Battery materials and methods for preparing them, and batteries

Abstract

To provide a battery material having high coulombic efficiency and excellent electrochemical performance.SOLUTION: A battery material, a preparation method thereof, and a battery are provided. The material includes: an active material configured to undergo a chemical reaction during battery charging and / or discharging; and one or more metal atoms configured to retain one or more oxygen atoms of the active material and to passivate the one or more oxygen atoms of the active material during the battery charging and / or discharging.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This invention relates to battery materials, methods for preparing them, and batteries. [Background technology]

[0002] Conventional structures and shapes of electrodes in certain rechargeable batteries involve coating aluminum foil with an active material to form the positive electrode and copper foil with an active material to form the negative electrode. To increase the energy density of the battery, the use of high-capacity negative electrode materials (e.g., silicon) is required. During the lithium-ion process, lithium and silicon form a lithium-silicon alloy, causing volume expansion of up to 400%, leading to rupture and degradation of the electrode structure. These are among the main obstacles to improving the energy density of certain rechargeable batteries (e.g., lithium-ion batteries).

[0003] Lithium-ion batteries (LIBs) are used in many portable electronic devices, power tools, electric vehicles, and internal combustion engine vehicles. Typically, an LIB consists of a lithium-containing positive electrode material and a lithium-receiving negative electrode material. During charging, lithium moves from the positive electrode to the negative electrode. During discharging, some of the lithium returns to the positive electrode. The Coulomb efficiency is defined as the ratio of lithium ions released per cycle during the discharge period to the lithium ions moved to the negative electrode during the charging period.

[0004] Until now, lithium-ion batteries (LIBs) have been the primary choice for renewable energy battery applications and require large-scale energy storage systems. However, many of the materials used in conventional LIBs have low storage capacity, meaning they can only store small amounts of energy per charge, resulting in insufficient battery performance.

[0005] CN105399100A discloses a method for preparing nanoporous silicon by alloying silicon powder and magnesium powder to prepare a precursor Mg2Si / Mg composite material, and then dealloying the resulting product by pickling. However, water molecules inevitably react with elemental silicon during the pickling process, irreversibly oxidizing the elemental silicon. This silicon oxide generates irreversible products with lithium ions during the charging period, negatively impacting the Coulomb efficiency.

[0006] CN114597375A proposes a method to improve the Coulomb efficiency of silicon oxide by reducing silicon oxide with highly inert elemental metals (e.g., silver, copper, nickel, iron, and cobalt) to lower the degree of oxidation of elemental silicon and improve the Coulomb efficiency of elemental silicon, which is the anode material. However, these inert metals (e.g., silver) are expensive, which is disadvantageous for the mass production and commercialization of elemental silicon as an anode material.

[0007] CN115053364A discloses a method for improving Coulomb efficiency by adding zirconium metal to pure silicon, but this method only improves Coulomb efficiency by 2%, which is ineffective.

[0008] The methods disclosed in the three aforementioned patent publications, which use various inert metal elements to reduce porous silicon or nanosilicon, have practical problems and make it difficult to substantially improve the Coulomb efficiency of silicon. [Overview of the Initiative]

[0009] In view of the problems of the prior art, one object of the present invention is to provide a battery material having high Coulomb efficiency and excellent electrochemical performance. Another object of the present invention is to provide a battery containing the material. Yet another object of the present invention is to provide a method for preparing the material.

[0010] According to one aspect of the present invention, the present invention is Active materials arranged to cause chemical reactions during the charging and / or discharging periods of a battery, One or more metal atoms arranged to retain one or more oxygen atoms of the active material and to deactivate one or more oxygen atoms of the active material during the charging and / or discharging period of the battery, The present invention provides battery materials, including [the specified element].

[0011] According to the material of the present invention, preferably, the metal atoms form a complex with the active material.

[0012] According to the material of the present invention, preferably, the metal atoms bond to oxygen atoms on the surface of the active material within the complex.

[0013] According to the material of the present invention, preferably, the metal atoms are bonded to oxygen atoms on the surface of the active material by covalent bonds.

[0014] According to the material of the present invention, preferably, the metal atoms remain bonded to the oxygen atoms during the charging and / or discharging periods of the battery.

[0015] According to the material of the present invention, preferably, the metal atoms react with the oxygen atoms to form an oxide within the complex.

[0016] According to the material of the present invention, preferably, the oxide forms at least one of amorphous and polycrystalline materials.

[0017] In the material according to the present invention, preferably, the metal atoms retain the oxygen atoms and deactivate the oxygen atoms, thereby improving the Coulomb efficiency of the material.

[0018] According to the material of the present invention, preferably, the metal atom is one or more selected from Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, Ti, La, Ce, and Hf.

[0019] According to the material of the present invention, preferably, the metal atom holds the oxygen atom and is embedded in the active material so as to inactivate the oxygen atom.

[0020] According to the material of the present invention, preferably, the metal atom is embedded in the active material as at least one of a metal simple substance, a metal oxide, a metal hydroxide, a metal acetate, a metal nitrate, a metal sulfate, and a metal carbonate.

[0021] According to the material of the present invention, preferably, the active material is one or more selected from a semimetal element, an oxide of a semimetal element, a metal element, and an oxide of a metal element.

[0022] According to the material of the present invention, preferably, the semimetal element is Si and / or B.

[0023] According to the material of the present invention, preferably, the active material is Si and contains at least one of SiO

[0028] , , , , ,

[0027] , ,

[0026] (where 0 < x < 2) and SiO2.

[0024] According to the material of the present invention, preferably, the active material is in a particulate form, and the particle diameter of the active material is 5 nm to 5 mm.

[0025] According to the material of the present invention, preferably, the active material is used as a negative electrode material in the battery.

