The anode material according to any one of claims 26 to 32, wherein the silicon exists as particles having a geometric shape selected from the group consisting of spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

34. The anode material according to any one of claims 26 to 33, wherein the carbon is selected from the group consisting of graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

35. The Li ａ V ｂ O ｃ It exists in a pre-lithiumized state, and the Li ａ V ｂ O ｃ The anode material according to any one of claims 26 to 34, wherein a = 0.

36. The Li ａ V ｂ O ｃ It exists in a lithium state, and the Li ａ V ｂ O ｃ The anode material according to any one of claims 26 to 34, wherein a > 0.

37. The Li ａ V ｂ O ｃ However, Li ３ V ２ O ５ Li ４ V ２ O ５ Li ５ V ２ O ５ LiVO ２ LiV ２ O ５ Li ２ V ２ O ５ LiVO ３ LiV ３ O ８ Li ２ V ３ O ８ Li ３ V ３ O ８ LiV ２ O ３ Li ２ V ２ O ３ Li ３ V ２ O ３ The anode material according to claim 36, selected from the group consisting of the anode material, and combinations thereof.

38. The Li ａ V ｂ O ｃ The anode material according to any one of claims 26 to 37, wherein the material is crystalline.

39. The Li ａ V ｂ O ｃ At least 50% by weight of [Math 4] An anode material according to any one of claims 26 to 38, having an irregular rock salt structure in space groups.

40. The Li ａ V ｂ O ｃ At least 90% by weight of [Math 5] The anode material according to claim 39, having an irregular rock salt structure in space groups.

41. The first solid mediating layer further contains a dopant M which is chemically or physically contained in the lithium vanadium oxide material, and its composition is Li ａ V ｂ O ｃ M ｄ (In the formula, d = 0.1 to 3, and a, b, c, and d are the Li ａ V ｂ O ｃ M ｄ The charge of the Li is given by (selected to equilibrium the charge of the Li ａ V ｂ O ｃ M ｄ The anode material according to any one of claims 26 to 40, which can be reversibly lithium-ized.

42. The anode material according to claim 41, wherein the dopant M is selected from the group consisting of Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof.

43. The Li ａ V ｂ O ｃ M ｄ At least 50% by weight of [Math 6] The anode material according to claim 41, having an irregular rock salt structure in space groups.

44. The anode material according to any one of claims 26 to 43, wherein the anode material is present in the anode.

45. The anode material according to claim 44, wherein the anode further contains graphite, non-graphitized carbon, silicon dioxide, tin, tin oxide, or a combination thereof.

46. The anode material according to claim 44, wherein the anode further contains one or more binders present in the anode at a concentration of 0.1% to 50% by weight.

47. The anode material according to claim 46, wherein the binder is optionally selected from the group consisting of carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof.

48. The anode material according to claim 44, wherein the anode has an average anode thickness of 200 nanometers to 200 microns.

49. The anode material according to any one of claims 26 to 48, wherein the anode is located within a cell, and the cell further comprises a cathode.

50. The cathode is LiFePO ４ LiMn ２ O ４ LiNi ０．５ Mn １．５ O ４ LiNi ｘ Co ｙ Mn ｚ O ２ (x+y+z=1), LiCoO ２ LiNi ｘ Co ｙ Al ｚ O ２ (x+y+z=1), LiFe ｘ Mn ｙ PO ４ (x+y=1), aLiNi ｘ Co ｙ Mn ｚ O ２ (1-a)Li ２ MnO ３ The anode material according to claim 49, comprising a cathode material selected from the group consisting of (a = 0 to 1 and x + y + z = 1) and combinations thereof.

51. (i) To provide a starting silicon-carbon composite containing silicon and carbon, (ii) Blending the starting silicon-carbon composite with a thermoplastic polymer having a melting point of 300°C or less to produce a silicon-carbon-polymer composite, (iii) The silicon-carbon-polymer composite is solution-coated with a sol-gel solution containing vanadium oxide, thereby producing a silicon-carbon-polymer-vanadium oxide composite, (iv) Heat-treating the silicon-carbon-polymer-vanadium oxide composite at an effective temperature for decomposing and / or vaporizing the thermoplastic polymer, thereby generating a porous anode phase enclosed by a shell containing crystallized vanadium oxide, (v) The crystallized vanadium oxide is chemically lithified with a lithium-containing reducing agent, thereby Li ａ V ｂ O ｃ To produce a lithium vanadium oxide material having a composition given by (wherein a = 0 to 10, b = 1 to 3, c = 1 to 9, and a, b, and c are selected to equilibrium the charge of LiaVbOc), (vi) recovering the anode material containing the porous anode phase encapsulated by the lithium vanadium oxide material, A method for producing an anode material in which the thickness of the porous anode phase is 100 nm or more and 100 μm or less.

52. The method according to claim 51, wherein the porous anode phase is characterized by a volume porosity selected from 5% to 80%.

