Improved anode materials and anodes for rechargeable batteries, methods for manufacturing them, and electrochemical cells made from them.

Abstract

The anode material of the electrochemical cell comprises a matrix material:dispersion material composite, which includes one or more alkali metals and / or alkaline earth metals. The dispersion material may include metals other than the metal of the matrix material, such as transition metals and / or post-transition metals. The anode material may be all or part of an anode for an electrochemical cell and may further include a current collector and / or SEI layer. The electrolyte may include an electrolyte salt of an alkali metal, alkaline earth metal, transition metal, and / or post-transition metal. The matrix material and / or dispersion material may include one or more metals of the electrolyte salt. All or part of the anode can be used as a substrate for electrodeposition of one or more matrix materials during charging and / or as a source of matrix materials during discharge. The electrolyte may further include one or more electrolyte additives. The anode material can be produced by mixing the matrix material and dispersion material and heating to selectively melt the matrix material to produce a matrix material:dispersion material composite. The composite material can be further chemically or mechanically processed to reduce the size of the dispersed material and / or improve the homogeneity of the matrix material:dispersed material composite. The anode material, anode, or electrochemical cell can be used in a device.

Description

Technical Field

[0001] The present invention relates to rechargeable electrochemical battery cells. In particular, the present invention relates to the preparation of electrodes based on metal matrices, enabling battery chemistry improvements in electrochemical cells from the perspectives of cost, lifespan, and energy density.

Background Art

[0002] High-performance, long-life, and low-cost batteries are advantageous for many applications such as electric vehicles and energy storage in power grids.

[0003] In the field of battery technology, intensive research has been conducted to develop batteries operating with electrodeposited metal anodes. Along with lithium, sodium-based metal anodes offer the highest theoretical weight capacity among all anode materials. For example, the weight capacity of sodium exceeds 1100 mAh / g and has a potential of -2.7 V with respect to the standard hydrogen electrode for the Na+ / Na electrode pair. Furthermore, metal anodes do not require solid diffusion of ions to transition the material from a charged state to a discharged state, but only require the success of ion deposition / dissolution on or from the surface of the metal. The resulting metal anodes are volumetrically compact and do not require the electrolyte-filled interparticle (intercalation) spaces in current battery anodes.

[0004] Due to the above technical reasons and the abundance and low cost of sodium, batteries based on sodium metal anodes are particularly highly desirable. However, the high ambient reactivity of alkaline earths, especially alkali metals including metallic sodium and lithium, during the assembly of battery cells has thus far hindered the use of alkali metals, more specifically metallic sodium anodes.

[0005] Another approach is the assembly of battery cells in a discharged state, using air-stable current collectors as substrates for ion electrodeposition. While some publications claim to have identified suitable methods for achieving sodium deposition and cycling with very close to 100% Coulomb efficiency, published studies still suffer from the following major shortcomings: unrealistically expensive electrolyte compositions, unrealistically complex substrate preparations, non-reproducibility of the experimental procedures for published substrate preparations, or non-reproducibility of the Coulomb efficiency data claimed in publications. This is why, to date, there are no corresponding battery fabrications based on metal anodes assembled in a discharged state. Therefore, there is a great need for anode substrates that can be manufactured cost-effectively for the efficient electrodeposition and delamination of metals, particularly metallic lithium and sodium. Disclosed anode materials, anodes, and anode manufacturing methods would make it possible to assemble electrochemical cells in dry indoor or even outdoor environments. The success of developing such anodes would be beneficial for commercial and industrial purposes. [Overview of the project]

[0006] Anode materials for electrochemical cells are disclosed. The anode material may include a matrix material:dispersion material composite. The anode material may include only a matrix material:dispersion material composite. The matrix material may include one or more alkali metals. The matrix material may include one or more alkaline earth metals. The matrix material may include one or more metallic alkali metals. The matrix material may include one or more metallic alkaline earth metals. The matrix material may include one or more substantially pure alkali metals. The matrix material may include one or more substantially pure alkaline earth metals. The matrix material may include alloys. The dispersion material may include metals. The dispersion material may include metallic metals. The dispersion material may include substantially pure metals. The dispersion material may include alloys of substantially pure metals. The metals in the dispersion material may be different from those in the matrix material. The matrix metal or multiple matrix metals and / or dispersion metal or multiple metals may be metals. The metals in the matrix material and / or the metals in the dispersion material may be substantially pure metals or alloys of substantially pure metals. The dispersion material may contain one or more transition metals. The dispersion material may contain one or more post-transition metals. The dispersion material may contain one or more metallic transition metals. The dispersion material may contain one or more metallic post-transition metals. The dispersion material may contain one or more substantially pure transition metals. The dispersion material may contain one or more substantially pure post-transition metals. The dispersion material may contain alloys of transition metals and / or substantially pure post-transition metals. The dispersion material may contain alloys of metallic transition metals and / or metallic post-transition metals. The dispersion material may contain substantially pure transition metals and / or substantially pure post-transition metals. The anode material may contain a single alkali metal and / or alkaline earth metal, and a single transition metal and / or post-transition metal. The anode material may include a single metallic alkali metal and / or a metallic alkaline earth metal, and a single metallic transition metal and / or a metallic post-transition metal.The anode material may include a single substantially pure alkali metal and / or substantially pure alkaline earth metal, and a single substantially pure transition metal and / or substantially pure post-transition metal. The alkali metal may include lithium, potassium, and / or sodium, and any mixtures or combinations thereof. One or more post-transition metals may include aluminum, gallium, indium, tin, and / or lead, and any mixtures or combinations thereof. The matrix material may have a lower melting point than the dispersion material. The matrix material may have a higher vapor pressure than the dispersion material. The matrix material may be lithium or sodium. The matrix material may be metallic lithium or sodium. The matrix material may be substantially pure lithium or sodium. The dispersion material may be aluminum. The dispersion material may be metallic aluminum. The dispersion material may be substantially pure aluminum.