[0026] According to another aspect of the present invention, the present invention provides a battery including a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode is made of the above material, and the electrolyte is ionically connected between the negative electrode and the positive electrode.

[0027] According to the battery of the present invention, preferably, during the charging period of the battery, the metal ions of the positive electrode move to the negative electrode, and during the discharging period of the battery, the metal ions return to the positive electrode.

[0028] According to the battery of the present invention, preferably, the metal ions are not trapped by oxygen atoms in the negative electrode during the discharge period of the battery.

[0029] According to the battery of the present invention, preferably, the metal ions are one or more selected from Li, Na, K, Ca, and Mg.

[0030] According to another aspect of the present invention, the present invention is A step of preloading one or more types of metal atoms into an active material, wherein the active material is arranged to undergo a chemical reaction during the charging and / or discharging periods of the battery, and the metal atoms are arranged to retain one or more oxygen atoms on the surface of the active material and to deactivate one or more oxygen atoms on the surface of the active material during the charging and / or discharging periods of the battery. A method for preparing the battery material, including the above.

[0031] According to the method of the present invention, preferably, one or more types of metal atoms are preloaded onto the active material by annealing the active material and the material containing the metal atoms in an atmosphere selected from helium gas, nitrogen gas, and argon gas at an annealing temperature of 500°C to 1200°C.

[0032] According to the method of the present invention, preferably, increasing the annealing temperature improves the Coulomb efficiency of the battery.

[0033] According to the method of the present invention, preferably, the metal atoms are preloaded onto the active material by processing the active material and the material containing the metal atoms in a high-energy ball mill, mixing the active material and the material containing the metal atoms, and then heat-treating them in at least one atmosphere selected from helium gas, nitrogen gas, and argon gas. [Brief explanation of the drawing]

[0034] [Figure 1] This is an SEM image of the porous silicon particles obtained in Example 1. [Figure 2] This is a pore size distribution diagram of the porous silicon particles obtained in Example 1. [Figure 3] This is an X-ray diffraction pattern of the battery material obtained in Example 1. [Figure 4] This is an X-ray diffraction pattern of the battery material obtained in Example 2. [Figure 5] This is an X-ray diffraction pattern of the battery material obtained in Example 3. [Modes for carrying out the invention]

[0035] The inventors have found through research, testing, and experimentation that metalloids and metalloid oxides such as silicon-based materials have the potential to become high-capacity negative electrodes for lithium-ion batteries. However, metalloids with a high surface area (e.g., Si) are highly reactive, and after entering the crystal lattice during charging, they become metalloids (e.g., Li x Si reacts with the electrolyte and traps lithium within the material, reducing the overall reversibility of lithium insertion and desorption.

[0036] During the charging process, lithium ions (Li + Lithium ions are stored by reacting with Si, and lithium ions are released during the discharge process. Ideally, the Coulomb efficiency of the negative electrode should be close to 100%, meaning that the amount of lithium ions reaching the negative electrode should be equal to the amount of lithium ions removed. If lithium ions are trapped at the negative electrode, the Coulomb efficiency will be less than 100%. The usable capacity and energy density of the battery will be lower because they depend on the amount of reversible lithium ions.

[0037] The inventors have found that oxygen on the surface of the negative electrode material adversely affects the charge-discharge process. In particular, some oxygen deactivates Si, thereby reducing the total amount of Li that can be inserted and decreasing the storage capacity. During the lithiation process (i.e., the charging process), some oxygen reacts with lithium and forms irreversible products during the lithiation process, of which Li is trapped, reducing the reversibility of Li ions, i.e., the initial Coulomb efficiency of the material. Some oxygen gradually dissolves into the electrolyte, adversely affecting the Coulomb efficiency of the material. Therefore, lithium is mainly trapped by oxygen in the crystal lattice, offsetting the advantage of the higher capacity of the active material.

[0038] <Battery materials> Based on the above findings, the present invention provides an active material arranged to undergo a chemical reaction during the battery charging and / or discharging period, and a battery material comprising one or more metal atoms arranged to retain one or more oxygen atoms on the surface of the active material and to deactivate one or more oxygen atoms on the surface of the active material during the battery charging and / or discharging period. The battery according to the present invention is preferably a lithium-ion battery. This prevents lithium from being trapped in oxygen within the crystal lattice and improves the Coulomb efficiency of the material. The active material according to the present invention is used as a negative electrode material for a battery.

[0039] In the material according to the present invention, the metal atom can form a complex with the active material. This is advantageous for improving the stability of the material. The active material has oxygen atoms on its surface. In the complex, the metal atom is bonded to the oxygen atoms on the surface of the active material. In some embodiments, the metal atom can be bonded to the oxygen atoms on the surface of the active material by covalent bonds. In some embodiments, the metal atom can be bonded to the oxygen atoms on the surface of the active material by coordination bonds.

[0040] According to a preferred configuration of the present invention, the metal atoms remain bonded to the oxygen atoms during the charging and / or discharging periods of the battery. This effectively prevents and reduces the trapping of lithium in oxygen within the crystal lattice. The reaction between the metal atoms and the oxygen atoms can form an oxide within the complex. The oxide according to the present invention is formed as an amorphous and / or polycrystalline material. The Coulomb efficiency of the material is improved by the metal atoms holding and deactivating the oxygen atoms. Specifically, the metal atoms are embedded in the active material to hold and deactivate the oxygen atoms.

[0041] In some embodiments, the active material has an oxide on its surface composed of the active material and oxygen atoms, and at least a portion of the oxygen atoms in the oxide are bonded to a metal element. Specifically, at least 50% of the oxygen atoms on the surface of the active material are bonded to the metal element, preferably at least 80% of the oxygen atoms on the surface of the active material are bonded to the metal element, and more preferably at least 90% of the oxygen atoms on the surface of the active material are bonded to the metal element. In some embodiments, all of the oxygen atoms on the surface of the active material are bonded to the metal element.

