Systems and methods for rechargeable energy source systems with redox active positive electrodes

Abstract

In some aspects, the present disclosure provides a rechargeable energy source system. The system can comprise a positive electrode comprising a redox material and having a specific capacity of at least 300 mAh / g. The system can comprise a negative electrode comprising a layer of lithium metal, having a purity level greater than about 90% and a thickness ranging from about 1 μm to about 20 μm. The positive electrode can be configured to maintain a specific capacity for at least 100 charge / discharge cycles between 1.6 and 4.5 Volts at a charge / discharge rate of C / 10 or higher.

Description

SYSTEMS AND METHODS FOR RECHARGEABLE ENERGY SOURCE SYSTEMS WITH REDOX ACTIVE POSITIVE ELECTRODESCROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 517,553, filed August 3, 2023, which application is incorporated herein by reference in its entirety.BACKGROUND

[0002] Large-scale implementation of renewable energy, increasing ubiquity of portable electronics, and the next generation of electric vehicles create additional needs for advanced energy storage systems for transportation, commercial, industrial, residential, and consumer applications.SUMMARY

[0003] In some aspects, the present disclosure provides a rechargeable energy source system comprising: a positive electrode comprising a redox material and having a specific capacity of at least 300 mAh / g; and a negative electrode comprising a layer of lithium metal, said layer of lithium metal having a purity level greater than about 90%.

[0004] In some aspects, the present disclosure provides a rechargeable energy source system comprising: a positive electrode comprising a redox material having a specific capacity of at least 300 mAh / g; and a negative electrode comprising a layer of lithium metal, said layer of lithium metal having a thickness ranging from about 1 pm to about 20 pm.

[0005] In some aspects, the present disclosure provides a rechargeable energy source system comprising: a positive electrode comprising a redox material; and a negative electrode comprising a layer of lithium metal, said layer of lithium metal having an impurity level of less than about 100 ppm by mass; wherein said positive electrode is configured to maintain a specific capacity for at least 100 charge / discharge cycles between 1.6 and 4.5 Volts at a charge / discharge rate of C / 10 or higher.

[0006] In some embodiments, the positive electrode is configured to maintain the specific capacity for at least 100 charge / discharge cycles at a charge / discharge rate of C / 5 or higher.

[0007] In some embodiments, the redox material is configured to intercalate lithium.

[0008] In some embodiments, the redox material comprises a multielectron intercalating material.

[0009] In some embodiments, the positive electrode comprises at least 70% of the redox material by mass.

[0010] In some embodiments, the positive electrode comprises a polymer binder.

[0011] In some embodiments, the polymer binder comprises a block copolymer.

[0012] In some embodiments, the block copolymer provides a hydrophobic domain on a surface of the positive electrode.

[0013] In some embodiments, the system further comprises a hydrophobic polymer membrane bound to the hydrophobic domain on the surface of the positive electrode.

[0014] In some embodiments, the redox material comprises a transition metal redox material.

[0015] In some embodiments, the transition metal redox material comprises at least one of: vanadium, cobalt, nickel, a cobalt-aluminum alloy, manganese, niobium, molybdenum, technetium, tungsten, rhenium, rhodium, ruthenium, iridium, palladium, or platinum.

[0016] In some embodiments, the redox material comprises a polyatomic anion.

[0017] In some embodiments, the polyatomic anion comprises PO4.

[0018] In some embodiments, the redox material comprises VOPO4.

[0019] In some embodiments, the VOPO4 comprises alpha(I)-VOPO4, alpha(II)-VOPO4, beta-VOPO4, epsilon-VOPO4, delta-VOPCU, omega-VOPC , or gamma-VOPCU.

[0020] In some embodiments, the redox material comprises V2O5.

[0021] In some embodiments, the layer of lithium metal comprises less than 0.1 wt% or at% of nitrogen, oxygen, or both.

[0022] In some embodiments, the layer of lithium metal comprises less than 0.1 wt% or at% of boron.

[0023] In some embodiments, the layer of lithium metal comprises less than 0.1 wt% or at% of magnesium, aluminum, or both.

[0024] In some embodiments, the layer of lithium metal comprises less than 0.1 wt% or at% of non-conductive impurities.

[0025] In some embodiments, the layer of lithium metal comprises less than 0.1 wt% lithium alloys.

[0026] In some embodiments, the layer of lithium metal comprises less than 1 non-lithium subsurface structure / mm3.

[0027] In some embodiments, the layer of lithium metal comprises less than 1 non-lithium crystalline subsurface structures / mm3.INCORPORATION BY REFERENCE

[0028] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent publications and patents or patent applications incorporated by reference contradict thedisclosure contained in the specification, the specification is intended to supersede and / or take precedence over any such contradictory material.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The novel features of the disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings of which:

[0030] FIG. 1A shows a scanning electron microscope (SEM) image of e-VOPCU prior to cycling. FIG. IB shows energy-dispersive X-ray spectroscopy (EDS) images of e-VOPCU prior to cycling.

[0031] FIG. 2A shows cycle versus capacity for Cell A. FIG. 2B shows specific capacity versus voltage for Cell A.

[0032] FIGS. 3A-3D shows the experiment results for Cell B.

[0033] FIGS. 4A-4E shows the experiment results for Cell C.

[0034] FIGS. 5A-5D shows the experiment results for Cell D.DETAILED DESCRIPTION

[0035] In some aspects, the present application provides a rechargeable energy source system. The rechargeable energy source system can comprise a redox material. The redox material can comprise a specific capacity of at least 300 mAh / g. The rechargeable energy source system can comprise a negative electrode comprising a layer of lithium metal. The layer of lithium metal can comprise a purity level greater than about 90% by weight. The layer of layer of lithium metal can comprise a thickness ranging from about 1 pm to about 20 pm. The layer of layer of lithium metal can comprise an impurity level of less than about 100 ppm by mass. The positive electrode can be configured to maintain a specific capacity for at least 100 charge / discharge cycles between 1.6 and 4.5 Volts at a charge / discharge rate of C / 10 or higher. The positive electrode can be configured to maintain the specific capacity for at least 100 charge / discharge cycles at a charge / discharge rate of C / 5 or higher.