[0007] An anode for an electrochemical cell is disclosed. The anode may comprise a disclosed anode material. The anode may further comprise a current collector and / or SEI layer. The current collector may comprise one or more conductive materials.

[0008] An electrochemical cell is disclosed. The electrochemical cell of the present invention may be a rechargeable electrochemical cell. The electrochemical cell may include a disclosed anode. The electrochemical cell may further include a cathode. The electrochemical cell may further include an electrolyte. At least a portion of the electrolyte may be located between the anode and the cathode. The electrolyte may be an organic electrolyte. The electrolyte may be an inorganic electrolyte. The electrolyte may be any mixture or combination of organic and / or inorganic electrolytes. The electrolyte may be in any state of matter. The electrolyte may be NH3, SO2, ether, Carbonate, or an electrolyte based on a nitrile solvent, or any mixture or combination thereof. The electrolyte may contain an electrolyte salt containing alkali metals and / or alkaline earth metals. The electrolyte may contain transition metals and / or post-transition metals containing an electrolyte salt. The matrix material may contain one or more metals in the electrolyte salt. The dispersion material may contain one or more metals in the electrolyte salt. The metal in the electrolyte salt may be Na. The metal in the electrolyte salt may be Al. The electrolyte may contain a salt containing alkali metals and / or alkaline earth metals and / or transition metals and / or post-transition metals. One or more metals in the anode material may be electrochemically active. One or more metals in the electrolyte salt may be matrix material and / or dispersion material. The matrix material and / or dispersion material may be electrochemically active. One or more metals in the electrolyte salt may be electrochemically active anode material. The alkali metal may be Na, and the post-transition metal in the electrolyte salt and / or anode material may be Al. The metals in the electrolyte salt may be Na and Al. The electrolyte salt may be NaAlCl4. The electrolyte may be NaAlCl4·XSO2, where x can be any positive real number. All or part of the anode can be used as a substrate for electrodepositing one or more matrix materials during charging. All or part of the anode can be used as a source of matrix material during discharge. The electrolyte may further contain one or more electrolyte additives. The electrolyte additives may include halogenated electrolyte additives. The halogenated electrolyte additives may include trifluoromethanesulfonyl chloride (CF3SO2Cl), thionyl chloride (SOCl2), SnCl4, and / or fluoroethylene carbonate (4-fluoro-1,3-dioxolan-2-one) or any mixture or combination thereof. Other electrolyte additives, including other halogenated electrolyte additives, are possible according to the present invention. The halogenated electrolyte additives may be any halogen-containing molecules. The halogen-containing molecules may be soluble in the electrolyte. The halogen-containing molecules may chemically react on the surface of the anode and / or cathode.The halogen-containing molecules may be involved in the formation of SEI on the surfaces of the anode and / or cathode. The cathode may comprise a cathode material capable of intercalation of cations. The cathode may comprise a cathode material capable of transformation reactions. The cathode may comprise a cathode liquid. The cathode may comprise any mixture or combination of the aforementioned cathode materials. Other cathodes are possible according to the present invention. A method for producing the disclosed anode material is described. The method comprises the steps of mixing a matrix material and a dispersion material, and heating the mixture to selectively melt the matrix material to produce a matrix material:dispersion material composite. The melting point of the matrix material may be lower than the melting point of the dispersion material. The heating temperature may be between the melting points of the matrix material and the dispersion material. The matrix material:dispersion material composite may be an intermediate matrix material:dispersion material composite. The intermediate matrix material:dispersion material composite may be chemically or mechanically treated to improve the properties of the matrix material:dispersion material composite. The improved properties may be a reduction in the size of the dispersion material and / or an increase in the uniformity of the matrix material:dispersion material composite.

[0009] The cathode material capable of conversion may include a transition metal:halogen compound. The transition metal in the transition metal:halogen compound may be Cu, and / or the halogen in the transition metal:halogen compound may be F. The transition metal in the transition metal:halogen compound may be CuF2.

[0010] The positive real number x of the electrolytic NaAlCl4·XSO2 can preferably be between 0.1 and 32, more preferably between 0.5 and 16, more preferably between 0.8 and 8, more preferably between 1.1 and 4, more preferably between 1.3 and 2, and more preferably between 1.4 and 1.6. According to the present invention, other electrolytes, electrolyte solvents, electrolyte salts, and electrolyte concentrations are possible. According to the present invention, the electrolyte can be any suitable electrolyte compatible with the anode and / or anode material of the present invention.

