WO2017058061A1

WO2017058061A1 - Electrode material for rechargeable metal-ion batteries and method of producing same

Info

Publication number: WO2017058061A1
Application number: PCT/RU2016/050030
Authority: WO
Inventors: Станислав Сергеевич ФЕДОТОВ; Нелли Ракиповна ХАСАНОВА; Александр Шайлович САМАРИН; Евгений Викторович АНТИПОВ
Priority date: 2015-09-28
Filing date: 2016-09-08
Publication date: 2017-04-06
Also published as: RU2619600C2; RU2015141117A

Abstract

The invention relates to electrical engineering, and more particularly to the development of a novel type of electrode material based on fluorophosphates of transition and alkali metals for rechargeable metal-ion batteries for use in large-scale devices in alternative energy sources. Proposed is an electrode material having the formula A(M_1-xM'_x)PO₄(F_1-yO_y) with a potassium titanyl phosphate (KTP) crystal structure, where A is an alkali metal, M is a transition metal, and M' is a metal used as a modifying additive, where 0≤х≤0.3; 0≤у≤1, said material having a specific energy of more than 600 Wh/kg and being capable of functioning at cycling rates greater than 10C with a change in volume of no more than 5% during cycling.

Description

ELECTRODE MATERIAL FOR METAL-ION BATTERIES, METHOD OF ITS PRODUCTION, ELECTRODE AND BATTERY BASED ON

ELECTRODE MATERIAL

Technical field

The invention relates to electrical engineering, namely to the development of a new type of electrode material based on transition and alkali metal fluoride phosphates for metal-ion batteries for use in large-sized devices in alternative energy.

State of the art

Chemical current sources - batteries - are widespread in various fields of human activity. The main objective of the battery is to provide energy to devices in the absence of direct access to energy networks. In particular, thanks to lithium-ion batteries, the emergence of modern portable electronics has become possible: smartphones, laptops, and laptops. The main components of the battery, limiting the specific energy characteristics, are electrode materials.

Currently, the batteries used in mobile devices use materials based on layered oxides LiM0 ₂ (M = Mn, Co, Ni). However, despite the relatively high specific capacity, these materials cannot be used in large-scale applications, such as stationary energy storage devices or electric vehicles, due to safety problems associated with the instability of the crystal structure. During the operation of such materials, especially during irregular charging or recharging, active oxygen may be released, resulting in ignition of the electrolyte and subsequent destruction of the battery.

The most common electrode material for large-sized devices is LiFeP0 ₄ with an olivine structure, the specific energy consumption of which is 583 Wh / kg. The main disadvantages of this material are associated with a low working potential and, as a consequence, low energy intensity, as well as a rather large change in volume during the cycling process of ~ 7%. In addition, LiFeP0 ₄ has low power indices, which are due to the two-phase mechanism of de / intercalation of Li ⁺ ions. Known electrode material Li ₃ V2 (P0 ₄ ) 3 having high ionic conductivity, which is the main candidate as a cathode material for high-power devices. However, this material undergoes a significant change in volume during cycling (about 8%), which can negatively affect the degradation stability of the material [Rui, X., Yan, Q., Skyllas-Kazacos, M., Lim, T. M. (2014 ) Journal of Power Sources 258, 19 - 38].

Known electrode material LiFeS0 ₄ F with the structure of potassium titanyl phosphate (KTP). However, this material has a low energy intensity of 558 Wh / kg, which reduces its attractiveness for use in large-sized devices. Moreover, for this connection there is no data on power characteristics. [Recham, N .; Gwenaelle, R .; Sougrati, M. T .; Chotard, J.-N .; Frayret, C; Mariyappan, S .; Melot, B. C; Jumas, J.-C; Tarascon, J.-M. (2012) Chem. Mater., 24, 4363-4370].

Closest to the claimed invention is a material based on LiVP0 ₄ F with the structure of tavorite (US 6645452 In 1). Possessing comparable values of specific energy intensity, LiVP0 ₄ F cathode materials with an energy intensity of 655 Wh / kg have a serious design flaw - a large volume change during charge-discharge processes — 8.5% [Ellis, B. L., Ramesh, T. N. , Davis, LJ M., Goward, GR & Nazar, LF (2011). Chem. Mater. 23, 5138-5148]. In this regard, the stable cycling of this material in the long term (more than 500-1000 cycles) is called into question. In addition, this type of material has very low kinetic characteristics, namely the diffusion coefficients of Li ⁺ ions

-12 -18 2

are 10 ^" - 0 ^~ cm / s, which prevents its use in high power devices [Xiao, PF, Lai, M.O., Lu L. (2013), Solid State Ionics, 242, 10-19].