[0036] The redox material can be configured to intercalate lithium. The redox material can comprise a multielectron intercalating material. The positive electrode can comprise at least 70% of the redox material by mass. The positive electrode can comprise a polymer binder. The polymer binder can comprise a block copolymer. The block copolymer can provide ahydrophobic domain on a surface of the positive electrode. A hydrophobic polymer membrane can be bound to the hydrophobic domain on the surface of the positive electrode.Negative electrode

[0037] In some embodiments, the negative electrode comprises (1) lithium metal which is the electrochemically active component and (2) a substrate which serves as current lead / collector and as the contact to the external circuit. Lithium metal can be chemically unstable in air, so the contact can be made via another material, e.g., one that is chemically stable in air and in the cell chemistry environment. The another material can be chemically and electrochemically inert so as not to compete with the lithium. In some embodiments, a negative electrode can comprise copper, aluminum, graphite coated copper, nickel, silicon, silver, carbon (e.g., rough-surface carbon, graphene), a lithophilic material, aluminum, gold, a copper alloy (Cu-Zn, Cu-Al, Cu-Sn), or any combination thereof. The negative electrode can comprise a layer of lithium metal deposited thereon. Lithium metal can be deposited on the negative electrode with a thickness of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 pm. Lithium metal can be deposited on the negative electrode with a thickness of at least about 1, 5, 10, 20, 30, 40, 50, 100, 200, 300, 400, or 500 pm. Lithium metal can be deposited on the negative electrode with a thickness of at most about 1, 5, 10, 20, 30, 40, 50, 100, 200, 300, 400, or 500 pm. Lithium metal can comprise a thickness between 1 and 380 pm, between 1 and 370 pm, between 1 and 360 pm, between 1 and 350 pm, between 1 and 340 pm, between 1 and 330 pm, between 1 and 320 pm, between 1 and 310 pm, between 1 and 300 pm, between 1 and 250 pm, between 1 and 200 pm, between 1 and 150 pm, between 1 and 100 pm, between 1 and 90 pm, between 1 and 80 pm, between 1 and 70 pm, between 1 and 60 pm, between 1 and 50 pm, between 1 and 45 pm, between 1 and 40 pm, between 1 and 35 pm, between 1 and 30 pm, between 1 and 25 pm, between 1 and 20 pm, between 1 and 15 pm, between 1 and 10 pm, or between 1 and 5 pm.

[0038] In some embodiments, a lithium metal electrode has a specific capacity of greater than about 3500, 3600, 3700, 3750, or 3800 mAh per gram. In some embodiments, a lithium metal electrode has a specific capacity of less than about 3600, 3700, 3750, or 3800 mAh per gram. The overall capacity of the lithium metal electrode (e.g., in basis of mAh) can be substantially matched with the capacity of the positive electrode. In some embodiments, a lithium metal electrode has a density of between about 0.4 g / cm3and about 0.534 g / cm3. In some embodiments, lithium metal electrode has a density of between about 0.45 g / cm3and about 0.543 g / cm3. In some embodiments, lithium metal electrode has a density of greater than 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, or 0.53 g / cm3. In some embodiments, lithium metal electrode has a density of less than 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, or 0.543 g / cm3.

[0039] In some embodiments, lithium metal electrode can comprise less than 0.1 wt% or at% of nitrogen, oxygen, or both. In some embodiments, a lithium metal electrode can comprise less than 0.1 wt% or at% of boron. In some embodiments, a lithium metal electrode can comprise less than 0.1 wt% or at% of magnesium, aluminum, or both. In some embodiments, a lithium metal electrode can comprise less than 0.1 wt% or at% of non-conductive impurities. In some embodiments, a lithium metal electrode can comprise less than 0.1 wt% lithium alloys. In some embodiments, a lithium metal electrode can comprise less than 1 non-lithium subsurface structure / mm3. In some embodiments, a lithium metal electrode can comprise less than 1 nonlithium crystalline subsurface structure / mm3. Without being bound to a particular theory, it is hypothesized that some impurities in lithium may be capable of forming phases that are distinct from the lithium (e.g., crystallites of LiN3 or another compound or another element) after cycling experiments. Thus, a sample of lithium metal can be analyzed to detect the presence of impurities in the 3D images of the sample which can show structural impurities in lithium metal.

[0040] A sample of lithium metal can be imaged using monochromatic hard X-rays with energies chosen in the 22-25 keV range. X-rays can be generated using a synchotron, which can illuminate the entire sample. The X-ray shadow cast by the sample can be converted into visible light using a scintillator. An optical microscope can magnify the image and convert it into digital format. The sample can be rotated, in fractions of degrees, up to 180 degrees to generate -1000 images of the sample. The shadow images can be converted into cross-sectional slides that is stacked together to render a 3D reconstruction of the sample. The 3D reconstruction can reveal structural impurities, e.g., crystallites.