[0042] The mass ratio of the active material to the metal atoms may be 10:(0.2~5), preferably 10:(0.5~3), and more preferably 10:(0.8~2). In some embodiments, the mass ratio of the active material to the metal atoms is 10:(1~1.2). The mass of the metal atoms is calculated using the mass of its oxide.

[0043] metal atom The metal atom according to the present invention is one or more selected from alkali metal elements, alkaline earth metal elements, group IIIA elements, group IIIB elements, and group IVB elements. Examples of alkali metal elements include, but are not limited to, Na, K, Rb, and Cs. Preferably, the alkali metal element is K. Examples of alkaline earth metal elements include, but are not limited to, Ca, Mg, and Sr. Preferably, the alkaline earth metal element is Ca. Examples of group IIIA elements include, but are not limited to, Al and Ga. Preferably, the group IIIA element is Al. Examples of group IIIB elements include, but are not limited to, Sc, Y, and lanthanides. Examples of lanthanides include, but are not limited to, La and Ce. Preferably, the group IIIB element is Y. Examples of group IVB elements include, but are not limited to, Ti and Zr. Preferably, the group IVB element is Zr.

[0044] According to one embodiment of the present invention, the metal atoms are a combination of alkaline earth metal elements, alkali metal elements, and group IVB elements. The mass ratio of the alkaline earth metal elements, alkali metal elements, and group IVB elements may be (0.1~1):(0.1~1):1, preferably (0.2~0.8):(0.2~0.8):1, and more preferably (0.3~0.6):(0.3~0.6):1. The mass of each of the above elements is calculated by converting it to the mass of its oxide.

[0045] According to another embodiment of the present invention, the metal atom is a Group IIIB element.

[0046] According to another embodiment of the present invention, the metallic elements are a combination of Group IIIA elements and alkali metal elements. The mass ratio of Group IIIA elements to alkali metal elements may be (0.5 to 2):1, preferably (0.8 to 1.5):1, and more preferably (1 to 1.2):1. The mass of each of the above elements is calculated based on the mass of their oxides.

[0047] In the material according to the present invention, the metal atom is one or more selected from Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, Ti, La, Ce, and Hf. In some embodiments, the metal atom is one or more selected from Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, and Ti. In a preferred embodiment, the metal atom is one or more selected from K, Ca, Zr, Al, and Y. According to one embodiment of the present invention, the metal atom is a combination of K, Ca, and Zr. According to another embodiment of the present invention, the metal atom is Y. According to another embodiment of the present invention, the metal atom is a combination of K and Al.

[0048] In the material according to the present invention, the metal atom can be supplied from the simple substance of the metal or its compound. The compound of the metal atom may be one or more selected from metal oxides, metal hydroxides, metal acetates, metal nitrates, metal sulfates, and metal carbonates. All such substances can adopt commercially available ones. In some embodiments, the metal atom is embedded in the active material as at least one of a metal simple substance, a metal oxide, a metal hydroxide, a metal acetate, a metal nitrate, a metal sulfate, and a metal carbonate. Preferably, it is embedded in the active material as the metal oxide.

[0049] active material In the material according to the present invention, the active material is preferably a semimetal (Me)-based material. The active material may be one or more selected from a semimetal element, an oxide of the semimetal element, a metal element, and an oxide of the metal element. The semimetal element is preferably Si and / or B. Specific examples of the semimetal (Me)-based material include, but are not limited to, a silicon-based material and a boron-based material. In some embodiments, the active material is silicon and contains at least one of SiO x (where 0 < x < 2) and SiO2. According to one embodiment of the present invention, the active material is SiO xIt is a silicon-based material including (here, 0 < x < 2). According to another embodiment of the present invention, the active material is a silicon-based material containing SiO2. According to another embodiment of the present invention, the active material is SiO x It is a silicon-based material including (here, 0 < x < 2) and SiO2.

[0050] The active material according to the present invention is a silicon-based material, and it preferably has at least one of SiO x (here, 0 < x < 2) and SiO2 on the surface of the active material. According to one embodiment of the present invention, the active material is a silicon material having a pore structure inside and / or on the surface (hereinafter, also referred to as "porous silicon material").

[0051] In the material according to the present invention, the active material may be in particle form, and the particle diameter of the active material is 5 nm to 5 mm, preferably 500 nm to 50 μm, more preferably 1 to 30 μm, and most preferably 1 to 5 μm. The particle diameter can be measured by a conventional method. The present inventor has found that using a micron-sized active material is advantageous for improving the Coulomb efficiency of the material.

[0052] The silicon-based material according to the present invention may be porous silicon particles, for example, porous amorphous silicon particles and / or porous polycrystalline silicon particles. The particle diameter of the porous silicon particles according to the present invention is preferably 500 nm to 50 μm, more preferably 1 to 5 μm. By using micron-sized porous silicon particles, it is advantageous for improving the Coulomb efficiency of the material.

[0053] The porous silicon particles according to the present invention can be provided by a porous silicon material. The porous silicon material can be prepared by using an alloy reaction of magnesium metal and silicon metal and a dealloying method by vacuum distillation. Hereinafter, the preparation method of the porous silicon material, other related equipment, and the method will be described.

[0054] The method for preparing a porous silicon material according to the present invention includes the following steps.

