WO2023082410A1 - Selenide glass material, preparation method therefor, and use thereof - Google Patents

Abstract

A selenide glass material, a preparation method therefor, and a use thereof. The selenide glass material comprises an active substance glass powder, the raw materials of the glass powder comprising a network product of selenide MSe_x, a transition metal oxide DO_y, and a network exosome oxide AO_n at a mass ratio of (10-50):(30-80):(10-40); M in MSe_x is one or more selected among Ti, Si, Sn, Pb, P, As, Sb, Bi, O, S and Te; D in DO_y is one or more selected among Fe, V, Zr, Sb, Mo, Cr, Nb, Ta, Ni, Co, Cu and Mn; and A in AO_n is one or more selected among Li, Na, K, Rb, Cs, Ca, Sr, Ba, Y, In, La, Zr, Th, Be, Mg, Zn, Al and Ga. The described selenide glass material has the advantages of large specific capacity, high voltage, low loss rate in the first cycle, and so on.

Description

A kind of selenide glass material and its preparation method and application

This application claims the priority of the Chinese patent application with the application number 202111369439.8 and the invention title "a selenide glass material and its preparation method and application" submitted to the China Patent Office on November 15, 2021, the entire content of which is incorporated by reference incorporated in this application.

technical field

The invention belongs to the technical field of glass materials, in particular to a selenide glass material and its preparation method and application.

Background technique

Lithium-ion battery is a new generation of green high-energy battery with excellent performance, and has become one of the focuses of high-tech development. Lithium-ion batteries have the following characteristics: high voltage, high capacity, low consumption, no memory effect, no pollution, small size, small internal resistance, less self-discharge, and more cycles. Because of the above-mentioned characteristics, lithium-ion batteries have been applied to many civilian and military fields such as mobile phones, notebook computers, video cameras, and digital cameras.

The main constituent materials of lithium-ion batteries include electrolyte, separator materials, positive and negative electrode materials, etc. Among them, the anode materials of lithium-ion batteries are mainly cobalt, manganese, nickel, etc. and their composite oxides. Commercial applications have demonstrated that these materials have high potential and stability, but their specific capacity is low (205 mAh/g). For example, as the earliest commercial positive electrode material, the theoretical specific capacity of lithium cobaltate (LiCoO ₂ ) is 273mAh/g, but the actual specific capacity is only about 140mAh/g, and there are also defects of high price and high toxicity; although lithium nickelate The specific capacity of (LiNiO ₂ ) can reach 150mAh/ _g , slightly higher than that of LiCoO ₂ , but in the synthesis process of LiNiO ₂ , the loss of lithium is easy to occur, and it is difficult to synthesize LiNiO ₂ that meets the standard chemical composition; Compared with lithium manganese oxide (LiMnO ₄ ), the price is low, but the theoretical specific capacity is low (148mAh/g), and the cycle performance is poor; the theoretical specific capacity of lithium iron phosphate (LiFeO ₄ ) can reach 170mAh/g, but the conductivity Poor, low energy density. The theoretical specific capacity of negative electrode graphite is 372mAh/g, and the actual specific capacity is 360mAh/g. It can be seen that the positive electrode material limits the specific capacity of lithium-ion batteries. These factors restrict the improvement of the performance of lithium-ion batteries, and there is an urgent need to research and develop new high-performance cathode materials to meet the application of energy storage devices. The search space for high-energy-density cathode materials expands to cation-disordered lithium transition metal oxides.

Semiconductor oxide glass is considered to be a lithium-ion battery electrode material with great potential application prospects. Existing patents have disclosed that composite vanadium-phosphorus glass is used for positive electrode materials of lithium ion batteries, such as V ₂ O ₅ -Li ₃ PO ₄ -CaC ₂ (CN111484247A), V ₂ O ₅ -LiBO ₂ -graphene (CN111668468A), such The lithium-ion battery assembled with positive electrode materials has high specific capacity and strong battery cycle stability, which can improve the electron and ion transmission rate and inhibit the volume expansion in the charging and discharging process. However, there are problems such as small specific capacity, large internal resistance, low voltage, and large loss rate in the first cycle.

Contents of the invention

In view of this, the object of the present invention is to provide a kind of selenide glass material and its preparation method and application, this glass material is used as the positive electrode of lithium-ion battery, makes battery have the advantages of large specific capacity, high voltage, and first cycle loss rate .