Disclosure of invention

The objective of the present invention was to create an electrode material with a unique combination of structure and elemental composition, providing a specific energy consumption of more than 600 Wh / kg, capable of operating at cycling speeds above 10 ° C and volume change during cycling not exceeding 5%, i.e. oriented to use in devices for energy storage, including high-power current sources with increased specific energy.

The problem is achieved in that as an electrode material for metal-ion batteries used material based on transition and alkali metal fluoride phosphates with the general formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ) with a crystal structure of "potassium-titanyl- phosphate "(KTR), not previously used in combination with the indicated chemical composition in materials for metal-ion batteries, where A is an alkali metal, M is a transition metal, M 'is a metal used as a modifying additive, where 0 <x <0.3; 0 <y <1.

Preferably, alkali metal (A) is Li and / or Na, and / or K, and / or Rb.

Preferably, Ti, V, Nb, Cr, Mo, Mn, Fe or a mixture thereof is used as the transition metal (M).

Preferably, Mg, Zn, Al, Ga or a mixture thereof is used as a modifying additive (Μ ').

The task is also achieved by a method of producing an electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ), where K and / or Rb acts as an alkali metal (A), including the production of phosphate Mi_ _x M' _x O _y P0 ₄ by freeze drying, followed by annealing or ceramic synthesis, followed by mixing the obtained phosphate with AF, AHF ₂ , A ₂ C0 ₃ or a mixture of H ₄ F and A ₂ C0 ₃ and annealing the resulting mixture.

The problem is achieved by the method of obtaining an electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_yOy), where Li and / or Na acts as an alkali metal (A), or a mixture with K and / or Rb, including obtaining an electrode material formulas A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ), where K and / or Rb acts as the alkali metal (A), followed by complete or partial replacement of K and / or Rb with Li and / or Na.

Preferably, the substitution of K and / or Rb with Li and / or Na is carried out using ion exchange or electrochemical substitution.

The technical result from the use of the proposed technical solution lies in the fact that the obtained electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ) with a crystal structure of potassium titanyl phosphate (KTP), where A represents alkali metal, M is a transition metal, M 'is a metal used as a modifying additive, where 0 <x <0.3; 0 <y <1, which has a specific energy consumption of more than 600 Wh / kg, is capable of operating at cycling speeds above 10 ° C with a volume change during cycling not exceeding 5%.

The proposed electrode material with a potassium titanyl phosphate (KTP) crystal structure can be classified as high-power electrode materials capable of stable operation at high cycling rates of 10 ^ -40C (discharge time 5 minutes - 90 seconds, respectively) with a preservation of more than 50% from the original specific capacity (material with a particle size of the order of 300 nm). Achieve data values of specific capacitance at such high currents allow high kinetic characteristics of this material, namely the diffusion coefficients Li ⁺ , on average equal to 10 - ^" 9 - O - ^" 13 cm 2 / s, which is achieved due to the specific crystal structure of the materials, which is durable a three-dimensional framework constructed from Mi_ _x M ' _x 06-2 _y F2y and P0 ₄ polyhedra and forming volumetric extended channels containing mobile A ⁺ ions capable of rapid migration.

The advantages of the proposed electrode material include a small change in volume during electrochemical charge-discharge processes. For a material with the composition AVP0 ₄ F, this indicator was ~ 3%, which makes it possible to repeatedly cycle it (more than 1000 cycles) without significant mechanical deformations leading to destruction of the electrode. Another advantage of the described electrode material is the high ionic conductivity characteristic of this structural type (up to 10 ^"4 -10 ^{" 5} S / cm).

In terms of energy intensity, this electrode material is not inferior to known analogues, such as LiVP0 ₄ F with tavorite structure (655 Wh / kg) and surpasses many others, such as LiFeP0 ₄ with olivine structure (583 Wh / kg). Energy intensity of the proposed electrode material of composition AVP0 ₄ F is 600-H560 Wh / kg. The volumetric energy density of a new electrode material with a KTP structure is slightly lower in comparison with some known analogues (-2040 Wh / L versus 2135 Wh / L for LiFeP0 ₄ and 2140 Wh / L for LiVP0 ₄ F with a tavorite structure), however, in many areas of application associated with large-sized devices (for example, in alternative energy), this characteristic is not critical.