[0041] Lithium metal can comprise less than 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of a non-metallic element. The ppm can be by mass or by count. The ppm can correspond to a basis used for the instrument to detect the non-metallic element. Lithium metal can comprise less than 5 parts-per-million (ppm) of non-metallic elements. In some embodiments, the lithium metal includes no more than 1 ppm of non-metallic elements by mass. The non-metallic element can be nitrogen, boron, oxygen, carbon, hydrogen, or fluorine. Non-metallic elements can be present as atomic species, or molecular species (e.g., as LisN, OH, lithium-boron compounds, carbonate, or O2). In some embodiments, a non-metallic element may form resistive material on a surface of the lithium metal. For example, LiCOs or LiOH can create resistive losses for a lithium metal electrode. The presence of a non-metallic element can be detected using, for example, inductively coupled plasma optical emission spectroscopy (ICP-OES) or X-ray microtomography. The presence of a non-metallic elements may be detected using focused Ion Beam (FIB) with a secondary ion mass spectrometry (SIMS). The presence of a non-metallicelements may be detected using electron energy loss spectroscopy (EELS), and / or transmission electron microscopy (TEM), by detecting and mapping lithium via the high ionization crosssection of the shallow Li K-edge that is 10-100 times greater than those of other light elements, e.g., O and F.

[0042] Lithium metal can comprise less than 1500 ppm of a trace metal. Lithium metal can comprise less than 1400, 1300, 1200, 1100, 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of a trace metal. Lithium metal can comprise more than 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, or 5000 parts-per-billion (ppb) of a trace metal. The ppb can be by mass or by count. The ppb can correspond to a basis used for the instrument to detect the trace element. The trace metal can be aluminum, barium, calcium, chromium, iron, iridium, magnesium, tungsten, zinc, cobalt, or sodium. In some embodiments, a trace element may form an alloy with lithium. An alloy can reduce the capacity of a lithium metal electrode. Lithium metal can comprise less than 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of aluminum. Lithium metal can comprise less than 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of barium. Lithium metal can comprise less than 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of calcium. Lithium metal can comprise less than 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of chromium.Lithium metal can comprise less than 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of iron. Lithium metal can comprise less than 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of iridium. Lithium metal can comprise less than 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 5,0 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 ppm of magnesium. Lithium metal can comprise less than 23, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of tungsten. Lithium metal can comprise less than 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of zinc. Lithium metal can comprise less than 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of sodium. Lithium metal can comprise less than 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 ppm of cobalt. The presence of trace metals can be detected using, for example, inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0043] A lithium metal electrode can comprise a low density of structural impurities, e.g., subsurface structural impurities. Without being bound to a particular theory, elemental or molecular impurities in lithium metal may form phases which are distinct from the lithium upon cycling. When current traverses through the lithium metal, the lithium metal may be heated. Higher temperature may permit impurities to conduct or diffuse in the lithium metal, which canlead to the formation of more stable phases of impurities in the lithium metal (e.g., crystallites). When such structural impurities (phases which have distinct crystal structures, or which have grain boundaries against lithium metal phases in the lithium metal) begin to form, they may continue to grow. Structural impurities can be detected by 3D techniques, e.g., X-ray tomography. Structural impurities may be present on the surface of lithium metal, or it may be present beneath the surface. The structural impurities can provide sites for dendrite nucleation or growth, and may crack the surrounding lithium metal. In some embodiments, the lithium metal can comprise less than 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 structural impurities / mm3. In some embodiments, the lithium metal can comprise less than 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 5,0 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 ppm of structural impurities by weight.Membrane

[0044] In some embodiments, a membrane may be disposed between the positive electrode and the negative electrode. In some embodiments, the membrane may selectively conduct lithium ions between the positive electrode and the negative electrode. In some embodiments, the membrane may substantially prevent or inhibit the passage organic solvents, anions of lithium salts, water, or a contaminant from being transferred between the negative electrode and the positive electrode. A membrane can comprise a single layer or multiple layers. In some embodiments, a membrane can comprise glass fiber, polyester, polyethylene, polypropylene, polyvinylidene fluoride (“PVDF”), polytetrafluoroethylene (“PTFE”), and a combination thereof. In some embodiments, a membrane can comprise hydrophobic polymers. In some embodiments, a membrane can comprise lithium-ion conductive channels.Electrolyte

[0045] In some embodiments, an electrolyte comprises an aqueous electrolyte. In some embodiments, an electrolyte comprises a non-aqueous electrolyte. In some embodiments, an electrolyte comprises a polymer electrolyte. In some embodiments, an electrolyte comprises an organic electrolyte. In some embodiments, an electrolyte comprises a lithium salt. In some embodiments, an electrolyte comprises an ionic liquid. In some embodiments, an electrolyte comprises a deep eutectic solvent. In some embodiments, an electrolyte can be a catholyte. In some embodiments, an electrolyte can be an anolyte. In some embodiments, an electrolyte can be a catholyte and an anolyte.

[0046] In some embodiments, an electrolyte is anhydrous. In some embodiments, an electrolyte is non-flammable or fire-resistant. In some embodiments, an electrolyte is self-extinguishing. Insome embodiments, an electrolyte comprises additives, e.g., nitrogen, sulfur, phosphorus, or silicon compounds.

[0047] In some embodiments, an electrolyte comprises a decomposition potential of at least 2, 3, 4, 5, or 6 V. In some embodiments, an electrolyte comprises a decomposition potential of at most 2, 3, 4, 5, or 6 V. In some embodiments, an electrolyte comprises a dielectric constant of at least 2, 5, 10, 20, 30, 40, 50, 60, 70, or 80. In some embodiments, an electrolyte comprises a dielectric constant of at most 3, 5, 10, 20, 30, 40, 50, 60, 70, 80, or 90. An electrolyte can comprise various viscosities. Polymeric or polymer solution electrolytes can comprise a large viscosity, as the viscosity can scale exponentially with molecular weight of the polymer above a critical molecular weight (e.g., entanglement molecular weight). In some embodiments, an electrolyte comprises a viscosity of at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, or 900 mPa«s. In some embodiments, an electrolyte comprises a viscosity of at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, or 900 Pa«s. In some embodiments, an electrolyte comprises a viscosity of at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, or 900 kPa«s. In some embodiments, an electrolyte comprises a viscosity of at most 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, or 900 mPa»s. In some embodiments, an electrolyte comprises a viscosity of at most 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, or 900 Pa»s. In some embodiments, an electrolyte comprises a viscosity of at most 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, or 900 kPa«s.