The invention provides a selenide glass material, which includes active material glass powder, and the preparation raw material of the active material glass powder includes a network with a mass ratio of (10-50):(30-80):(10-40) Selenide MSe _x , transition metal oxide DO _y and network exosome oxide AO _n ;

said x, y, and n balance the valence;

In the MSe _x, M is selected from one or more of Ti, Si, Sn, Pb, P, As, Sb, Bi, O, S, Te;

D in DO _y is selected from one or more of Fe, V, Zr, Sb, Mo, Cr, Nb, Ta, Ni, Co, Cu and Mn;

A in the network exosome oxide AO _n is selected from Li, Na, K, Rb, Cs, Ca, Sr, Ba, Y, In, La, Zr, Th, Be, Mg, Zn, Al and Ga. one or more.

In the present invention, _x in the network generator selenide MSex is selected from 1, 2 or 3; the network generator selenide _MSex is preferably selected from SiSe ₂ , SnSe, P ₂ Se ₅ , SeO ₂ , TeSe ₂ one or more of .

In the present invention, the transition metal oxide DO _y is selected from one of Fe ₂ O ₃ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , NiO, Co ₂ O ₃ and Mn ₂ O ₇ or more.

In the present invention, the exosome oxide AOn _is selected from Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O, CaO, SrO, BaO, Y ₂ O ₃ , In ₂ O _3. La ₂ O, ZrO ₂ , ThO ₂ , BeO, MgO, ZnO, Al _{2 O 3 , Ga 2 O 3 ,} SnO, PbO, SnO ₂ , Te ₂ O ₅ , Te ₂ O ₃ and Sb ₂ O ₃ one or more of .

In the present invention, the selenide glass material also includes a binder and a conductive filler;

The mass ratio of the active material glass powder, binder and conductive filler is (6～10):(2～3):(1～2), preferably (6～8):(2～3):( 1～2); In a specific embodiment, the mass ratio of the active material glass powder, binder and conductive filler is 7:2:1. In the present invention, the binder is preferably polyvinylidene fluoride; the conductive filler is preferably conductive carbon black.

In the present invention, the particle size of the active material glass powder is less than or equal to 400 mesh.

In the present invention, the selenide glass material is the active material of the positive electrode material; the molecular arrangement of the glass is irregular, and its molecules have statistical uniformity in space. In an ideal state, the physical and chemical properties of homogeneous glass (such as refractive index, hardness, elastic modulus, thermal expansion coefficient, thermal conductivity, electrical conductivity, etc.) are the same in all directions. Glassy substances are generally obtained by rapid cooling of melts. When transitioning from a molten state to a glassy state, the viscosity increases sharply during the cooling process, and the particles are too late to be arranged in a regular manner to form crystals, and the latent heat of crystallization is not released. Therefore, the glassy state Substances have higher internal energy than crystalline substances, and their energy is between the molten state and the crystalline state, which belongs to the metastable state. From a mechanical point of view, glass is an unstable high-energy state. For example, there is a tendency to transform into a low-energy state, that is, there is a tendency to devitrify. Therefore, glass is a metastable solid material. Moreover, the process of the glassy substance from the molten state to the solid state is gradual, and the change of its physical and chemical properties is also continuous and gradual. This is obviously different from the crystallization process of the melt. A new phase will inevitably appear during the crystallization process, and many properties will change suddenly near the crystallization temperature point. The glassy substance is completed in a wide temperature range from the molten state to the solid state. As the temperature gradually decreases, the viscosity of the glass melt gradually increases, and finally forms a solid glass, but no new phase is formed during the process. On the contrary, the process of glass heating into melt is also gradual.

The main raw materials for glass production are glass formers, glass regulators and glass intermediates, and the rest are auxiliary raw materials. Among them, the main raw materials refer to oxides introduced into the glass to form a network, intermediate oxides and oxides outside the network; auxiliary raw materials include clarifiers, fluxes, opacifiers, colorants, decolorizers, oxidants and reducers.

In the present invention, the mass ratio of the network product selenide _MSex , transition metal oxide DO _y and network exosome oxide AO _n is (10-50):(30-80):(10-40) , preferably (15-40): (40-70): (10-20); in a specific embodiment, the network product selenide _MSex , transition metal oxide DO _y and network exosome oxide AO _n The mass ratio is 20:60:20, or 15:65:20, or 20:65:15, or 25:60:15, or 40:50:10.