53. The method according to claim 52, wherein the volumetric porosity is selected from 20% to 60%.

54. The method according to any one of claims 51 to 53, wherein the silicon exists as particles having a geometric shape selected from the group consisting of spheres, columns, cubes, cylinders, tubes, wires, sheets, fibers, irregular shapes, and combinations thereof.

55. The method according to any one of claims 51 to 54, wherein the carbon is selected from the group consisting of graphite, graphene, carbon nanotubes, carbon black, vapor-grown carbon fibers, ultrafine carbon, and combinations thereof.

56. The vanadium oxide in the sol-gel solution ２ O ５ The method according to any one of claims 51 to 55.

57. The method according to any one of claims 51 to 56, wherein the thermoplastic polymer is polylactide (PLA).

58. The method according to any one of claims 51 to 57, wherein the effective temperature in step (iv) is selected from 200°C to 500°C.

59. The method according to claim 58, wherein the effective temperature in step (iv) is selected from 300°C to 400°C.

60. The lithium-containing reducing agent is butyllithium (LiC ４ H ９ ), lithium naphthalene (LiC １０ H ８ ), lithium anthracenate (LiC １４ H ９ The method according to any one of claims 51 to 59, selected from the group consisting of ), and combinations thereof.

61. The Li ａ V ｂ O ｃ However, Li ３ V ２ O ５ Li ４ V ２ O ５ Li ５ V ２ O ５ LiVO ２ LiV ２ O ５ Li ２ V ２ O ５ LiVO ３ LiV ３ O ８ Li ２ V ３ O ８ Li ３ V ３ O ８ LiV ２ O ３ Li ２ V ２ O ３ Li ３ V ２ O ３ The method according to any one of claims 51 to 60, selected from the group consisting of the and combinations thereof.

62. The Li ａ V ｂ O ｃ At least 50% by weight of [Number 7] The method according to any one of claims 51 to 61, having an irregular rock salt structure in the space group.

63. The Li ａ V ｂ O ｃ At least 90% by weight of [Number 8] The method according to claim 62, wherein the space group has an irregular rock salt structure.

64. The aforementioned lithium vanadium oxide material is 2.0 g / cm³ ３ ~4.5 g / cm ３ The method according to any one of claims 51 to 63, having the density of

65. The method further comprises adding dopant M to the vanadium lithium oxide material, wherein the composition is Li ａ V ｂ O ｃ M ｄ (d = 0.1 to 3, and a, b, c, and d are the Li ａ V ｂ O ｃ M ｄ The method according to any one of claims 51 to 64, wherein the charge is provided by (selected to equilibrium the charge of).

66. The method according to claim 65, wherein the dopant M is selected from the group consisting of Be, Mg, Ca, Zn, Fe, Cu, Sc, B, Y, Al, La, Si, Ge, Sn, Ti, Zr, Mn, P, Nb, Ta, Cr, Mo, W, Se, and combinations thereof.

67. The Li ａ V ｂ O ｃ M ｄ At least 50% by weight of [Number 9] The method according to claim 65, wherein the space group has an irregular rock salt structure.

68. The method according to claim 51, further comprising introducing one or more additives selected from the group consisting of graphite, non-graphitized carbon, silicon dioxide, tin, tin oxide, or combinations thereof, into the anode material.

69. The method according to claim 51, further comprising introducing one or more binders selected from the group consisting of carboxymethylcellulose, styrene-butadiene rubber, styrene-butadiene copolymer, polyvinylidene fluoride, and combinations thereof into the anode material.

70. The method according to any one of claims 51 to 69, further comprising: casting the anode material onto a first substrate to form an anode; laminating an electrolyte-containing separator onto the anode; casting a cathode material onto a second substrate to form a cathode; laminating the cathode onto the separator; and surrounding the anode, the separator, and the cathode with a current collector to form a cell.

71. The method according to claim 70, wherein the electrolyte is selected from the group consisting of liquid electrolytes, polymer gel electrolytes, and combinations thereof.

72. The method according to claim 70, wherein the lithium vanadium oxide material is impermeable to the electrolyte.

73. The anode is 0.2 mg / cm³ ２ ~50 mg / cm ２ The method according to claim 70, having an anode material composition amount selected from.

74. The anode has a current of 0.05 mA / h / cm². ２ ~10mA・h / cm ２ The method according to claim 70, having an area capacity of at least one face of the anode selected from.

75. The anode has a current of 0.05 mA / h / cm². ２ ~10mA・h / cm ２ The method according to claim 70, wherein the anode has area capacities on both sides selected from.

76. The method according to claim 70, wherein the anode has an anode thickness selected from 200 nanometers to 200 microns.

77. The method according to claim 70, wherein the cell undergoes at least one charge-discharge cycle, and the lithium vanadium oxide material has a volume change of 0% to 20% during the at least one charge-discharge cycle.

78. The cell is repeatedly charged and discharged over multiple charge-discharge cycles, and the Li ａ V ｂ O ｃ The method according to claim 70, wherein the material is reversibly lithified and delithified multiple times.

79. The method according to claim 78, wherein the cell is charged and discharged for at least 1,000 cycles.

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