[0011] The separator according to the present invention may be any suitable separator. Examples of separator materials include, but are not limited to, glass, hydrocarbons, polymers, or ceramics, and also include glass fiber, paper, cellulose, polypropylene, polyethylene, acetylcellulose, PVDF, PTFE, PES, nylon, mixed cellulose ester (MCE), PETE, polyester, PEEK, and PAN.

[0012] A method for producing an anode from a disclosed anode material is disclosed. This method may include dispersing the prepared anode material onto a substrate. The anode material can be dispersed onto the substrate by any means known in the art.

[0013] This method can be used in the manufacture of equipment.

[0014] The use of the disclosed anode material, the disclosed anode, or the disclosed electrochemical cell is described. The disclosed anode material, the disclosed anode, or the disclosed electrochemical cell may be used in an apparatus. The apparatus may be an electrical apparatus. An electrical apparatus may include, for example, an electronic device, a battery or battery pack, a motor or actuator, an energy storage device, an energy or power supply device, an electric vehicle, a power tool, or any other device that can use the voltage and / or current generated by means of the anode material, anode, or electrochemical cell of the present invention.

[0015] The dispersed material may be in the form of particles. According to the present invention, particles mean minute or trace fragments of a substance, or small localized objects, whose physical or chemical properties, such as composition, shape, form, or size, are different from those of the matrix material.

[0016] According to the present invention, the metal may include alkali metals, alkaline earth metals, lanthanides, actinides, transition metals, post-transition metals, and alloys thereof. According to the present invention, the metal includes alloys of metals.

[0017] According to one embodiment of the present invention, the composite material may include sodium and aluminum (sodium:aluminum composite material). The matrix metal may be sodium. The dispersion material may be aluminum. The dispersion material may be in the form of particles. The aluminum particles may be dispersed in the sodium matrix material. The particles may be in the form of flakes.

[0018] This invention discloses a method for manufacturing anodes in a battery invention. These anodes can be used as a source of alkali metals and / or alkaline earth metals, such as lithium or sodium, in a battery cell assembled in a charged state, or as a deposition substrate for alkali metals and / or alkaline earth metals, such as lithium or sodium, in a battery cell assembled in a discharged state. [Brief explanation of the drawing]

[0019] [Figure 1] This is an anode material according to one embodiment of the present invention. [Figure 2] This is an electrochemical cell according to the present invention, wherein the anode comprises at least partially the anode material of the present invention. [Figure 3] This is an exemplary anode according to several embodiments of the present invention. [Figure 4] This is an exemplary means for producing anodes and self-supporting anode material films according to several embodiments of the present invention. [Figure 5] This is an exemplary means for producing an anode from a self-supporting anode material film, according to several embodiments of the present invention. [Figure 6] This is a photograph of an exemplary preferred anode material with a Na:Al mass ratio of 1:1. [Figure 7] This is a photograph of an electrode fabricated from an exemplary preferred anode material with a Na:Al mass ratio of 1:1. [Figure 8]Comparison of the change in Coulomb efficiency of a battery cell containing a CuCl2⇔CuCl + NaCl conversion cathode, a NaAlCl4·2SO2 electrolyte, and two versions of an anode, namely a Na:Al composite material having a mass ratio of Na:Al of 1:1 with respect to elemental sodium metal. The horizontal axis represents the number of cycles, and the unit on the vertical axis represents efficiency %. Graphs A and B show the scales when sufficient efficiency is achieved and the scale close to 100%, respectively. [Figure 9] Comparison of the change in discharge time / discharge capacity of a battery cell containing a CuCl2⇔CuCl + NaCl conversion cathode, a NaAlCl4·2SO2 electrolyte, and two versions of an anode, namely a Na:Al composite material having a mass ratio of Na:Al of 1:1 with respect to elemental sodium metal. The horizontal axis represents the number of cycles, and the unit on the vertical axis is s / μAh. [Figure 10] Comparison of the change in internal resistance of a battery cell containing a CuCl2⇔CuCl + NaCl conversion cathode, a NaAlCl4·2SO2 electrolyte, and two versions of an anode, namely a Na:Al composite material having a mass ratio of Na:Al of 1:1 with respect to elemental sodium metal. The horizontal axis represents the number of cycles, and the unit on the vertical axis is Ω. [Figure 11] Comparison of the change in average discharge voltage of a battery cell containing a CuCl2⇔CuCl + NaCl conversion cathode, a NaAlCl4·2SO2 electrolyte, and two versions of an anode, namely a Na:Al composite material having a mass ratio of Na:Al of 1:1 with respect to elemental sodium metal. The horizontal axis represents the number of cycles, and the unit on the vertical axis is V. [Figure 12] Comparison of the change in Coulomb efficiency of a battery cell containing a CuCl2⇔CuCl + NaCl conversion cathode, a NaAlCl4·2SO2 electrolyte, and two versions of the NaAlCl4·2SO2 electrolyte, namely without additive and using a 2 wt% CF3SO2Cl additive. The horizontal axis represents the number of cycles, and the unit on the vertical axis represents efficiency %. Graphs A and B show the scales when sufficient efficiency is achieved and the scale close to 100%, respectively. [Figure 13]Comparison of the change in discharge time / discharge capacity of a battery cell containing a CuCl2⇔CuCl+NaCl conversion cathode, a Na:Al composite material having a Na:Al mass ratio of 1:1, and two versions of a NaAlCl4·2SO2 electrolyte, namely, without additive versus using a 2 wt% CF3SO2Cl additive. The horizontal axis is the number of cycles and the unit of the vertical axis is s / μAh. [Figure 14] Comparison of the change in internal resistance of a battery cell containing a CuCl2⇔CuCl+NaCl conversion cathode, a Na:Al composite material having a Na:Al mass ratio of 1:1, and two versions of a NaAlCl4·2SO2 electrolyte, namely, without additive versus using a 2 wt% CF3SO2Cl additive. The horizontal axis is the number of cycles and the unit of the vertical axis is Ω. [Figure 15] Discharge capacity versus number of cycles of a rechargeable battery constructed with a Na:Al composite anode having a Na:Al mass ratio of 1:1, a CUF2 cathode, and a NaAlCl4·1.5SO2 electrolyte. The horizontal axis is the number of cycles and the unit of the vertical axis is mAh.