[0055] Step (i): Place the alloy material and silicon particles into a furnace, expel the air from the furnace, and fill with an inert gas. (ii) Heat the alloy material and silicon particles to 1000-1300°C, keep them warm for 1-6 hours, let them cool naturally, then remove the alloy and break it apart. (iii) The fragmented alloy is placed in a vacuum furnace, the gas inside the furnace is discharged, the temperature is heated to 700-950°C, and vacuum distillation is performed to dealloy the material and obtain a porous silicon material. In step (i), an air pump may be used to discharge the air inside the furnace. The furnace pressure corresponds to 0.01% atmospheric pressure. The alloy material may contain at least one of zinc, magnesium, calcium, strontium, barium, boron, phosphorus, lithium, and iron. The silicon content in the alloy material and silicon particles is about 20 to 99 mol%. The mass ratio of silicon particles to alloy material may be 33:(40 to 90), preferably 33:(50 to 80), and more preferably 33:(60 to 70). The inert gas may be one or more selected from nitrogen gas, argon gas, helium gas, and neon gas. According to one embodiment of the present invention, the inert gas is argon gas.

[0056] In step (ii), the heating temperature is preferably 1100 to 1250°C, and more preferably 1100 to 1150°C. The holding time is preferably 2 to 5 hours, and more preferably 2 to 3 hours.

[0057] In step (iii), a molecular pump is used to remove all the gas from inside the furnace. For example, the furnace pressure is equivalent to 0.001% atmospheric pressure. The heating temperature is preferably 750 to 850°C, and more preferably 800 to 830°C.

[0058] The following explanation of alloy materials will use metallic magnesium.

[0059] (i) Place metallic magnesium and silicon particles into a molten furnace, evacuate the furnace air, and then fill with argon gas as an inert protective atmosphere.

[0060] (ii) The magnesium and silicon particles are heated to 1000-1300°C, kept warm for 1-6 hours, and after natural cooling, the magnesium-silicon alloy is removed and crushed.

[0061] (iii) The shattered magnesium-silicon alloy is placed in a vacuum furnace, the furnace gas is discharged, the temperature is heated to 700-950°C, and vacuum distillation is performed to dealloy the material and obtain a porous silicon material.

[0062] Porous silicon particles are formed by polishing a porous silicon material. Polishing may be done by ball milling. The mill balls used in the ball mill may be zirconia balls. The diameter of the mill balls may be 0.5 to 5 cm, preferably 1 to 3 cm. The ratio of balls to material may be (3 to 9):1, preferably (4 to 8):1, and more preferably (5 to 7):1. The ball mill may be operated at a rotation speed of 200 to 700 rpm, preferably 300 to 500 rpm. The ball milling time may be 0.5 to 5 hours, preferably 1 to 3 hours, and more preferably 1.5 to 2 hours.

[0063] In some embodiments, a porous silicon material is placed in a zirconia ball mill jar, zirconia balls are added in a weight ratio of 1:5 to 6 (material:balls), and the material is polished at a rotation speed of 300 to 500 rpm for 1.5 to 2 hours to obtain porous silicon particles with a particle size of 1 to 5 μm.

[0064] In one broad configuration, the present invention is Apparatus for forming an alloy by alloying silicon particles and alloying material (i), Apparatus for casting alloys into alloy sheets, strips, or films (ii), Apparatus for extracting alloy material from alloy sheets, strips, or films to form porous silicon material (iii), The present invention provides equipment for preparing porous silicon materials from silicon particles containing [a specific substance].

[0065] In another broader configuration, the present invention is (i) A step of forming an alloy by alloying at least one of silicon raw materials and aluminum raw materials with an alloying material, (ii) Casting the alloy into an alloy sheet, strip or film, (iii) Steps of extracting the alloy sheet, strip or film to form at least one of the porous silicon sheet, strip or film and the porous aluminum sheet, strip or film, (iv) Interacting at least one of a porous silicon sheet, strip or film and a porous aluminum sheet, strip or film with an aqueous solution to generate hydrogen gas through the interaction. A method for preparing hydrogen gas containing [a specific substance].

[0066] In step (i), the alloy material may contain at least one of zinc, magnesium, calcium, strontium, barium, boron, phosphorus, lithium, and iron. Other impurities in the alloy do not significantly affect the performance of the prepared hydrogen gas. Step (i) can produce an alloy containing about 20 to 99 mol% silicon. Preferably, step (i) can produce an alloy containing about 60 mol% silicon.

[0067] In another broader definition, the present invention relates to a porous silicon sheet, strip or film for preparing hydrogen gas in interaction with a solution containing H2O, and a method for preparing at least one of a porous aluminum sheet, strip or film. (i) A step of forming an alloy by alloying at least one of silicon raw materials and aluminum raw materials with an alloying material, (ii) casting the alloy into an alloy sheet, strip or film, (iii) Extracting the alloy sheet, strip or film to form at least one of the porous silicon sheet, strip or film and the porous aluminum sheet, strip or film, This provides a method that includes this.

[0068] The aforementioned solution containing H2O may be substantially basic.

[0069] In another broader configuration, the present invention is (i) A step of forming an alloy by alloying at least one of silicon raw materials and aluminum raw materials with an alloying material, (ii) Casting the alloy into an alloy sheet, strip or film, (iii) Steps of extracting the alloy sheet, strip or film to form at least one of the porous silicon sheet, strip or film and the porous aluminum sheet, strip or film, (iv) A step of interacting at least one of the porous silicon sheet, strip or film and the porous aluminum sheet, strip or film with an aqueous solution to generate hydrogen gas by the interaction, wherein the aqueous solution is preferably substantially basic. The present invention provides a method for preparing hydrogen gas containing [a specific substance].