[0048] Various organic electrolytes can be used. In some embodiments, an organic electrolyte can comprise dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, l,3-dioxolan-2-one, 4-methyl-l,3-dioxolan-2-one, oxolan-2-one, and any combination thereof. In some embodiments, an electrolyte can comprise an organic carbonate compound, an ester compound, an ether compound, a ketone compound, an alcohol compound, an aprotic bipolar solvent, or a combination thereof. The carbonate compound may be an open chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate derivative thereof, or a combination thereof.

[0049] In some embodiments, the chain carbonate compound can be diethyl carbonate (“DEC”), dimethyl carbonate, (“DMC”), dipropyl carbonate (“DPC”), methylpropyl carbonate (“MPC”), ethylpropylcarbonate (“EPC”), methylethyl carbonate (“MEC”), and a combination thereof. In some embodiments, the cyclic carbonate compound can be ethylene carbonate (“EC”), propylenecarbonate (“PC”), butylene carbonate (“BC”), fluoroethylene carbonate (“FEC”),vinylethylene carbonate (“VEC”), and a combination thereof. In some embodiments, the fluorocarbonate compound can be fluoroethylene carbonate (“FEC”), 4,5-difluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,4,5-trifluoroethylene carbonate, 4, 4,5,5- tetrafluoroethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4,4,5-trifluoro-5-methylethylene carbonate, trifluoromethylethylene carbonate, and a combination thereof. In some embodiments, the carbonate compound may include a combination of cyclic carbonate and chain carbonate, in consideration of dielectric constant and viscosity of the electrolyte. In some embodiments, the carbonate compound may be a mixture of such chain carbonate and / or cyclic carbonate compounds as described above with a fluorocarbonate compound. In some embodiments, the fluorocarbonate compound may increase solubility of a lithium salt to improve ionic conductivity of the electrolyte, and may facilitate formation of the thin film on the negative electrode. In some embodiments, the ester compound is methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate (“MP”), ethyl propionate, y-butyrolactone, decanolide, valerolactone, mevalonolactone, caprolactone, and methyl formate. In some embodiments, the ether compound is dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxy ethane,1.2-di ethoxy ethane, ethoxymethoxy ethane, 2-m ethyltetrahydrofuran, and tetrahydrofuran. An example of the ketone compound is cyclohexanone. In some embodiments, the alcohol compound can be ethyl alcohol or isopropyl alcohol. In some embodiments, the aprotic solvent can be a nitrile (such as R — CN, wherein R is a C2-C20 linear, branched, or cyclic hydrocarbonbased moiety that may include a double-bond, an aromatic ring or an ether bond), amides (such as formamide and dimethylformamide), dioxolanes (such as 1,2-dioxolane and 1,3-dioxolane), methylsulfoxide, sulfolanes (such as sulfolane and methyl sulfolane), l,3-dimethyl-2- imidazolidinone, N-methyl-2-pyrrolidinone, nitromethane, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and triester phosphate. In some embodiments, an electrolyte can comprise an aromatic hydrocarbon organic solvent in a carbonate solvent. In some embodiments, an aromatic hydrocarbon organic solvent can be benzene, fluorobenzene, 1,2-difluorobenzene,1.3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, chlorobenzene, 1,2-di chlorobenzene, 1,3 -di chlorobenzene, 1,4-di chlorobenzene, 1,2,3- trichlorobenzene, 1, 2, 4-tri chlorobenzene, iodobenzene, 1,2-diiodobenzene, 1,3-diiodobenzene,1.4-diiodobenzene, 1,2, 3 -triiodobenzene, 1,2,4-triiodobenzene, 2-fluorotoluene, 3 -fluorotoluene, 4-fluorotoluene, 2,3-difluorotoluene, 2,4-difluorotoluene, 2,5-difluorotoluene, 2,6- difluorotoluene, 3,4-difluorotoluene, 3, 5 -difluorotoluene, 2,3,4-trifluorotoluene, 2,3,5- trifluorotoluene, 2,3,6-trifluorotoluene, 3,4,5-trifluorotoluene, 2,4, 5 -trifluorotoluene, 2,4,6- trifluorotoluene, 2-chlorotoluene, 3 -chlorotoluene, 4-chlorotoluene, 2,3-dichlorotoluene, 2,4-di chlorotoluene, 2,5-dichlorotoluene, 2,6-dichlorotoluene, 2, 3, 4-tri chlorotoluene, 2,3,5- tri chlorotoluene, 2,3,6-trichlorotoluene, 3,4,5-trichlorotoluene, 2,4,5-trichlorotoluene, 2,4,6- tri chlorotoluene, 2-iodotoluene, 3 -iodotoluene, 4-iodotoluene, 2,3 -diiodotoluene, 2,4- diiodotoluene, 2,5-diiodotoluene, 2,6-diiodotoluene, 3,4-diiodotoluene, 3,5-diiodotoluene, 2,3,4- triiodotoluene, 2,3,5-triiodotoluene, 2,3,6-triiodotoluene, 3,4,5-triiodotoluene, 2,4,5- triiodotoluene, 2,4,6-triiodotoluene, o-xylene, m-xylene, p-xylene, and combinations thereof.

[0050] Various polymeric electrolytes can be used. A polymer electrolyte can comprise polyethylene oxide), poly(vinyl alcohol), poly(methyl methacrylate), poly(caprolactone), poly(chitosan), poly(vinyl pyrrolidone), poly(vinyl chloride), poly(vinyl fluoride), poly(imide), or any combination thereof, which can inherently conduct lithium ions or be doped with one or more lithium salts to make the polymer be lithium conductive.