Mode for Carrying Out the Invention

[0020] Detailed embodiments of the present invention are disclosed herein with reference to the accompanying drawings.

[0021] The electrochemical cell according to the present invention may include an anode, a cathode, and an electrolyte at least a part of which is located between the anode and the cathode according to the present invention. The electrochemical cell may further include a separator between the anode and the cathode. The electrochemical cell may further include one or several charge carriers (current collectors). The anode and / or the cathode may also function as a current collector. The electrochemical cell may further include a housing. The electrochemical cell of the present invention may be a rechargeable electrochemical cell. The electrolyte may be in any state of matter. The electrolyte may be, for example, solid, liquid, glass or gel.

[0022] The anode of the electrochemical cell according to the present invention may include a composite material. The composite material may be in the form of a matrix material and a dispersion material. The matrix material may be continuous (i.e., continuously connected throughout the material). The dispersion material may be discontinuous (i.e., dispersed throughout the material or not continuously connected). The matrix material may be a single metal or an alloy of two or more metals. The dispersion material may be a single metal or an alloy of metals. The metal may be a metallic metal. The metal may be a substantially pure metal. The alloy may be an alloy of metallic or substantially pure metals. The dispersion material may be in the form of a spheroid, flakes, rods, polyhedra, or any other form or combination of forms (referred to herein as “particles (singular)” or “particles (plural)”. The dispersion material may be distributed or dispersed in the matrix material. The dispersion material may be substantially uniformly dispersed in the matrix material or may be unevenly distributed in the matrix material. The particle size may be substantially uniform or may have a particle size distribution. The particle size may preferably be between 0.1 and 1000 microns, more preferably between 0.1 and 100 microns, more preferably between 0.1 and 50 microns, and most preferably between 0.1 and 10 microns.

[0023] In this specification, metallic metal means a metal that is in an elemental or atomic state, or otherwise not bonded with one or more nonmetallic atoms within the molecule. Examples of metallic metals include metals in which electrons are in a three-dimensional delocalized state. In this specification, pure metal means a material containing a high concentration of metallic metal or an alloy of metallic metals. In this specification, high concentration means that the mass fraction of metallic metal is preferably greater than 90%, more preferably greater than 95%, more preferably greater than 98%, more preferably greater than 99%, more preferably greater than 99.5%, more preferably greater than 99.8%, and most preferably greater than 99.9%. According to the present invention, metals may include alkali metals, alkaline earth metals, transition metals and / or post-transition metals. Alkali metals include, but are not limited to, Li, Na, and K. According to the present invention, other alkali metals are possible. Alkaline earth metals include, but are not limited to, Be, Mg, Ca, and Sr. According to the present invention, other alkaline earth metals are possible. Transition metals include, but are not limited to, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, and Cd. Other transition metals are possible according to the present invention. The resulting metals include Al, Ga, In, or Sn. Other transition metals are possible according to the present invention.

[0024] According to one embodiment of the present invention, the composite material may comprise sodium and aluminum (sodium:aluminum composite material). The matrix metal may be sodium metal. The dispersed material may be aluminum metal. The dispersed material may be in form or particles. Aluminum particles may be dispersed in the sodium matrix material. The particles may be in the form of flakes. In this embodiment, the average size of the aluminum particles in flake form may be between 1 and 100 microns. The average flake size may be less than 20 microns. According to the present invention, other particle forms and sizes are possible.

[0025] A matrix material:dispersed material composite can be formed by any means known in the art. According to one method of the present invention, a matrix material:dispersed material composite is prepared by mixing a matrix material and a dispersed material and heating the mixture above the melting point of the matrix material but below the melting point of the dispersed material to form a composite material of continuous matrix material and dispersed distributed material particles. One or both of the matrix material and the dispersed material may be in the form of a powder (i.e., an aggregate of particles). The composite material may then be further processed, for example, by chemical or physical means, for example, in a mortar mixer, for example, with mortar.