By varying the chemical composition, the declared electrode material exhibits electrochemical activity in different ranges of potential values: at a potential value above 3.0 V (relative to Li / Li ⁺ ), the material acts as a cathode, at a potential value below 2.5 V it exhibits the properties of the anode material.

To confirm the receipt of the indicated technical result, samples of the declared electrode material of the formula A (M ₁ _ _x M ' _x ) P0 ₄ (F ₁ _ _y O _y ), namely KVP0 ₄ F, KV _0.9 Alo, were made _. iP0 ₄ F, RbVP0 ₄ F, KV ₀ .75Cr _0.25 PO ₄ F, KVPC F ₀ .5O0.5, KTiP0 ₄ F, LiVP0 ₄ F, etc., are analyzed by the spectrum of physicochemical methods necessary for the art. The phase composition was determined by X-ray phase analysis (XRD) using a Bruker D2 PHASER diffractometer with Cu-Κα radiation and λ = 1.5406 A. All samples obtained are single-phase.

The chemical composition of the samples was confirmed by inductively coupled plasma atomic emission spectroscopy (AES-IP) using an Agilent ICP-OES 5100 spectrometer (Agilent Technologies) and a local X-ray spectral analysis using a transmission electron microscope (PEM-LRSA) with correction of the abbreviation Titan G3 at operating voltage 120 kV. So, for example, in the KVP0 ₄ F material, the K: V: P ratio is 1.00 (5): 1.10 (8): 1.13 (5), which corresponds within the permissible error to the chemical formula ascribed.

Particle morphology of the above materials was studied by scanning electron microscopy (SEM) on a Carl Zeiss NVision 40 instrument using a LaB ₆ field emission cathode and an In-Lens detector at an accelerating voltage of 10–20 kV. Particles of the material have an oval shape with linear dimensions of 100- ^ 500 nm. The residual carbon content in the samples was determined by thermogravimetry (TG) in an air atmosphere using a thermal analyzer TG-DSC STA-449 apparatus (Netzsch, Germany) and does not exceed 5% of the mass.

The crystal structure of the samples was determined by the Rietveld method. It is shown that the claimed electrode material crystallizes in rhombic syngony. So, for example, for a material with the formula KVP0 ₄ F (space group # 33 Pna2i) the unit cell parameters are: a = 12.8201 (3) A, b = 6.3957 (2) A, c = 10.6118 (2) A and = 870.10 (3 ) A ³ ; χ = 1.59, R _p = 5.11%, R _wp = 6.69% (Fig. 1).

The crystal structure of the electrode material of the claimed formula is constructed from the connected vertices of the таι_ _χ 0 ' _χ 0 ₄ соедин 2 (X = F, O) octahedra, forming zigzag chains, interconnected by P0 ₄ tetrahedra into a strong three-dimensional framework, in the extended cavities of which there are alkali metal atoms . Depending on the nature of the mobile ion, in these materials one can observe a one-dimensional (in the case of rubidium and potassium or their mixtures with sodium or lithium) or a three-dimensional (sodium, lithium) system of diffusion channels, which is demonstrated by constructing valence bond forces (Fig. 2 ) The oxidation state Μι_ _χ Μ ' _{χ is} confirmed by the method of spectroscopy of characteristic electron energy losses (Fig. 3). The chemical formula of the material is shown by infrared spectroscopy on an Agilent Carry 630 FT-IR. the absence of adsorbed and / or crystallization H ₂ 0, as well as hydroxyl groups (Fig. 4).

To measure the electrochemical properties of the claimed electrode material, electrodes were prepared (Example 17), then two-electrode pressure cells were assembled (Example 18). As a result of the measurements, it was found that the claimed electrode material exhibits electrochemical activity in the potential ranges 1. (H5.1 V rel. Li / Li ⁺ depending on the chemical composition and can serve as a material for the positive electrode (cathode,> 3 V) and for the negative one (anode, <2.5 V). So, for example, a material of the formula KVP0 ₄ F demonstrates the properties of a high-voltage cathode material - potential range 3.0 ^ -4.8 V rel. Li / Li ⁺ , theoretical specific capacity 130 Ah / kg.

Electrochemical processes in the claimed electrode material are characterized by high flow rates. So for a material of the composition LiVP0 ₄ F, the diffusion coefficients of Li ⁺ ions calculated by the method of potentiostatic discontinuous titration are 10 –9-НО – 13 cm 2 / s, with a low polarization value of not more than 50 mV at a cycling rate of C / 10, and a small loss specific capacity with prolonged cycling -25% per 100 cycles at a cycling speed of 1C.