[0051] Various ionic liquids can be used, e.g., any one of the ionic liquids listed on the Ionic Liquids Database (ILThermo) of the National Institute of Standards and Technology.

[0052] Various lithium salts can be used. A lithium salt can comprise lithium 12- hydroxystearate, lithium acetate, lithium amide, lithium aspartate, lithium azide, lithium bis(trifluoromethanesulfonyl)imide, lithium borohydride, lithium bromide, lithium carbonate, lithium chlorate, lithium chloride, lithium citrate, lithium cyanide, lithium diphenylphosphide, lithium hexafluorogermanate, lithium hexafluorophosphate, lithium hypochlorite, lithium hypofluorite, lithium metaborate, lithium methoxide, lithium naphthalene, lithium niobate, lithium nitrate, lithium nitrite, lithium oxalate, lithium perchlorate, lithium stearate, lithium succinate, lithium sulfate, lithium sulfide, lithium superoxide, lithium tantalate, lithium tetrachloroaluminate, lithium tetrafluorob orate, lithium tetrakis(pentafluorophenyl)borate, lithium triflate, lithium tungstate, or any combination thereof. In some embodiments, an electrolyte can comprise lithium salts comprising an organic anion selected from the group consisting of trifluoromethanesulfonyl-imide (TFSI), N- butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PyruTFSI), trifluoromethanesulfonyl-imide, bis(trifluoromethanesulfonyl)imide (LiTFSI), and l-ethyl-3- methylimidazolium- bis(trifluoromethylsulfonyl)imide (EMLTFSI) . In some embodiments, the catholyte 290 comprises ionic liquid-forming salts dissolved in 1,3-dioxolane (DOL), 1,2 dimethoxyethane (DME), or tetraethylene glycol dimethyl ether (TEGDME). In some embodiments, an electrolyte can comprise Li2SO4, Li2CO3, LiPFe, LiBF4, LiCICU, LiTFSI, and combinations thereof. In some embodiments, an electrolyte can comprise LiPFe, LiBF4, LiSbFe, LiAsFe, LiSbFe, LiCF3SO3, Li(CF3SO2)3C, Li(CF3SO2)2N, LiC4F9SO3, LiClO4, LiA104, LiAICU, LiAlF4, LiBPh4, LiBiOCl, CH3SO3Li, C4F3SO3Li, (CF3SO2)2NLi, LiN(CxF2x+iSO2)(CxF2y+iSO2) (wherein x and y are natural numbers), CFsCCLLi, LiCl, LiBr, Lil, LIBOB (lithium bisoxalato borate), lower aliphaticcarboxylic acid lithium, lithium terphenylborate, lithium imide, and any combination thereof. In some embodiments, a concentration of the lithium salt may be in a range of about 0.1 molar (“M”) to about 2.0 M. In some embodiments, a concentration of the lithium salt is at least 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, or 3 M. In some embodiments, a concentration of the lithium salt is at most 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, or 3 M.Positive electrode

[0053] In some embodiments, a positive electrode comprises a current collector. In some embodiments, a positive electrode comprises an active material. In some embodiments, a positive electrode comprises an active material disposed on a current collector. In some embodiments, a current collector may have a thickness of at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 pm. In some embodiments, a current collector may have a thickness of at most 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 pm. In some embodiments, a current collector comprises copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel that is surface-treated with carbon, nickel, titanium or silver, and aluminum-cadmium alloys In some embodiments, a current collector comprises fine irregularities on surfaces thereof so as to enhance adhesive strength of the positive electrode current collector to the positive electrode active material. In some embodiments, a current collector comprises can comprise various forms including films, sheets, foils, nets, porous structures, foams, and non-woven fabrics. In some embodiments, a current collector comprises carbon, carbon paper, carbon cloth or a metal or noble metal mesh or foil.

[0054] In some embodiments, a positive electrode comprises a surface coating. In some embodiments, a surface coating comprises an oxide, a hydroxide, an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate. In some embodiments, a surface coating is amorphous or crystalline. In some embodiments, a surface coating comprises magnesium (Mg), aluminum (Al), cobalt (Co), potassium (K), sodium (Na), calcium (Ca), silicon (Si), titanium (Ti), vanadium (V), tin (Sn), germanium (Ge), gallium (Ga), boron (B), arsenic (As), zirconium (Zr), or any combination thereof. In some embodiments, a surface coating comprises is formed using a spray coating method, a dipping method, or any other suitable method.

[0055] In some embodiments, a positive electrode comprises a binder. The binder can bind an active material to a current collector. In some embodiments, a binder comprises polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinylchloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer including ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber (“SBR”), acrylated SBR, epoxy resin, and nylon. In some embodiments, a binder is electrically conductive. In some embodiments, a binder comprises carbon black or vapor ground carbon fibers. In some embodiments, a binder comprises polyvinylidene fluoride (PVDF), sodium alginate, and sodium carboxymethyl cellulose. In some embodiments, a binder comprises PVDF, polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), and polyimide. In some embodiments, a binder comprises graphene or carbon nanotubes.

[0056] In some embodiments, a positive electrode comprises an electron intercalating material. In some embodiments, a positive electrode comprises a multi-electron intercalating material. In some embodiments, a positive electrode comprises a transition metal, which undergoes a change in oxidation state of at least two between a charged and discharged state. In some embodiments, a positive electrode comprises titanium disulfide. In some embodiments, a positive electrode comprises a metal oxide. In some embodiments, a positive electrode comprises LixMCh, wherein M is a metal. In some embodiments, a positive electrode comprises vanadium. In some embodiments, a positive electrode comprises vanadium, cobalt, nickel, a cobalt-aluminum alloy, manganese, niobium, molybdenum, technetium, tungsten, rhenium, rhodium, ruthenium, iridium, palladium, or platinum. In some embodiments, a positive electrode comprises a polyatomic anion. In some embodiments, a polyatomic anion comprises PO4.