[0026] Figure 1 illustrates an anode material (1) according to one embodiment of the present invention. The anode material (1) may include a matrix material (2):dispersion material (3) composite material. As shown in the cross-sectional view of Figure 2, the anode material (1) may include all or part of the anode (4) of an electrochemical cell stack (5) according to the present invention. The electrochemical cell stack (5) may further include a cathode (6). The electrochemical cell stack (5) may further include a separator or spacer (7) between the anode (1) and the cathode (6). The anode (4) and / or cathode (6) may further include one or more solid electrolyte interface (SEI) layers (8) on the anode (4) and / or cathode (6). The cell stack (5) may further include at least partially an electrolyte (not shown) between the anode (4) and the cathode (6).

[0027] The cathode (6) may include, but is not limited to, any suitable cathode material, including a cathode material capable of cation intercalation, a cathode material capable of transformation reactions, and / or a cathode liquid. Other cathode materials are possible according to the present invention. In this specification, a cathode material capable of cation intercalation means a material in which the concentrations of implanted and detached cations and electrons change without changing the molecular crystal structure of the host material. In this specification, a cathode material capable of transformation reactions means a material in which the concentrations of implanted and detached cations and electrons change in accordance with a change in the molecular crystal structure of the host material. In this specification, a cathode liquid means a reversibly transformable cathode material in a liquid state.

[0028] A suitable cathode according to the present invention may include a transition metal:halogen compound. The transition metal:halogen compound may be the active material of the cathode. The transition metal:halogen compound may be, for example, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, O, Ir, Pt, Au, Hg, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg and / or Cn and / or any combination thereof. The transition metal:halogen compound may be, for example, F, Cl, Br and / or I and / or any combination thereof. The transition metal may include Cu, and the halogen may include F. The transition metal:halogen compound may include Cu and F as the transition metal and halogen, respectively. Cu and F halogen compounds containing transition metals may include CuF2 active material. The cathode and / or cathode material may further include conductive additives. Conductive additives may include conductive materials. Conductive materials may be metals or metallic materials. Metals and / or conductive materials may contain carbon. Carbon-containing additives may be carbon additives. Metal conductive additives may be nanomaterials. Conductive additives may be in the form of tubes, wires, balls or flakes. Conductive additives may contain carbon or its allotropes and / or metals. Conductive additives may be in the form of conductive high aspect ratio particles. Metals and / or carbon containing conductive additives may be nanotubes (e.g., carbon nanotubes), nanowires (e.g., metallic nanowires), nanoballs (e.g., fullerenes), nanoflakes (e.g., graphene or graphite), or hybrids or combinations thereof (e.g., carbon nanobuds), Ketjenblack, hard carbon, nanofibers, activated carbon, reduced graphene oxide, and any combination thereof.

[0029] The mass ratio of (transition metal:halogen compound):(conductive additive) in the cathode and / or cathode material, for example, CuF2:conductive carbon additive, is 20:1 to 1:10, more preferably 15:1 to 1:4, more preferably 10:1 to 1:2, more preferably 7:1 to 1:1, more preferably 5:1 to 3:1 or any combination thereof, most preferably about 4:1.

[0030] According to the present invention, other cathodes, cathode materials, active materials, conductive additives, carbon, and mass ratios are possible.

[0031] Figure 3 illustrates various exemplary embodiments of the anode (4) according to the present invention in cross-section. As shown in Embodiment 3A, the anode (4) may be made of only an anode material (1) comprising a matrix material (2) and a dispersion material (3). In this case, the anode material may also function as an anode current collector (9). As shown in Embodiments 3B to 3E, the anode material (1) may be deposited on and / or inside a separate anode current collector (9). The current collector (9) may include, for example, any suitable conductive material compatible with the anode material (1) and / or an electrolyte (not shown) under the charging and / or discharging and / or storage voltage and / or current of an electrochemical cell (5). The current collector (9) may be in the form of a foil or film of the current collector material, for example, as shown in Figures 3B and 3C. The anode material (1) may be on one side of the current collector (9), as shown in Figure 3B, or on both sides of the current collector (9), as shown in Figure 3C. The anode current collector (9) may be in the form of an open structure of the anode current collector material, such as a mesh, perforated foil, weave, or other forms including gaps or spaces, as shown, for example, in Figure 3D and Figure 3E. In such cases, the anode material (1) may be positioned to completely or partially fill the gaps in the open structure of the anode current collector (9). The anode material (1) may be on one side of the current collector (9), as shown in Figure 3D, or on both sides of the current collector (9), as shown in Figure 3E.

[0032] The anode materials disclosed herein may be used as current collector substrates for electrodeposition of metallic metals in electrochemical cells assembled in a discharged state, or as charged metallic metal electrodes in electrochemical cells assembled in a charged state.