To confirm the energy intensity of the claimed electrode material, galvanostatic measurements were carried out at a current strength of C / 20. Integration of the obtained experimental dependence in the coordinates of potential (V) - specific capacity (Ah / kg) allows us to estimate the specific energy consumption (600-Н560 Wh / kg for the composition AVP0 ₄ F).

The performance of the inventive electrode material at cycling rates of 10 ^ -40C was demonstrated in a series of continuous galvanostatic measurements with a sequential increase in the discharge current from 1/10 to 40 equivalents C (Fig. 5-10). According to the test results, the electrode material stably holds more than 50% of the theoretical capacity at speeds higher than JS. Confirmation data is presented in FIG. 6 for KVP0 ₄ F and FIG. 9 for LiVP0 ₄ F.

Brief Description of the Drawings

The invention is illustrated by drawings.

In FIG. Figure 1 shows the X-ray diffraction pattern of the KVP0 ₄ F electrode material obtained using CuKa radiation (λ = 1.5406 A). The diffraction pattern is indicated in the rhombic syngony (space group Pna2i with parameters unit cell a = 12.8201 (3) A, b = 6.3957 (2) A, c = 10.6118 (2) A. The inset shows the crystal structure of KVP0 ₄ F corresponding to the structural type of KTP.

In FIG. Figure 2 shows the valence force maps for the electrode material A) of composition KVP0 ₄ F and B) of composition LiVP0 ₄ F. Blue (1) indicates the octahedra Mi_ _x M ' _x 0 ₆ -2yF2y, orange (2) indicates the tetrahedrons P0 ₄ , white spheres (3) - K ⁺ ions.

In FIG. Figure 3 shows the spectrum of characteristic electron losses (VL ₂ , 3-edge) for the electrode material of composition KVP0 ₄ F.

In FIG. 4 shows the IR spectrum of the electrode material composition KVP0 ₄ F.

In FIG. Figures 5–7 show the results of electrochemical testing of an electrode material of composition KVP0 ₄ F in a model cell in the potential range 2.0–4.7 V rel. Li / Li ⁺ , at room temperature, where in FIG. 5 shows galvanostatic cycling curves at a speed of C / 5; in FIG. 6 - bit curves at various cycling speeds; in FIG. 7 - dependence of the specific capacity on the cycle number at various cycling rates. The specific energy consumption of the material (Wh / kg) is defined as the product of the specific capacity (Ah / kg) by the average value of the potential (V).

In FIG. Figures 8–10 present the results of electrochemical testing of the electrode material of the composition LiVP0 ₄ F obtained by charging the initial KVP0 ₄ F electrodes to 4.8 V rel. Li / Li ⁺ at a speed of C / 20, keeping at this potential for 5 hours to remove K ⁺ ions and subsequent washing with dimethyl carbonate. Based on the obtained electrodes, model two-electrode cells were assembled, which were tested in the potential range 2.0 ^ -4.7 V rel. Li / Li ⁺ , at room temperature, where in FIG. 8 shows galvanostatic cycling curves at a speed of C / 5; in FIG. 9 - bit curves at various cycling speeds; in FIG. 10 - dependence of the specific capacity on the cycle number at various cycling speeds. The specific energy consumption of the material (Wh / kg) is defined as the product of the specific capacity (Ah / kg) by the average value of the potential (V).

The implementation of the invention

The electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ) with a KTP structure is synthesized by a two-stage ceramic method.

At the first stage, Mi_ _x M ' _x O _y P0 ₄ phosphate is synthesized, which can be obtained using the freeze-drying method or traditional ceramic synthesis. When using the freeze-drying method, monosubstituted or disubstituted ammonium phosphate (NH ₄ H ₂ P0 ₄ or (NH ₄ ) ₂ HP0 ₄ ) and the corresponding salts of the transition metal M and metal M 'are dissolved in distilled H ₂ 0 with constant stirring at 5СН-100 ° C, with the addition of a carbon source and a reducing agent. The resulting solution is sprayed into liquid nitrogen and sublimated at a pressure of no higher than 10 ^" atm for 48 ^ -72 hours. The obtained cryogranulate is annealed at 70 (Н900 ° С for 3 ^ 10 hours, controlling the partial pressure of oxygen in the system depending on on the oxidation state of the transition metal used in the electrode material.

Preferably used salts of the transition metal M and metal M 'are presented in table 1.

Table 1.