[0057] In some embodiments, a positive electrode comprises vanadyl. In some embodiments, a positive electrode comprises phosphate. In some embodiments, a positive electrode comprises V2O5. In some embodiments, a positive electrode comprises vanadyl phosphate (VOPO4). In some embodiments, VOPO4 can comprise alpha(I)-VOPO4, alpha(II)-VOPO4, beta-VOPCU, epsilon-VOPO4, delta-VOPC , omega-VOPCU, or gamma-VOPC

[0058] In some embodiments, a positive electrode comprises a sheet, ribbon, particles, or other forms. In some embodiments, a positive electrode comprises microstructures. In some embodiments, a positive electrode comprises nanostructures. The microstructures or the nanostructures can comprise substantially spherical, cylinder, or lamellar morphologies, or any combination thereof.

[0059] In some embodiments, a vanadyl phosphate positive electrode comprises two redox couples of a vanadium cation (V5+ / V4+and V4+ / V3+). In some embodiments, the two redox couples can permit more than one lithium ion to be stored in the unit structure per vanadium ion.

[0060] In some embodiments, a positive electrode comprises additives. In some embodiments, a positive electrode comprises phosphate based materials such as FePC , VPO4F, V2(PO4)2F3,FePCUF, and V2(PO4)3; oxides such as CoO2, V2O5, orthorhombic MnCh, layered iron oxides FeCh, chromium oxide CrCh, layered Nio.5Mno.5O2, and VeOis nanorods; layer sulfides such as TiS2; perovskite transition metal fluorides, or a mixture thereof.

[0061] In some embodiments, a positive electrode comprises S-VOPO4. The epsilon polymorph of vanadyl phosphate, S-VOPO4, can be made from hydrothermally or solvothermally synthesized H2VOPO4. In some embodiments, VOPO4 can be synthesized using carbothermal reduction, ball-milling, micro-wave assisted solvothermal synthesis, exfoliation from sheets, or any combination thereof. In some embodiments, VOPO4 can be annealed.

[0062] In some embodiments, a positive electrode comprises a coulombic efficiency of at least 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, or 99.9% for at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 cycles. In some embodiments, a positive electrode comprises a coulombic efficiency of at most 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, or 100% for at most 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or1000 cycles. In some embodiments, a positive electrode comprising s-VOPCU comprises a coulombic efficiency of at least 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, or 99.9% for at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 cycles. In some embodiments, a positive electrode comprising 8- VOPO4 comprises a coulombic efficiency of at most 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, or 100% for at most 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 cycles. In some embodiments, a cycle can comprise a charge / discharge cycle between 1.6 and 4.5 Volts, 1.6 and 3 Volts, 3 and 4.5 Volts. The voltage can be in reference to a lithium metal. In some embodiments, a cycle can comprise a charge / discharge cycle rate of at least C / 50, C / 20, C / 10 C / 5, C / 4, C / 3, C / 2, C / 1, 2C, 3C, 4C, or 5C. In some embodiments, a cycle can comprise a charge / discharge cycle rate of at most C / 50, C / 20, C / 10 C / 5, C / 4, C / 3, C / 2, C / 1, 2C, 3C, 4C, or 5C.

[0063] In some embodiments, a positive electrode comprises a capacity of at least 275, 280, 290, 300, or 305 mAh / g. In some embodiments, a positive electrode comprises a capacity of at most 275, 280, 290, 300, or 305 mAh / g.

[0064] In some embodiments, a positive electrode comprises s-VOPCU and an electrically conductive filler. In some embodiments, an electrically conductive filler comprises graphene. In some embodiments, a positive electrode comprises s-VOPCU and at least 2.5% by weight electrically conductive filler, at least 3.0% by weight electrically conductive filler, at least 3.5% by weight electrically conductive filler, at least 4.0% by weight electrically conductive filler, at least 5% by weight electrically conductive filler, at least 6% by weight electrically conductivefiller, at least 7% by weight electrically conductive filler, at least 8% by weight electrically conductive filler, at least 9% by weight electrically conductive filler, or at least 10% by weight electrically conductive filler. The positive electrode can comprise, for example, at least 75% by weight S-VOPO4, at least 5% by weight graphene nanoplatelets, and at least 5% by weight of a poly vinylidene fluoride (PVDF) binder. The intercalation electrode composition may comprise 85% by weight s-VOPCU, at least 5% by weight graphene nanoplatelets, and 10% by weight binder. The intercalation electrode composition may comprise 75% by weight s-VOPCU, 15% by weight graphene nano platelets, and 10% by weight of a poly vinylidene fluoride (PVDF) binder.Polymer