[0033] The material of the separate anode current collector (9) can be any suitable conductive material. In this specification, a conductive material is defined as having a conductivity of about 1 × 10 at 20°C. 5 This refers to materials with an electrical conductivity greater than σ(S / m). Examples of conductive materials include metallic materials. Metallic materials include materials in which electrons are in a three-dimensional delocalized state. Examples of metallic materials may include metals. Examples of metals may include Hg, Dy, Eu, Ce, Er, Ho, La, Pr, Tm, Nd, Y, Sc, Lu, Po, Am, Ti, Zr, Sb, Fr, Ba, Hf, As, Yb, U, Pb, Cs, V, Pa, Re, Tl, Th, Tc, Ga, Nb, Ta, Sr, Cr, Rb, Sn, Pd, Pt, Fe, Li, Os, In, Ru, Cd, K, Ni, Zn, Co, Mo, W, Ir, Na, Rh, Mg, Ca, Be, Al, Au, Cu, Ag, and mixtures, alloys, or combinations thereof. Metallic materials may include allotropes of carbon. Allotropes of carbon include diamond, graphite, graphene, amorphous carbon, fullerene, carbon nanotubes, carbon nanobuds and glassy carbon, carbon nanoforms, lonsdaleite, calvin, or other allotropes of carbon and / or any combination thereof. Other metallic materials are also possible according to the present invention. The selection of a suitable current collector material depends, for example, on details of the battery composition, chemical and electrochemical stability with respect to the electrolyte, charging voltage and / or charging and / or discharging current.

[0034] A matrix material:dispersed material composite anode material can be prepared by any means known in the art. One method of preparation is to create a matrix material:dispersed material composite by heating a mixture of matrix material and dispersed material particles above the melting point of the matrix material but below the melting point of the dispersed material. The composite material can then be processed to improve material properties such as particle size and uniformity of the composite material. This can be done by any means known in the art, for example, by mortarizing in a mortar mixer. According to the present invention, any heating and / or processing time is possible. Preferably, the processing time is between 1 minute and 1000 minutes, more preferably between 2 minutes and 100 minutes, and most preferably between 5 minutes and 50 minutes. The heating and / or mortaring can be carried out under any suitable atmosphere. Preferably, the atmosphere is inert to one or both of the matrix material and the dispersed material. Examples include, but are not limited to, argon and nitrogen atmospheres. The mass ratio of the matrix material:dispersed material mixture can be any defined ratio. The ratio is preferably between 100:1 and 1:100, more preferably between 50:1 and 1:50, more preferably between 20:1 and 1:20, more preferably between 10:1 and 1:10, more preferably between 5:1 and 1:5, more preferably between 3:1 and 1:3, more preferably between 2:1 and 1:2, and most preferably between 1.1:1 and 1:1.1.

[0035] The anode material (1) can be processed by any means known in the art to create an anode (4). Examples include rolling by nip, dip coating, calendering, and hydraulic press. An exemplary means of forming an anode (1) according to the present invention is shown in Figure 4. As shown in Figure 4A, the anode material (1) can be drawn out through a nip (10) to form one of the anodes (4), where the anode (4) is also a current collector (9) or a self-supporting anode material film (12). As shown in Figure 4B, the anode material (1) can be drawn out through a nip (10) to form an anode (4) together with a current collector (9), comprising a separate anode material (1) and a current collector substrate (9). As shown in Figure 4C, the anode material (1) can be drawn through the nip (10) and, together with the current collector (9), form an anode (4) containing separate anode material (1) in two layers on either side of the current collector substrate (9). Figure 5 shows a method of forming a single-sided (Figure 5A) or double-sided (Figure 5B) anode (4) by combining a self-supporting anode material film (12), manufactured in Figure 4 or by other methods, with a current collector (9) substrate, by passing one or two self-supporting anode material films (12) through a laminated nip (11).

[0036] Surprisingly, it has been discovered that the electrochemical performance of the matrix-dispersed material composite anode can be further improved by using halogenated electrolyte additives. Herein, a halogenated electrolyte additive is defined as a halogen-containing molecule that is soluble in the electrolyte and chemically reacts at the anode or cathode surface. According to the present invention, any halogenated electrolyte additive can be used. Herein, halogenated means that the molecule contains a halogen. Halogens include, but are not limited to, Fl, Cl, Br, and I. [Examples]

[0037] In one embodiment of this method, the sodium:aluminum composite anode material is prepared by first mixing sodium metal and aluminum flake powders and heating the sodium and aluminum flake mixture at a temperature above the melting point of sodium (98°C) but below the melting point of aluminum (660°C). In this example, the temperature was approximately 120°C. The sodium:aluminum mass ratio of the mixture in this embodiment was approximately 1:1. In this embodiment of the present invention, the ratio is preferably between 5:1 and 1:5, more preferably 3:1 and 1:3, more preferably 2:1 and 1:2, and most preferably between 1.1:1 and 1:1.1. Next, the obtained Na:Al intermediate composite material was mortarized in a mortar mixer for 10 minutes while cooling to create the final composite material. This heating and mortarizing was carried out under an argon atmosphere, which is inert to metallic sodium.