Examples of compounds used to prepare intermediates of the formula Mi_ _x M ' _x O _y P0 ₄ by freeze-drying.

As a reducing agent, ascorbic acid, citric acid, acetic acid, glucose, and sucrose can be used.

When Mi_ _x M ' _x O _y P0 _{4 is} obtained by ceramic synthesis, ammonium phosphate (NH ₄ H ₂ P0 ₄ or (NH ₄ ) ₂ HP0 ₄ ), reagents containing M and M', as well as a carbon source (at this stage, as the carbon source can be various forms of carbon, including soot, graphite, carbon nanotubes, graphene, or organic compounds such as ascorbic acid, citric acid, acetic acid, glucose, sucrose) are thoroughly ground and homogenized in a ball mill, and then annealed at 700 ^ -950 ° С for 10-20 hours, maintaining a constant partial pressure ie oxygen in the system.

As reagents containing M and M ', you can use the compounds shown in table 2. Table 2.

Examples of compounds used to obtain compounds of the formula Mi_ _x M ' _x O _y P0 ₄ ceramic method.

In the second stage, the resulting Mi_ _x M ' _x O _y P0 _{4 is} mixed with AF, AHF ₂ , A ₂ C0 ₃ or a mixture of NH ₄ F and A ₂ C0 ₃ and annealed in a stream of argon (or nitrogen) at 550-n575 ° С within 30 minutes, followed by hardening to room temperature. The amount of residual soot in phosphate Mi_ _x M ' _x O _y P0 ₄ is determined chemically or by thermogravimetric methods.

The result is an electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ), crystallizing in rhombic syngony.

To prepare the composite material, 60-99% of the mass of the obtained electrode material is thoroughly mixed with one or more electrically conductive additives and one or more binders. The content of electrically conductive additives in the composition of the composite material can vary from 0.5% to 20% of the mass, the binder can also vary from 0.5% to 20% of the mass. The mixture is uniformly applied to an aluminum or copper substrate (current collector), pre-dried and rolled on rollers. Then cut out electrodes with a diameter of 16 mm, weighed and finally dried under reduced pressure (10 ^" atm) at 1 10 ° C for 4 hours to remove residual water and solvent [Thorat IV, Mathur V., Harb JN, Wheeler DR (2006) , Journal of Power Sources, 162, 673-678].

The thickness of the layer of active material (each layer of active material on one of the surfaces of each current collector) is usually approximately in the range of 1-500 microns, preferably 2-100 microns, taking into account the purpose of the battery and the value of ionic conductivity.

Various forms of carbon can be used as an electrically conductive additive, in particular graphite, carbon black, carbon nanotubes, fullerene, conductive polymeric materials based on polyaniline, polypyrrole, polyethylene dioxithiophene or mixtures thereof. However, the electrically conductive additive is not limited to the listed examples. Well-known materials that are currently used as electrically conductive additives for a lithium-ion battery may be used. These electrically conductive additives may be used alone, or two or more of them may be used in combination.

As a binder, polyvinylidene fluoride in N-methylpyrrolidone (pVdF) and its modifications (for example, Solef ^® 6010, Solef ^® 6020, Solef ^® 5130, Solef ^® 21216), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) can be used. , polyacrylonitrile (PAN), polyimide (PI), polyamide (PA), carboxymethyl cellulose (CMC), or a suspension of perfluoroethylene in water. Fluoroplast or Teflon is preferably used as perfluoropolyethylene.

Based on the obtained electrodes, electrochemical cells with a non-aqueous electrolyte, a separator and a counter electrode are collected, then electrochemical tests are carried out. As an electrolyte, it is preferable to use a solution of LiPF ₆ salt, or LiBF ₄ in a mixture of alkyl carbonates or sulfones with a salt concentration of 0.5 to 2 mol / L. As alkyl carbonates, a mixture of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), the volume ratio of which can vary, is used. As sulfones, it is preferable to use ethyl methyl sulfone, tetramethylene sulfone. Borosilicate glass, fluoroplastic, polyamide, commercial membranes made of polyethylene or polypropylene or polyethylene terephthalate with or without ceramic are used as a separator.

The invention is illustrated by examples confirming the practical implementation of the invention. The following examples are illustrative in relation to the proposed technical solution and illustrate the problems solved by this invention, however, these examples should not be construed as limiting. Specialist in this field, based on the information given in the description, can get the electrode material of the formula KTP, the specified method.

Example 1

The electrode material KVP0 ₄ F was synthesized by a two-stage ceramic method.