[0065] In some embodiments, the lithium conductive polymer comprises a copolymer. In some embodiments, the polymer can comprise a block copolymer or a random copolymer. In some embodiments, a portion of the block copolymer is in contact with lithium metal, wherein the portion is substantially unreactive with the lithium metal. A block copolymer can, for example, be annealed to undergo microphase separation, providing an exposed hydrophobic surface that is substantially unreactive with lithium metal. Meanwhile, the block copolymer can further comprise a percolating hydrophilic domain that provides paths for lithium ions to traverse through from one side of the block copolymer to the other. In some embodiments, the block copolymer comprises diblock copolymer, triblock copolymer, triblock terpolymer, and multiblock copolymer, and grafted copolymer. In some embodiments, the block copolymer can comprise PDMS-PEG (e.g., poly(polydimethylsiloxane)-b-poly(poly(ethylene glycol) methacrylate)). In some embodiments, the block copolymer can comprise POEM-b-PLMA (poly (oxy ethylene methacrylate)-b-poly(lauryl methacrylate)), POEM ((polyoxyethylene methyl methacrylate))-P(PDMSMA (polydimethylsiloxane methacrylate)), PBA-b-PPEGMA, or any combination thereof. In some embodiments, a copolymer can comprise poly(butyl acrylate) (PBA), Poly(butyl methacrylate) (PBMA), Poly(lauryl methacrylate) (PLMA), Poly(ethylene) (PE), Poly(ethylene-alt-propylene) (PEP), Poly(urethane) (PU), Poly(butadiene) (PB), Poly(polyvinylidene methacrylate) (PPVDFMA), Poly (polytetrafluoroethylene methacrylate) (PPTFEMA), Poly(perfluoropolyether) (PFPE), Poly(perfluoropolyether methacrylate) (PFPEMA), Poly(perfluoropolyether acrylate) (PFPEA), Poly(poly(ethylene glycol) methacrylate) (PPEGMA), Poly(poly(ethylene glycol) acrylate) (PPEGA), Poly(perfluoropolyether methacrylate) (PFPEMA), Poly(perfluoropolyether acrylate) (PFPEA), or any combination thereof.

[0066] The hydrophobic polymer can comprise, e.g., a cyclic olefin copolymer, fluorinated ethylene propylene, ethylene-methyl acrylate copolymer, polymonochlorotrifluoroethylene,perfluoroalkoxy polymer, polymethylpentene, polypropylene, polyphenylene sulfide, polystyrene, polytetrafluoroethylene, polyvinylchloride, polyethylene, ethylene vinyl acetate, or any combination thereof.

[0067] While preferred embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. It should be understood that various alternatives to the embodiments of the present disclosure may be employed in practicing the present disclosure. It is intended that the following claims define the scope of the present disclosure and that methods and structures within the scope of these claims and their equivalents be covered thereby.EXAMPLES

[0068] The following examples are provided to further illustrate some embodiments of the present disclosure, but are not intended to limit the scope of the disclosure; it will be understood by their exemplary nature that other procedures, methodologies, or techniques known to those skilled in the art may alternatively be used.Example 1: Cell Construction

[0069] This example describes how to construct an electrochemical cell with e-VOPCU positive electrodes.

[0070] Monoclinic H2VOPO4 precursor is calcined. VCI3 and P2O5 is dissolved in 190 proof ethanol. The solution is placed in a reactor and heated to 180 °C. The reaction is set to proceed for several days. The product is collected by centrifugation and heated to 550 °C under flowing oxygen for several hours to produce e-VOPC

[0071] The e-VOPO4 is chemically lithiated under helium atmosphere at ambient temperature, e- VOPO4 powder is dispersed in hexane and stirred. N-butyllithium is added to the solution, with excess. After several days, the output solid is washed with hexane and collected.

[0072] The solid e-VOPCUis mixed with graphene nanoplatelets, polyvinylidene fluoride, and 1- methyl-2-pyrrolidinone to create a slurry. The slurry is laminated onto an aluminum foil current collector. The laminate is vacuum dried overnight.

[0073] The dried laminate (the positive electrode) is assembled with a pure lithium electrode, about 20 microns thick and less than .1 wt% non-metallic elements, in a glove box purged with Helium. Lithium hexafluorophosphate (LiPFe) in ethylene carbonate / dimethyl carbonate is the electrolyte. Celgard 2400 is the separator. The assembly constitutes the electrochemical cell.Example 2: s-VOPC

[0074] This example provides experiments conducted using electrochemical cells with e-VOPCU positive electrodes. Table 1, shown below, outlines the parameters used in the experiments.Table 1. Experimental parameters for electrochemical cells.

[0075] Samples of VOPO4 were obtained, and experiments were conducted to confirm its morphology and composition. FIG. 1A shows a scanning electron microscope (SEM) image of e-VOPO4 prior to cycling. FIG. IB shows energy-dispersive X-ray spectroscopy (EDS) images of e-VOPO4 prior to cycling. The SEM and EDS experiments show morphology and composition consistent with what is expected for e-VOPCU.

[0076] An electrochemical cell (Cell A) was constructed using 40 pm lithium metal as the negative electrode, e-VOPO4 as the positive electrode, and 1 M LiPFe in EC:DMC (1 : 1) as theelectrolyte. EC refers to ethylene carbonate and DMC refers to dimethyl carbonate. The positive electrode was initially wetted with the electrolyte off of the cycler for above 24 hours. The electrochemical cell was formed by cycling once from 1.6 to 4.5 volts (V) with a symmetrical C- rate of C / 20:C / 20. The temperature was about 23 degrees Celsius (°C). Then, the electrochemical cell was cycled for about 40 days between 1.6-4.5 V with a symmetrical C-rate of C / 5:C / 5.

[0077] FIG. 2A shows cycle versus capacity for Cell A. A noticeable increase in the capacity was observed at about 35 cycles, which may be due to the increase in temperature of the lab environment. FIG. 2B shows specific capacity versus voltage for Cell A. Some capacity losses were noticed, which may be due to polarization on discharge. The maximum specific capacity was about 332.79 mAh / g, and the maximum areal capacity was about 1.01 mAh / cm2No significant capacity fade was subsequently observed for up to 130 cycles.

[0078] Three additional electrochemical cells were constructed (Cells B-D) The cells contained 40 pm lithium metal as the negative electrode, e-VOPCU as the positive electrode, and 1 M LiPFe in EC:DMC (1 : 1) as the electrolyte. Each of Cells B-D were formed by discharging to the target voltage and cycling twice at C / 20:C / 20 within between the cycling voltage range (See Table 1). Each of Cells B-D were then cycled with a series of different C-rates (See Table 1).

[0079] FIGS. 3A-3D shows the experiment results for Cell B.