[0070] In another broader configuration, the present invention relates to equipment for producing at least one of porous silicon sheets, strips or films and porous aluminum sheets, strips or films, wherein at least one of the porous silicon sheets, strips or films and porous aluminum sheets, strips or films is arranged to generate hydrogen gas through interaction with an aqueous solution, and the equipment is Apparatus (i) for forming an alloy by alloying at least one of silicon raw materials and aluminum raw materials with an alloying material, Apparatus for casting alloys into alloy sheets, strips, or films (ii), (iii) Apparatus for extracting alloy sheets, strips, or films to form at least one of porous silicon sheets, strips, or films, and porous aluminum sheets, strips, or films, We provide equipment including the following.

[0071] In another broader configuration, the present invention provides equipment for preparing hydrogen gas, including equipment for generating hydrogen gas by having at least one of a porous silicon sheet, strip or film and a porous aluminum sheet, strip or film interact with an aqueous solution.

[0072] Furthermore, the present invention is (i) A step of forming an alloy by alloying at least one of silicon raw materials and aluminum raw materials with an alloying material, (ii) casting the alloy into an alloy sheet, strip or film, (iii) Extracting the alloy sheet, strip or film to form at least one of the porous silicon sheet, strip or film and the porous aluminum sheet, strip or film, Porous silicon sheets, strips, or films, and at least one of porous aluminum sheets, strips, or films can be produced by a method including the above.

[0073] Figure 1 shows the X-ray diffraction measurement results after heat treatment of an embodiment of a material containing silicon, calcium, potassium, zirconium, and oxygen, and the formed substance is potassium feldspar.

[0074] In some embodiments, the active material is a material arranged to hold a certain amount of metal ions in order to store electrical energy. For example, the active material may be porous silicon or metalloid (MeO) prepared in the manner described above, or a silicon-based material SiO x(Here, 0 < x < 2), and / or it may be a high-capacity silicon-based material having a plurality of sites that can accept a certain amount of metal ions (e.g., Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, Ti, La, Ce, Hf ions) through a suitable chemical reaction between the active material and the metal ions.

[0075] During the "charging" period (where current / electrons are supplied from outside), lithium ions adhere to the pores of silicon in the active material to form an Si / Li alloy, so lithium is inserted into the active material. Conversely, during the "discharging" process (where the material supplies electrons / current to the equipment it is connected to), lithium ions separate from the Si / Li alloy. The electrolyte in contact with the active material can supply lithium ions.

[0076] As an example, the active material includes one or more metal elements (e.g., Zn, Ga, In, Sn, Pb, and Bi), one or more metal oxides (e.g., ZnO, Ga2O3, Ga2O, In2O3, SnO, SnO2, PbO, Pb3O4, PbO2, Pb2O3, Pb 12 O 19 , Bi2O3), alloys of one or more of these metal elements, and / or conversion-type materials, but are not limited thereto. In battery applications, these materials can react with metal elements to store or release energy (preferably electrical energy).

[0077] During the "charging" process, lithium ions adhere to the metal oxide in the active material and embed lithium into the active material by converting the metal oxide into lithium oxide and a lithium metal alloy. During the "discharging" process, lithium ions are extracted into the electrolyte and the metal is converted into a metal oxide.

[0078] The preloaded raw material contains one or more metal atoms preloaded into the active material by a treatment process. The precursor of the metal atom is preferably at least one of the forms of elemental metal (A), metal oxide (A-O), metal hydroxide (A-OH), metal acetate (A-CH3COOH), metal nitrate (A-NO3), metal sulfate (A-SO4), and metal carbonate (A-CO3). The precursor of the metal atom contains one or more metal atoms selected from Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, Ti, La, Ce, and Hf.

[0079] The preloaded metal atoms serve as an "adhesive" for the active material, adhering multiple separate parts of the active material. The metal atoms can form a complex with the active material and bond the oxygen atoms of the active material within the complex.

[0080] For example, the empirical formula of the material according to the present invention is A y MeO x (where A is one or more selected from metal atoms consisting of Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, Ti, La, Ce, Hf, Me is a metalloid such as Si, B, O is oxygen, 0 < x < 4, and 0 < y < 4). The size of the basic particles of the material according to the present invention may be 5 nm to 5 mm.

[0081] In particular, the preloaded metal atoms hold oxygen atoms of SiO x (where 0 < x < 2) within each part of the active material, and can deactivate the oxygen atoms of SiO x (0 < x < 2) and SiO2 within each part of the active material. Each of the metal atoms and oxygen atoms shares an electron pair between them to form a covalent bond. Since the metal atoms are bonded to the oxygen atoms, during the battery charging period and / or discharging period, the metal atoms remain bonded to the oxygen atoms of the active material.

[0082] The structure of the complex is described in detail below, and the active material forms a complex with metal atoms and oxygen atoms. In this complex, the atoms are arranged in an orderly or disordered manner, which leads to the formation of polycrystalline or amorphous regions within the preloaded raw material. Therefore, the preloaded raw material supporting the metal atoms becomes an amorphous or polycrystalline material. The resulting material containing the A-Me-O compound is unreactive in an atmospheric environment.

[0083] By retaining oxygen atoms with preloaded metal atoms and deactivating the oxygen atoms, the material according to the present invention can significantly improve the Coulomb efficiency.

[0084] <Method for preparing battery materials> A method for a battery material according to the present invention includes the step of preloading one or more types of metal atoms into an active material, wherein the active material is arranged to undergo a chemical reaction during the charging and / or discharging periods of the battery, and the metal atoms are arranged to retain one or more oxygen atoms on the surface of the active material and to deactivate one or more oxygen atoms on the surface of the active material during the charging and / or discharging periods of the battery.