In the first stage, VP0 ₄ phosphate was obtained by freeze-drying. For this, the starting reagents 1.75 g of NH ₄ V0 ₃ and 1.68 g of NH ₄ H ₂ P0 _{4 were} dissolved in 250 ml of distilled Н ₂ 0 with constant stirring at 80 ° С, with the addition of 1.70 g ascorbic acid. The resulting solution was sprayed into liquid nitrogen and subjected to sublimation at a pressure of 10 atm. within 72 hours. The obtained cryogranulate was annealed at 850 ° C for 5 hours.

In the second stage, the obtained 2.15 g of VP0 _{4 was} mixed with 1.16 g of KHF ₂ in a 1: 1 molar ratio (the amount of residual carbon black in VP0 ₄ phosphate was determined chemically or by thermogravimetric methods) and annealed in an argon stream at 600 ° C for 90 minutes, followed by quenching to room temperature.

The resulting material is vanadium potassium fluoride phosphate crystallizing in rhombic syngony with unit cell parameters a = 12.8201 (3) A, b = 6.3957 (2) A, c = 10.6118 (2) A *.

* - unit cell parameters can vary within the value of three standard deviations.

Example 2

The electrode material KVP0 ₄ F was synthesized according to the scheme described in example 1, only V ₂ Os and (NH ₄ ) ₂ HP0 _{4 were} used as starting components.

Example 3

The electrode material KVP0 ₄ F was synthesized according to the scheme described in example 1, except that in the second stage 0.55 g of NH ₄ F and 1.01 g of K ₂ C0 ₃ were added to 2.15 g of the obtained VP0 ₄ , thoroughly ground and homogenized, and then annealed in a stream of argon at 600 ° C for 90 minutes, followed by quenching to room temperature.

Example 4

At the first stage, vanadium phosphate VP0 _{4 was} obtained by the ceramic method. For this, 1.75 g of NH ₄ V0 ₃ , 1.68 g of NH ₄ H ₂ P0 _4, and 0.10 g of carbon black were thoroughly ground and homogenized in a ball mill, and then annealed at 850 ° С in an argon flow for 15 hours.

In the second stage, 2.15 g of the obtained VP0 _{4 were} mixed with 1.16 g of KHF ₂ in a 1: 1 molar ratio and annealed in an argon stream at 600 ° C for 90 minutes, followed by quenching to room temperature.

Example 5 The electrode material KVP0 ₄ F was synthesized according to the scheme described in example 4, only V ₂ O ₅ and (NH ₄ ) ₂ HP0 _{4 were} used as starting components _. Example 6.

The electrode material KVP0 ₄ F was synthesized according to the scheme described in example 4, except that in the second stage 0.55 g of NH ₄ F and 1.01 g of K ₂ COz were added to 2.15 g of the obtained VP0 ₄ , carefully triturated and homogenized, and then annealed in a stream of argon at 600 ° C for 90 minutes, followed by quenching to room temperature.

Example 7

The electrode material KV _0. 9AI _0.1 PC F was synthesized by the two-stage ceramic method. At the first stage, phosphate V _0. 9AI _0.1 PC was obtained by freeze-drying. For this, 1.57 g of NH ₄ V0 ₃ and 1.67 g of NH ₄ H ₂ P0 _{4 were} dissolved in 250 ml of distilled Н ₂ 0 with constant stirring at 80 ° С, with the addition of 1.70 g of ascorbic acid. Thereto was added 0.56 g Α1 (Ν0 ₃₎ ₃ · 9Η ₂ 0. The resulting solution was sprayed into liquid nitrogen and subjected to sublimation under a pressure of 10 ^"atm. For 72 hours. The resulting kriogranulyat annealed at 850 ° C for 5 hours.

In the second stage, 2.01 g of the obtained V _0. 9AI _0.1 PC was mixed with 1.09 g of KHF ₂ (the amount of residual carbon black in VP0 ₄ phosphate was determined by thermogravimetry) and annealed in an argon stream at 600 ° C for 90 minutes, followed by quenching to room temperature .

Example 8

The electrode material KV _0. 9AI _0.1 PC F was synthesized according to the scheme described in example 7, only V ₂ O ₅ and (NH ₄ ) ₂ HP0 _{4 were} used as starting components _. Example 9.

Electrode material RbVP0 ₄ F was synthesized in a two step method of the ceramic circuit to that described in Example 6, but instead of K ₂ C0 ₃ was used Rb ₂ C0 _3.