[0038] Surprisingly, it was discovered that when sodium cooled below its melting point, mortar action produced a homogeneous composite material with a flaky appearance from the sodium:aluminum mixture. The appearance of the obtained material is shown in Figure 6. The formation of this homogeneous composite material is surprising because sodium is known to have poor wetting properties with other materials, i.e., sodium generally has a low affinity for dispersion. Surprisingly, when the obtained sodium:aluminum composite material was transferred to the ambient air, its atmospheric stability was significantly higher than that of ordinary sodium metal, and the composite material retained its lustrous metallic appearance. In a dry indoor environment, the sodium:aluminum composite material proved to be stable enough to enable the manufacture of battery electrodes. The sodium:aluminum composite material proved to be soft enough to be compressed and rolled into a continuous film and / or laminated into a current collector film or current collector mesh. When the composite material was heated to a temperature higher than room temperature but lower than the melting point of sodium, its softness was found to increase further. This mechanical property enables the simple and cost-effective manufacture of electrodes from the sodium:aluminum composite material disclosed herein. Figure 7 shows the anode electrode created by pressing a sodium:aluminum composite material into an aluminum mesh current collector.

[0039] The anode materials disclosed herein can be used as current collector substrates for metallic sodium electrodeposition in battery cells assembled in a discharged state, or as charged sodium electrodes in battery cells assembled in a charged state.

[0040] The electrochemical properties of the obtained anodes were evaluated using a battery cell containing the NaAlCl4·2SO2 electrolyte formulation. This electrolyte was selected for evaluation because it supports the reversible cycle of metallic sodium anodes, and therefore allows for electrochemical comparison with anodes of metallic sodium alone. The cathode used was a discharged cathode containing the Cu + 2NaCl active material formulation. After charging the cathode to the CuCl2 state, the cathode was cycled according to the CuCl2 ⇔ CuCl + NaCl conversion reaction. The electrochemical performance of the Na:Al composite anode at a 1:1 mass ratio compared to a metallic sodium anode was evaluated by measuring the following three parameters during the battery cycle: i) Coulomb efficiency, ii) discharge time / discharge capacity ratio, and iii) internal resistance of the cell. The measurement data are shown in Figures 8 to 10. As can be seen from Figure 8, the average Coulomb efficiency is similar in both cases. However, the variation in Coulomb efficiency is smaller for the Na:Al composite anode, indicating that the electrode-electrolyte interface is more stable. The discharge program consists of a series of decreasing discharge currents, with each stage ending at a critical voltage of 3.2V. Since a longer discharge time indicates a transition towards lower currents, the discharge time in such a discharge program is related to the resistance of the electrode-electrolyte interface. The discharge time is divided by the cathode discharge capacitance to eliminate the effect of changes in cathode capacitance. As can be seen from Figure 9, the discharge time of the Na:Al composite anode is significantly shorter, indicating a significantly lower resistance at the electrode-electrolyte interface. The internal resistance of the cell is estimated from the changes in voltage data at the charging start and stop events. As can be seen from Figure 10, the internal resistance is significantly lower for the Na:Al composite anode, again indicating a significantly lower resistance at the electrode-electrolyte interface. As can be seen from Figure 11, the average discharge voltage is almost the same for both the Na:Al composite anode and the metallic Na anode. Therefore, the performance improvements described herein are not disadvantageous with respect to the cell voltage. In short, these data demonstrate the improved performance of the Na:Al composite anode cell disclosed herein compared to cells containing a single metallic Na anode.

[0041] As an anode for a cell assembled in a charged state, a preferred embodiment with a 1:1 mass ratio between Na:Al composite materials is a high-density anode with a gravimetric capacity of 550 mAh / g and can operate at a potential of -2.7 V relative to a standard hydrogen electrode. As an anode substrate for a cell assembled in a discharged state, a preferred embodiment with a 1:1 mass ratio between Na:Al composite anodes supports a highly efficient and durable anode cycle of metallic sodium deposition and exfoliation. In both cases, the electrochemical performance is superior to that of an anode consisting of pure metallic sodium. Battery cells using the anodes disclosed herein can be assembled in a dry indoor environment.

[0042] Surprisingly, it was discovered that the electrochemical performance of the Na:Al composite anode disclosed herein can be further improved by using a halogenated electrolyte additive. The anode performance of the Na:Al composite material was compared with two versions of the NaAlCl4·2SO2 electrolyte, namely, without additives and with 2 wt% CF3SO2Cl additive. Anode performance was evaluated by measuring the following three parameters during battery cycling: i) Coulomb efficiency, ii) discharge time / discharge capacity ratio, and iii) internal resistance of the cell. The measurement data are shown in Figures 12 to 14. As can be seen from Figure 12, the Coulomb efficiency of the cell with the CF3SO2Cl additive-containing electrolyte initially exceeds 100%, indicating the consumption of the electrolyte additive. However, after about 50 cycles, the Coulomb efficiency of the cell with the CF3SO2Cl additive-containing electrolyte converges very close to 100%, showing better Coulomb efficiency than the electrolyte without additives. As can be seen from Figures 13 and 14, cells with electrolytes containing CF3SO2Cl additives exhibit slightly shorter discharge times, slightly lower internal resistance, and slightly lower resistance at the electrode-electrolyte interface. Furthermore, Figures 13 and 14 show that the electrolytes containing CF3SO2Cl additives exhibit smaller resistance fluctuations and a more stable electrode-electrolyte interface. In short, these data demonstrate that the anodic performance of the Na:Al composite anodes disclosed herein can be further enhanced by using one or more halogenated electrolyte additives. Long-term cycle stability is also demonstrated by these data.