The present invention provides a kind of preparation method of the selenide glass material described in the technical scheme, comprising the following steps:

Mix the network product selenide _MSex , transition metal oxide DO _y and network exosome oxide AO _n , in a protective atmosphere, heat up to 500°C-800°C, keep it warm for 100-300min, and then continue to heat up to 1000°C- 2000°C, keep warm for 10-30 minutes, cool and form, anneal and grind to obtain selenide glass material.

The protective atmosphere is preferably argon.

In the present invention, the annealing temperature is 200-300° C., and the annealing time is 200-2000 min.

In the present invention, the temperature is preferably raised to 500°C-800°C at a rate of 5-15°C/min. In the present invention, it is preferred to heat up to 500-800°C at a rate of 5-15°C/min, more preferably to 500-800°C at a rate of 5-10°C/min; in the present invention, it is preferred to heat up to 600°C ~800°C, more preferably 650°C-750°C for heat preservation; in the embodiment provided by the present invention, specifically heat up to 700°C for heat preservation; the heat preservation time is preferably 100-200min.

The present invention preferably continues to heat up to 1000°C to 2000°C at a rate of 5 to 15°C/min, preferably to 1000°C to 1500°C for heat preservation; the heat preservation time is 10 to 30 minutes, preferably 10 to 20 minutes; In the present invention, the temperature is preferably raised to 1000-2000°C at a rate of 5-15°C/min, more preferably 1000-2000°C at a rate of 10-15°C/min.

After heat preservation, cooling and forming; in the present invention, it is preferred to cool and form on the surface of liquid tin; the glass liquid is spread on the surface of the tin liquid, flattened, forming smooth upper and lower surfaces, hardened, and then introduced into the transition roller table after cooling.

Finally, the glass is obtained by annealing treatment; the temperature of the annealing treatment is preferably 200°C-300°C; the time of the annealing treatment is preferably 200-2000min, more preferably 200-1000min, and more preferably 200-500min; provided in the present invention In an embodiment, the time for the annealing treatment is specifically 300 minutes.

The glass is ground to obtain active material glass powder; the grinding is preferably performed by using a ball mill; the particle size of the active material glass powder is preferably less than or equal to 400 mesh.

If the selenide glass material also includes binder and conductive filler, after grinding to obtain the active material glass powder, continue to mix with binder, conductive filler and solvent, ball mill, and coat on the current collector to obtain the selenide glass material , that is, the positive electrode material.

The active material glass powder, binder, conductive filler and solvent are mixed and ball-milled, and then coated on the current collector; the mass ratio of the active material glass powder, binder and conductive filler is preferably (6-10) : (2～3): (1～2), more preferably (6～8): (2～3): (1～2); In the embodiment provided by the present invention, the active material glass powder, The mass ratio of binder to conductive filler is specifically 7:2:1; the binder is preferably polyvinylidene fluoride; the particle size of the conductive filler is preferably 1-10 μm; the conductive filler is preferably conductive carbon black. The solvent is preferably N-methylpyrrolidone; the current collector is preferably aluminum foil; the thickness of the coating is 60-120 μm.

After coating, it is dried to obtain a glass positive electrode material.

The preparation method provided by the invention is simple and easy to implement, and is beneficial to popularization and application.

The present invention provides a lithium ion battery, comprising a positive electrode material; the positive electrode material is the selenide glass material described in the above technical solution or the selenide glass material prepared by the preparation method described in the above technical solution.