[0085] Taking a metalloid (Me)-based material as an example, several metal atoms (A) selected from Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, Ti, La, Ce, and Hf are preloaded into the material's structure. The metal atoms (A) react with oxygen (O) on the surface of the metalloid (Me)-based material and can form an A-Me-O complex (i.e., an oxidized state) with the metalloid (Me). In this complex, the metal atoms deactivate the oxygen. This reduces the effect of oxygen and solves the problem of low Coulomb efficiency. Therefore, this can improve the electrochemical performance of metalloid materials when used in batteries.

[0086] In some embodiments, the metal atoms are preloaded onto the active material by the following method: annealing the active material and the material containing the metal atoms in an atmosphere selected from helium, nitrogen, and argon at an annealing temperature of 500°C to 1200°C. In the above-described method, the material containing the metal atoms is a metal salt or a metal oxide. The metal salt may be a carbonate, nitrate, acetate, or sulfate. The annealing temperature is preferably 800°C to 1150°C, and more preferably 1000°C to 1100°C. The present invention has found that increasing the annealing temperature appropriately improves the Coulomb efficiency of the battery.

[0087] In some other embodiments, the metal atoms are preloaded onto the active material in the following manner.

[0088] Specifically, the active material and the material containing the metal atoms are subjected to ball milling or high-energy ball milling, and after mixing the active material and the material containing the metal atoms, the mixture is heat-treated in at least one atmosphere selected from helium gas, nitrogen gas, and argon gas. In the method described above, the material containing the metal atoms is a metal salt or a metal oxide. The metal salt may be a carbonate, nitrate, acetate, or sulfate. The heat treatment temperature may be 500°C to 1200°C, preferably 800°C to 1150°C, and more preferably 1000°C to 1100°C. The inventors have found that the Coulomb efficiency of the battery is improved by appropriately increasing the heat treatment temperature.

[0089] <Battery and preparation method> The material according to the present invention is used in batteries. Examples of batteries include, but are not limited to, lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, calcium-ion batteries, magnesium-ion batteries, and lithium-sulfur batteries. Preferably, the material according to the present invention is used as a negative electrode material in a battery.

[0090] In some embodiments, exemplary battery structures are provided, comprising a negative electrode, a positive electrode, and an electrolyte in communication with the positive and negative electrodes, each made of a material according to the present invention, wherein ions can move through the electrolyte during a charge-discharge cycle. The battery according to the present invention may include a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode is made of a material according to the present invention, and the electrolyte is in ionic communication with the negative electrode and the positive electrode. In some embodiments, during the charging period of the battery, metal ions from the positive electrode move to the negative electrode, and during the discharging period of the battery, the metal ions return to the positive electrode. During the discharging period of the battery, the metal ions are not trapped by oxygen atoms in the negative electrode.

[0091] Optionally, the battery may include a separator, which is provided to electrically insulate the positive and negative electrodes. The positive electrode is suitable for releasing metal ions such as lithium, sodium, potassium, calcium, and magnesium ions. The negative electrode, on the other hand, receives metal ions from the positive electrode.

[0092] During each "charge" cycle of a battery, metal ions (e.g., lithium, sodium, potassium, calcium, and magnesium ions) move from the positive electrode to the negative electrode. Then, during the "discharge" phase, the metal ions present at the negative electrode are returned to the positive electrode.

[0093] Advantageously, in the metal ion discharge process, the metal atoms preloaded onto the material according to the present invention, which serves as the negative electrode, play a crucial role. Since the oxygen atoms at the negative electrode bind to the preloaded metal atoms, during the battery discharge period, the metal ions are not trampled by the oxygen atoms at the negative electrode, and the dissolution of the active material into the electrolyte is suppressed.

[0094] The battery can be manufactured using conventional methods. The materials according to the present invention, conductive carbon black and sodium carboxymethylcellulose, are mixed, and an appropriate amount of deionized water, which is a solvent, is added and mixed until uniform to prepare a slurry. This slurry is evenly applied to copper foil with a spatula, dried in a vacuum, and then a circular electrode sheet is punched out using a mold. This circular electrode sheet and a metallic lithium sheet are used to assemble a battery.

[0095] Next, the following tests were conducted on the manufacturing process and materials according to the present invention, with specific examples. Unless otherwise specified, the test methods used in the following examples and comparative examples are conventional methods. Unless otherwise specified, all materials, reagents, etc., used in the following examples and comparative examples are commercially available.

[0096] The testing method is described below.

[0097] SEM: The morphology of the powder is examined using a scanning electron microscope (SEM, Philips XL30FEG).

[0098] XRD: The test is performed using an X-ray diffractometer (XRD, D2 Phaser Brucker). The scanning range is 10° to 80°, the scanning speed is 0.05° / s, and the X-ray source is CuKα (λ = 0.154178 nm).

[0099] Electrical performance test: The materials obtained in the examples or comparative examples, conductive carbon black (Acetylene Black) and sodium carboxymethylcellulose, are mixed in a mass ratio of 8:1:1. An appropriate amount of deionized water, which is the solvent, is added, and the mixture is uniformly mixed in an agate mortar to prepare a slurry. The slurry is uniformly applied to copper foil with a spatula, dried at 80°C in a vacuum for 4 hours, and then a circular electrode sheet with a diameter of 16 mm is punched out using a mold. This circular electrode sheet is used as the target electrode, and a metallic lithium sheet is used as the counter electrode, and the two are assembled into a 2032 type button cell in a glove box.

[0100] Electrochemical tests were conducted using the Neware battery testing system, with a charge / discharge current density of 250 mA / g, a charge / discharge cutoff voltage of 0.01 to 1 V, and a test temperature of 25°C. Example 1 67g of magnesium and 33g of silicon particles were placed in a high-temperature molten furnace. An air pump was used to remove the air from the furnace to 0.01% atmospheric pressure, and the furnace was filled with 99.99% pure argon gas as an inert protective atmosphere.