Example 10

The electrode material KVo _.7 sCro _.25 P0 ₄ F was synthesized by a two-stage ceramic method.

In the first stage, Vo _.75 Cro _.2 sP0 ₄ phosphate was obtained by freeze-drying. For this, 1.31 g of NH ₄ V0 ₃ and 1.68 g of NH ₄ H ₂ P0 _{4 were} dissolved in 250 ml of distilled H ₂ 0 with constant stirring at 80 ° C, with the addition of 1.70 g of ascorbic acid. 1.50 g of Cr (N0 ₃ ) ₃ -9H ₂ 0 was added to the resulting solution. The resulting solution was sprayed into liquid nitrogen and sublimated at a pressure of 10 atm. within 72 hours. The obtained cryogranulate was annealed in a stream of argon (or nitrogen) at 850 ° C for 5 hours.

In a second step, 2.10 g of obtained Vo _.75 Cro. ₂ sP0 _{4 was} mixed with 1.10 g of KHF ₂ (the amount of residual carbon black in Vo _.7 sCro. ₂ 5P0 ₄ phosphate was determined by thermogravimetry) and annealed in an argon stream at 600 ° С for 90 minutes, followed by quenching to room temperature. Example 11

Electrode material KVP0 ₄ Fo.sOo.5 ceramic synthesized in a two step method.

At the first stage, VOo phosphate was obtained by freeze-drying _. sP0 ₄ .

For this, 1.75 g of NH ₄ V0 ₃ and 1.68 g of NH ₄ H ₂ P0 _{4 were} dissolved in 250 ml of distilled H ₂ 0 with constant stirring at 80 ° C, with the addition of 1.00 g of ascorbic acid.

The resulting solution was sprayed into liquid nitrogen and sublimated at low pressure for 72 hours. The obtained cryogranulate was annealed at 700 ° C for 10 hours in a stream of argon or nitrogen.

In the second stage, 2.20 g of the obtained VOo.sP0 _{4 was} mixed with 1.11 g of KHF ₂ in a 1: 1 molar ratio (the amount of residual soot in VOo phosphate _. SP0 _{4 was} determined by thermogravimetry) and annealed in an argon stream at 600 ° С for 90 minutes followed by hardening to room temperature.

Example 12

The electrode material KTiP0 ₄ F was synthesized by a two-stage ceramic method.

At the first stage, TiP0 ₄ phosphate was obtained by the ceramic method. For this, 1.20 g of TiO ₂ and 1.68 g of NH ₄ H ₂ P0 _{4 were} carefully ground and homogenized in a ball mill, and then annealed at 950 ° С in a stream of argon and hydrogen for 20 hours.

In the second stage, 2.12 g of the obtained TiP0 _{4 was} mixed with 1.10 g of KHF ₂ and annealed in an argon stream at 700 ° C for 90 minutes, followed by quenching to room temperature.

Example 13 The electrode material KTiP0 ₄ F was synthesized according to the scheme described in example 12, except that in the second stage, 0.55 g of NH ₄ F and 1.01 g of K ₂ CO ₃ were added to 2.12 g of the obtained TiP0 ₄ , carefully triturated and homogenized, and then annealed in a stream of argon at 700 ° C for 90 minutes, followed by quenching to room temperature.

Example 14

A composite material based on an electrode material of composition KVP0 ₄ F was obtained by thoroughly mixing 70% of the mass, the active material KVP0 ₄ F, 15% carbon black (Carbon Super-C) used as an electrically conductive additive, and 15% polyvinylidene fluoride used as a binder. Galvanostatic and potentiostatic measurements were carried out in two-electrode clamping cells with a lithium anode. A solution of LiPF ₆ in a mixture of alkyl carbonates (EC ethylene carbonate, DMC dimethyl carbonate, PC propylene carbonate) was used as an electrolyte, borosilicate fiberglass, polymer membranes were used as a separator. Example 15

The electrode material LiVP0 ₄ F was obtained by electrochemical substitution of K for Li. The initial KVP0 ₄ F electrodes were charged in an electrochemical cell with a Li anode up to 4.8 V rel. Li / Li ⁺ at a speed of C / 20, kept at this potential for 5 hours to remove K ⁺ ions and washed with dimethyl carbonate. Based on the obtained electrodes, model two-electrode cells were assembled, which were cycled in the potential range 2.0 ^ -4.7 V rel. Li / Li ⁺ and discharged to a potential of 2.0 V.