[0080] FIGS. 4A-4E shows the experiment results for Cell C. Cell C demonstrated a specific capacity of about 125mAh / g. The cell was able to recover its initial C / 5 capacity, even after 2C and 3C cycling. After -110 cycles of C / 2:C / 2, the cell was put through (3) cycles of C / 5:5C cycling (see FIG. 4E, arrow indicator). After 5C discharge, the cell is able to recover and continue cycling at full capacity.

[0081] FIGS. 5A-5D shows the experiment results for Cell D.

[0082] The cells were able to retain capacity with no significant capacity fade, even at high discharge rates such as 2C and 3C. Overall the e-VOPO4 demonstrated excellent rate capabilities with asymmetrical charge / discharge cycles up through C / 5:3C.Example 3: X-ray Microtomography

[0083] This example describes X-ray microtomography experiments for detecting the presence of impurities in lithium metal.

[0084] An electrochemical cell, after cycling experiments, is dissembled to extract a lithium metal negative electrode. Without being bound to a particular theory, it is hypothesized that some impurities in lithium may be capable of forming phases that are distinct from the lithium (e.g., crystallites of LiN3 or another compound or another element) after cycling experiments.Thus, a sample of lithium metal can be analyzed to detect the presence of impurities in the 3D images of the sample which can show structural impurities in lithium metal.

[0085] A sample of lithium metal is imaged using monochromatic hard X-rays with energies chosen in the 22-25 keV range. X-rays can be generated using a synchotron, which can illuminate the entire sample. The X-ray shadow cast by the sample is converted into visible light using a scintillator. An optical microscope magnifies the image and converts it into digital format. The sample is rotated, in fractions of degrees, up to 180 degrees to generate -1000 images of the sample. The shadow images are converted into cross-sectional slides that is stacked together to render a 3D reconstruction of the sample. The 3D reconstruction is able to reveal structural impurities, e.g., crystallites.

Claims

CLAIMSWhat is claimed is:

1. A rechargeable energy source system comprising: a positive electrode comprising a redox material and having a specific capacity of at least 300 mAh / g; and a negative electrode comprising a layer of lithium metal, said layer of lithium metal having a purity level greater than about 90%.

2. A rechargeable energy source system comprising: a positive electrode comprising a redox material having a specific capacity of at least 300 mAh / g; and a negative electrode comprising a layer of lithium metal, said layer of lithium metal having a thickness ranging from about 1 pm to about 20 pm.

3. A rechargeable energy source system comprising: a positive electrode comprising a redox material; and a negative electrode comprising a layer of lithium metal, said layer of lithium metal having an impurity level of less than about 100 ppm by mass; wherein said positive electrode is configured to maintain a specific capacity for at least 100 charge / discharge cycles between 1.6 and 4.5 Volts at a charge / discharge rate of C / 10 or higher.

4. The rechargeable system of claim 3, wherein the positive electrode is configured to maintain the specific capacity for at least 100 charge / discharge cycles at a charge / discharge rate of C / 5 or higher.

5. The rechargeable system of any one of claims 1-4, wherein the redox material is configured to intercalate lithium.

6. The rechargeable system of any one of claims 1-5, wherein the redox material comprises a multielectron intercalating material.

7. The rechargeable system of any one of claims 1-6, wherein the positive electrode comprises at least 70% of the redox material by mass.

8. The rechargeable system of any one of claims 1-7, wherein the positive electrode comprises a polymer binder.

9. The rechargeable system of claim 8, wherein the polymer binder comprises a block copolymer.

10. The rechargeable system of claim 9, wherein the block copolymer provides a hydrophobic domain on a surface of the positive electrode.11 . The rechargeable system of claim 10, further comprising a hydrophobic polymer membrane bound to the hydrophobic domain on the surface of the positive electrode.

12. The rechargeable system of any one of claims 1-11, wherein the redox material comprises a transition metal redox material.

13. The rechargeable system of claim 12, wherein the transition metal redox material comprises at least one of: vanadium, cobalt, nickel, a cobalt-aluminum alloy, manganese, niobium, molybdenum, technetium, tungsten, rhenium, rhodium, ruthenium, iridium, palladium, or platinum.

14. The rechargeable system of any one of claims 1-13, wherein the redox material comprises a polyatomic anion.

15. The rechargeable system of claim 14, wherein the polyatomic anion comprises PO4.

16. The rechargeable system of any one of claims 1-15, wherein the redox material comprises VO PO4.

17. The rechargeable system of claim 16, wherein the VOPO4 comprises alpha(I)-VOPO4, alpha(II)- VOPO4, beta-VOPO4, epsilon-VOPO4, delta-VOPO4, omega-VOPO4, or gamma-V0P04.

18. The rechargeable system of any one of claims 1-15, wherein the redox material comprises V2O5.

19. The rechargeable system of any one of claims 1-18, wherein the layer of lithium metal comprises less than 0. 1 wt% or at% of nitrogen, oxygen, or both.

20. The rechargeable system of any one of claims 1-19, wherein the layer of lithium metal comprises less than 0. 1 wt% or at% of boron.

21. The rechargeable system of any one of claims 1-20, wherein the layer of lithium metal comprises less than 0. 1 wt% or at% of magnesium, aluminum, or both.

22. The rechargeable system of any one of claims 1-21, wherein the layer of lithium metal comprises less than 0. 1 wt% or at% of non-conductive impurities.

23. The rechargeable system of any one of claims 1-22, wherein the layer of lithium metal comprises less than 0. 1 wt% lithium alloys.

24. The rechargeable system of any one of claims 1-23, wherein the layer of lithium metal comprises less than 1 non-lithium subsurface structure per mm3.

25. The rechargeable system of any one of claims 1-24, wherein the layer of lithium metal comprises less than 1 non-lithium crystalline subsurface structure per mm3.

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