[0043] An exemplary rechargeable cell was manufactured according to one embodiment of the present invention using the following cell structure. The anode electrode consisted of a Na:Al composite material with a mass ratio of Na to Al metal of 1:1. The cathode electrode contained a CuF2 active material with a mass ratio of CuF2 to a conductive carbon additive of 4:1, although according to the present invention, other cathodes, cathode materials, active materials, conductive additives, carbon, and mass ratios are possible. The electrodes were 2.5 cm². 2It had the following surface area. The electrolyte had a NaAlCl4·1.5SO2 composition, and although we used a glass fiber separator, other electrolytes, electrolyte compositions, and separator materials are possible according to the present invention. Figure 15 shows the relationship between the number of cycles and the discharge capacity of the cell in the above example. From 1 to 70 cycles, it is shown that the discharge capacity increases as larger CuF2 particles in the cathode are gradually activated. The cell was left idle for 5 days at the 70th cycle. Starting from about 70 cycles, the cell showed a stable discharge capacity. The average cell voltage during discharge was 3.35V. This cell demonstrates the stable operation of the anode structure disclosed herein in a rechargeable cell.

[0044] The examples described above illustrate the principles of the present invention in one or more specific uses, but it will be apparent to those skilled in the art that numerous modifications of embodiments, uses, and details can be made without exercising inventive ability and without departing from the principles and concepts of the present invention. Therefore, the present invention is not intended to be limited except by the claims set forth below.

Claims

1. Anode material (1) for a rechargeable electrochemical cell containing an electrolyte which is a liquid, glass, or gel, wherein the anode material (1) comprises a matrix material:dispersion material composite, the matrix material (2) comprises a sodium metal, the dispersion material (3) comprises a metal, and the metal which is the dispersion material is different from that of the matrix material (2).

2. The anode material (1) according to claim 1, wherein the dispersed material (3) comprises one or more transition metals and / or post-transition metals, and one or more of the post-transition metals comprises aluminum, gallium, indium, tin and / or lead.

3. The anode material (1) according to claim 1 or 2, wherein the dispersed material (3) contains aluminum.

4. an anode (4) for an electrochemical cell (5), comprising an anode material (1) according to any one of claims 1 to 3.

5. The anode (4) according to claim 4, wherein the anode (4) further comprises a current collector (9) and / or an SEI layer.

6. An electrochemical cell (5) comprising a cathode (6), an anode (4) according to claim 4 or 5, and an electrolyte in which at least a portion thereof is located between the anode (4) and the cathode (6).

7. The aforementioned electrolyte is NH ３ SO ２ The electrochemical cell (5) according to claim 6, which is an electrolyte based on an ether, carbonate, or nitrile solvent, or any mixture or combination thereof.

8. The electrochemical cell (5) according to claim 6 or 7, wherein the electrolyte comprises an electrolyte salt containing an alkali metal and / or alkaline earth metal and / or transition metal and / or post-transition metal.

9. The electrochemical cell (5) according to claim 8, wherein the matrix material (2) and / or the dispersion material (3) contains one or more metals in the electrolyte salt.

10. The electrochemical cell (5) according to claim 8 or 9, wherein the metals in the electrolyte salt are Na and Al.

11. The aforementioned electrolyte salt is NaAlCl ４ The electrochemical cell (5) according to claim 10.

12. The electrolyte is NaAlCl ４ ・xSO ２ The electrochemical cell (5) according to any one of claims 6 to 11, wherein (x is a positive real number).

13. The electrochemical cell (5) according to any one of claims 6 to 12, wherein all or part of the anode (4) is used as a substrate for electrodeposition of one or more matrix materials during charging, and / or, all or part of the anode (4) is used as a source of matrix material (2) during discharge.

14. The electrochemical cell (5) according to any one of claims 6 to 13, wherein the electrolyte further comprises one or more electrolyte additives.

15. The electrochemical cell (5) according to claim 14, wherein the electrolyte additive includes a halogenated electrolyte additive.

16. The halogenated electrolyte additive is trifluoromethanesulfonyl chloride (CF ３ SO ２ Cl), thionyl chloride (SOCl ２ ), SnCl ４ , and / or fluoroethylene carbonate (4-fluoro-1,3-dioxolan-2-one) or any mixture or combination thereof, the electrochemical cell (5) according to claim 15.

17. The electrochemical cell (5) according to any one of claims 6 to 16, wherein the cathode (6) comprises a cathode material capable of intercalation of cations, a cathode material capable of conversion reactions, a cathode solution, or any mixture or combination thereof.

18. The electrochemical cell (5) according to claim 17, wherein the cathode material capable of conversion includes a transition metal:halogen compound.

19. The transition metal in the transition metal:halogen compound is Cu, and / or the halogen in the transition metal:halogen compound is F, and / or the transition metal:halogen compound is CuF ２ The electrochemical cell (5) according to claim 18.

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