[0101] Magnesium and silicon particles were heated to 1100°C, kept warm for 2 hours, and then allowed to cool naturally before the magnesium-silicon alloy was extracted and crushed.

[0102] The crushed magnesium-silicon alloy was placed in a vacuum furnace, the gas inside the furnace was removed to 0.001% atmospheric pressure using a molecular pump, the temperature was heated to 800°C, and dealloying was performed by vacuum distillation to obtain a porous silicon material.

[0103] 10 g of porous silicon material was placed in a 50 ml zirconia ball mill jar, 60 g of 1 cm diameter zirconia balls were added, and the mixture was polished at 400 rpm for 1.5 hours to obtain porous silicon particles with a particle size of 1 to 5 μm. Figure 1 is an SEM image of the porous silicon particles. As can be seen from Figure 1, the porous silicon particles had an irregular polygonal shape, a particle size of 1 to 5 μm, and few nanoparticles. Due to the porous structure of the silicon particles, the mechanical strength was reduced, and even with a low-energy ball mill, the particles were pulverized to obtain a powder with a relatively uniform particle size. Figure 2 is a pore size distribution diagram of the porous silicon particles. The following examples and comparative examples all obtained porous silicon particles with similar performance using the above method.

[0104] A composite material was obtained by placing 0.4g of calcium oxide, 0.4g of potassium oxide, and 1g of zirconia into a ball mill jar and performing ball milling under an argon atmosphere.

[0105] The composite material was heated to 1100°C under an argon atmosphere and kept warm for 3 hours to obtain a material for batteries. The electrical performance of the obtained material is shown in Table 1.

[0106] Figure 3 is an XRD diagram of the battery material obtained in this embodiment. Figure 3 shows a peak in the compound formed by metal atoms A and the elemental silicon oxide layer, indicating that a solid-state chemical reaction occurred between the metal atoms and the elemental silicon oxide layer, thus proving that the present invention has succeeded in preparing an A-Si-O porous silicon composite material.

[0107] Example 2 67g of magnesium and 33g of silicon particles were placed in a high-temperature molten furnace. An air pump was used to remove the air from the furnace to 0.01% atmospheric pressure, and the furnace was filled with 99.99% pure argon gas as an inert protective atmosphere.

[0108] Magnesium and silicon particles were heated to 1100°C, kept warm for 2 hours, and then allowed to cool naturally before the magnesium-silicon alloy was extracted and crushed.

[0109] The crushed magnesium-silicon alloy was placed in a vacuum furnace, the gas inside the furnace was removed to 0.001% atmospheric pressure using a molecular pump, the temperature was heated to 800°C, and dealloying was performed by vacuum distillation to obtain a porous silicon material.

[0110] 10 g of porous silicon material was placed in a 50 ml zirconia ball mill jar, 60 g of 1 cm diameter zirconia balls were added, and the mixture was polished at a rotation speed of 400 rpm for 1.5 hours to obtain porous silicon particles with a particle size of 1 to 5 μm.

[0111] A composite material was obtained by adding 1 g of yttrium oxide to a ball mill jar and ball milling it under an argon atmosphere.

[0112] The composite material was heated to 1100°C in an argon atmosphere and kept warm for 3 hours to obtain a material for batteries. The electrical performance of the obtained material is shown in Table 1.

[0113] Figure 4 is an XRD diagram of the battery material obtained in this embodiment. Figure 4 shows picks of the compound formed from metal atoms A and elemental silicon oxide layers, indicating that a solid-state chemical reaction occurred between the metal atoms and the elemental silicon oxide layer, thus proving that the present invention has succeeded in preparing an A-Si-O porous silicon composite material.

[0114] Example 3 67g of magnesium and 33g of silicon particles were placed in a high-temperature molten furnace. An air pump was used to remove the air from the furnace to 0.01% atmospheric pressure, and the furnace was filled with 99.99% pure argon gas as an inert protective atmosphere.

[0115] Magnesium and silicon particles were heated to 1100°C, kept warm for 2 hours, and then allowed to cool naturally before the magnesium-silicon alloy was extracted and crushed.

[0116] The crushed magnesium-silicon alloy was placed in a vacuum furnace, the gas inside the furnace was removed to 0.001% atmospheric pressure using a molecular pump, the temperature was heated to 800°C, and dealloying was performed by vacuum distillation to obtain a porous silicon material.

[0117] 10 g of porous silicon material was placed in a 50 ml zirconia ball mill jar, 60 g of 1 cm diameter zirconia balls were added, and the mixture was polished at a rotation speed of 400 rpm for 1.5 hours to obtain porous silicon particles with a particle size of 1 to 5 μm.

[0118] A composite material was obtained by adding 0.5g of alumina and 0.5g of potassium oxide to a ball mill jar and ball milling it under an argon atmosphere.

[0119] The composite material was heated to 1100°C in an argon gas atmosphere and kept warm for 3 hours to obtain a material for batteries. The electrical performance of the obtained material is shown in Table 1.

[0120] Figure 5 is an XRD diagram of the battery material obtained in this embodiment. Figure 5 shows picks of the compound formed from metal atoms A and a layer of elemental silicon oxide, indicating that a solid-state chemical reaction occurred between the metal atoms and the elemental silicon oxide layer, thus proving that the present invention has succeeded in preparing an A-Si-O porous silicon composite material.

[0121] Comparative Example 1 A composite material was obtained by placing 10g of nanosilicon material (approximately 100nm in diameter) into a 50ml zirconia ball mill jar, adding 60g of 1cm diameter zirconia balls, adding 1g of yttrium oxide to the ball mill jar, and polishing in an argon atmosphere at 400rpm for 1.5 hours.