Example 16

The electrode material LiVP0 ₄ F was obtained by ion exchange of K for Li. For this, the starting material KVP0 ₄ F was kept in a solution of LiBr (or L1NO ₃ ) in absolute ethanol (or acetonitrile) with constant stirring and a temperature of 60 ° C for 48 hours.

Example 17

The electrodes were prepared by thoroughly mixing 80% of the mass, KVP0 ₄ F active material, 10% of the mass, Carbon Super-C carbon black and 10% of a binder, which was used as polyvinylidene difluoride dissolved in метил-methylpyrrolidone. The mixture was uniformly applied to an aluminum substrate (current collector), previously dried and rolled on rollers. Then, electrodes were cut to 16 mm diameter, weighed and finally dried at 10 ^"atm at 110 ° C for 4 hours to remove residual water and solvent. Example 18

Based on the electrodes (example 17), electrochemical cells were assembled in an inert box (M-Braun), in which 1M LiPF ₆ solution in an EC: DMC mixture (1: 1 by volume) and borosilicate glass were used as an electrolyte as a separator.

Example 19

A series of electrodes was prepared by thoroughly mixing X% mass, KVP0 ₄ F active material, Y% mass, Carbon Super-C carbon black and Z% binder, which was used as a commercial Solef ^® 5130 binder dissolved in метил-methylpyrrolidone. The values of X, Υ, Z are shown in table 3. The mixture was uniformly applied to the substrate (current collector), pre-dried and rolled on rollers. Then, electrodes were cut to 16 mm diameter, weighed and finally dried at 10 ^"atm at 110 ° C for 4 hours to remove residual water and solvent. On the basis of gathered in an inert electrode box (M- Braun) electrochemical cell, in which as The electrolyte used a 1M solution of LiPF ₆ in a mixture of EC: DMC (1: 1 by volume) and borosilicate glass as a separator.

Table 3

Claims

CLAIM

1. The electrode material for metal-ion batteries of the general formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ), characterized by a crystalline structure of the type "potassium titanyl phosphate", where A is an alkali metal, M is a transition metal , M 'is the metal used as a modifying additive, where 0 <x <0.3, 0 <y <1.

2. The electrode material according to claim 1, characterized in that the alkali metal is Li and / or Na, and / or K, and / or Rb.

3. The electrode material according to claim 1, characterized in that the transition metal M is Ti, V, Nb, Cr, Mo, Mn, Fe, or a mixture thereof.

4. The electrode material according to claim 1, characterized in that Mg, Zn, Al, Ga or a mixture thereof is used as a modifying additive M '.

5. A method of producing an electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ), where K and / or Rb acts as an alkali metal (A), including the production of phosphate Mi_ _x M' _x O _y P0 ₄ by freeze drying, followed by annealing or ceramic synthesis, followed by mixing the obtained phosphate with AF, AHF ₂ , A ₂ C0 ₃ or a mixture of HF and A ₂ C0 ₃ and annealing the resulting mixture.

6. A method of obtaining an electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ), where Li and / or Na acts as an alkali metal (A), or a mixture with K and / or Rb, including obtaining electrode material of the formula A (Mi_ _x M ' _x ) P0 ₄ (Fi_ _y O _y ), where K and / or Rb acts as an alkali metal (A) according to claim 5, followed by complete or partial replacement of K and / or Rb by Li, Na.

7. The method according to claim 6, characterized in that the substitution of K and / or Rb for Li and / or Na is carried out using ion exchange or electrochemical substitution.

8. A composite material for the manufacture of electrodes for metal-ion batteries, including 60 - 99% of the mass, compounds according to claim 1, one or more electrically conductive additives and one or more organic binder components.

9. The composite material according to claim 7, characterized in that graphite, graphene, carbon black, carbon nanotubes, conductive polymeric materials based on polyaniline, polypyrrole, polyethylene dioxithiophene or a mixture thereof in an amount of from 0.5 to 20% by mass are used as an electrically conductive additive .

10. The composite material according to claim 7, characterized in that the polyvinylidene fluoride dissolved in N-methylpyrrolidone or its derivatives or styrene-butadiene rubbers or a mixture thereof or suspensions of perfluoropolyethylene (fluoroplast, teflon) in water in an amount of from 0.5 to 20% of the mass.

11. The composite material according to claim 8, characterized in that fluoroplastic or teflon is used as perfluoropolyethylene.

12. An electrode for metal-ion batteries, comprising a composite material according to claim 8, placed on a metal substrate.

13. A metal-ion battery comprising a cathode, anode, and an electrolyte, wherein one of the electrodes is made according to claim 12.