[0122] The composite material was heated to 1100°C in an argon gas atmosphere and kept warm for 3 hours to obtain a material for batteries. The electrical performance of the obtained material is shown in Table 1.

[0123] Comparative Example 2 67g of magnesium and 33g of silicon particles were placed in a high-temperature molten furnace. An air pump was used to remove the air from the furnace to 0.01% atmospheric pressure, and the furnace was filled with 99.99% pure argon gas as an inert protective atmosphere.

[0124] Magnesium and silicon particles were heated to 1100°C, kept warm for 2 hours, and then allowed to cool naturally before the magnesium-silicon alloy was extracted and crushed.

[0125] The crushed magnesium-silicon alloy was placed in a vacuum furnace, the gas inside the furnace was removed to 0.001% atmospheric pressure using a molecular pump, the temperature was heated to 800°C, and dealloying was performed by vacuum distillation to obtain a porous silicon material.

[0126] 10 g of porous silicon material was placed in a 50 ml zirconia ball mill jar, 60 g of 1 cm diameter zirconia balls were added, and the mixture was polished at 400 rpm for 1.5 hours to obtain porous silicon particles with a particle size of 1 to 5 μm. The electrical properties of the obtained porous silicon particles are shown in Table 1.

[0127] Comparing Examples 1-3 with Comparative Example 2, preloading metal atoms can improve the initial Coulomb efficiency by approximately 2%, and even up to approximately 4%. Such a wide improvement is already remarkable in this field. Therefore, preloading metal atoms, which are the negative electrode material, into the active material is not something that a person skilled in the art would easily conceive. Comparing Example 2 with Comparative Example 1, using micron-sized porous silicon particles instead of nanosilicon material is advantageous in significantly improving the initial Coulomb efficiency and the initial charge and discharge capacities. In light of these excellent technical effects, using micron-sized porous silicon particles instead of nanosilicon material is not a conventional option in this art. As is clear from Table 1, a battery using the material according to the present invention as the negative electrode has high Coulomb efficiency and electrical capacity, and therefore has excellent electrochemical performance.

Claims

1. An active material arranged to cause a chemical reaction during the charging and / or discharging period of the battery, One or more metal atoms arranged to retain one or more oxygen atoms of the active material and to deactivate one or more oxygen atoms of the active material during the charging and / or discharging period of the battery, Includes, The active material is a porous Si material, the active material is particulate, and the particle size of the active material is 1 μm to 5 μm. A material for the negative electrode of a lithium-ion battery, characterized by the following features.

2. The material according to claim 1, characterized in that the metal atoms form a complex with the active material.

3. The material according to claim 2, characterized in that the metal atoms are arranged within the complex so as to bond to oxygen atoms on the surface of the active material.

4. The material according to claim 3, characterized in that the metal atoms are bonded to oxygen atoms on the surface of the active material by covalent bonds.

5. The material according to claim 4, characterized in that the metal atoms remain bonded to the oxygen atoms during the charging and / or discharging periods of the battery.

6. The material according to claim 5, characterized in that the metal atom reacts with the oxygen atom to form an oxide within the complex.

7. The material according to claim 6, characterized in that the oxide forms at least one of an amorphous material and a polycrystalline material.

8. The material according to claim 7, characterized in that the metal atoms retain the oxygen atoms and deactivate the oxygen atoms, thereby improving the Coulomb efficiency of the material.

9. The material according to claim 1, characterized in that the metal atom is one or more selected from Na, K, Rb, Cs, Ca, Al, Mg, Sr, Sc, Y, Zr, Ti, La, Ce, and Hf.

10. The material according to claim 9, characterized in that the metal atoms are embedded in the active material such that they hold the oxygen atoms and deactivate the oxygen atoms.

11. The material according to claim 10, characterized in that the metal atoms are embedded in the active material as at least one of elemental metals, metal oxides, metal hydroxides, metal acetates, metal nitrates, metal sulfates, and metal carbonates.

12. The active material is SiO ｘ (Here, 0 < x < 2) and SiO ２ The material according to claim 11, characterized in that it includes at least one of the following.

13. A battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode is made of a material described in any one of claims 1 to 12, and the electrolyte is in ionic communication with the negative electrode and the positive electrode.

14. The battery according to claim 13, characterized in that during the charging period of the battery, the metal ions in the positive electrode move to the negative electrode, and during the discharging period of the battery, the metal ions return to the positive electrode.

15. The battery according to claim 14, characterized in that the metal ions are not trapped by oxygen atoms in the negative electrode during the discharge period of the battery.

16. The battery according to claim 15, characterized in that the metal ions are one or more selected from Li, Na, K, Ca, and Mg.

17. A step of preloading one or more types of metal atoms into an active material, wherein the active material is arranged to undergo a chemical reaction during the charging and / or discharging periods of the battery, and the metal atoms are arranged to retain one or more oxygen atoms on the surface of the active material and to deactivate one or more oxygen atoms on the surface of the active material during the charging and / or discharging periods of the battery. A method for preparing the material according to any one of claims 1 to 12, characterized by including the following.

18. A method of preloading the metal atoms into the active material by annealing the active material and the material containing the metal atoms in an atmosphere selected from helium gas, nitrogen gas, and argon gas at an annealing temperature of 500°C to 1200°C, The method according to claim 17, characterized by preloading one or more types of metal atoms into an active material.

19. The method according to claim 18, characterized in that increasing the annealing temperature improves the Coulomb efficiency of the battery.

20. The method involves processing the active material and the material containing the metal atoms in a high-energy ball mill, mixing the active material and the material containing the metal atoms, and then heat-treating them in at least one atmosphere selected from helium gas, nitrogen gas, and argon gas. The method according to claim 19, characterized in that the metal atoms are preloaded onto the active material.

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