The invention provides a selenide glass material, which includes active material glass powder, and the preparation raw material of the active material glass powder includes a network with a mass ratio of (10-50):(30-80):(10-40) Selenide _MSex , transition metal oxide DO _y and network exosome oxide AO _n ; said x, y and n make the valence balance; M in said _MSex is selected from Ti, Si, Sn, Pb, P, One or more of As, Sb, Bi, O, S, Te; D in DO _y is selected from Fe, V, Zr, Sb, Mo, Cr, Nb, Ta, Ni, Co, Cu and Mn One or more of them; A in the network exosome oxide _AOn is selected from Li, Na, K, Rb, Cs, Ca, Sr, Ba, Y, In, La, Zr, Th, Be, Mg , one or more of Zn, Al and Ga. The open-circuit voltage of the lithium-ion battery assembled with the above-mentioned composition of selenide glass material as the positive electrode is 3.9-4.4; the initial capacity is 263-310mAh/g; the first cycle coulombic efficiency is 91%-96%; the discharge capacity of the battery after 100 cycles is 250-294mAh /g, the cycle efficiency is 92.3% to 97.4%. The provided glass positive electrode material has problems such as large specific capacity, high voltage, and small first-cycle loss rate, and the preparation method of the present invention has simple process, is easy to implement, and is beneficial to popularization and application.

Description of drawings

Fig. 1 is the XRD spectrogram of the glass powder that the embodiment of the present invention 3 prepares;

Fig. 2 is the SEM scanning electron micrograph of the glass powder prepared in Example 5 of the present invention.

Detailed ways

In order to further illustrate the present invention, a selenide glass material provided by the present invention and its preparation method and application are described in detail below in conjunction with examples, but they should not be understood as limiting the protection scope of the present invention.

Example 1

In parts by weight, 20 parts of SiSe ₂ , 60 parts of Fe ₂ O ₃ , and 20 parts of Li ₂ O were mixed, stirred and ground evenly, and the obtained mixed raw materials were transferred to an alumina crucible. Melt in a tubular heating furnace under argon protection, raise the temperature to 700°C at a heating rate of 5°C/min, and hold for 100 minutes; then raise the temperature to 1000°C at a heating rate of 15°C/min, and hold for 30 minutes; quickly mix the mixture The liquid is poured over the surface of the liquid tin to shape the glass. The molten glass is spread on the surface of the tin liquid, flattened to form a flat upper and lower surface, hardened, cooled, and then led to the transition roller table. The rollers of the roller table rotate, and the glass ribbon is pulled out of the tin tank and enters the annealing furnace. The temperature of the furnace body is 200°C, and the glass is obtained after annealing for 300 minutes.

Crush the glass, grind it sufficiently with a ball mill, and sieve (400 mesh) to obtain glass powder.

Mix glass powder, binder (polyvinylidene fluoride), and conductive carbon black (particle size distribution 1-10 μm) powder with a mass ratio of 7:2:1, and then drop an appropriate amount of solvent N-methylpyrrolidone (accounting for Powder 20%) ball milling, the slurry of gained is coated on aluminum foil and dries, and the thickness of coating is 120 μ m, then with this aluminum foil as positive electrode, 1mol/L LiPF ₆ is ethylene carbonate/dimethyl carbonate (volume ratio 1: 1) Electrolyte, Celgard 2025 is the diaphragm, and the lithium sheet is the counter electrode, which is assembled into a CR2025 coin battery in a glove box. The charging and discharging performance of the comparative lithium-ion battery under different current densities in the voltage range of 2.0-4.2V was tested on the electrochemical workstation.

Embodiment 2-5

According to the process flow of Example 1, the types and addition amounts of different network products such as selenide _MSex , _VOy transition metal oxides, and AO _n network exosome oxides are shown in Table 1.

Table 1 The types and amounts of raw materials used in the preparation of glass cathode materials in Examples 1 to 5

Example	MS x	number of copies	VO	number of copies	AO	number of copies
1	SeO 2	15	Fe2O3 _	65	Li 2 O	20
2	TeSe 2	20	V 2 O 5	60	K 2 O	20
3	P 2 Se 5	40	Nb 2 O 5	50	Te 2 O 5	10
4	Sete	25	Co 2 O 3	60	Al 2 O 3	15
5	SiSe2	20	Mn 2 O 7	65	Te 2 O 5	15

Comparative example 1

The dry V ₂ O ₅ powder and P ₂ O ₅ powder were mixed in a stoichiometric ratio and melted in a hydrogen atmosphere to prepare a 80V ₂ O ₅ ·20P ₂ O ₅ glass sample. The mixture was placed into a quartz crucible after stirring and uniform mixing. Glass melting is carried out in a tube furnace. Heating at 800° C. for 5 minutes to obtain a vanadium-phosphorus glass sample melt. The molten glass was poured on an iron plate, then annealed in a muffle furnace at 250 °C for 2 h, and then cooled with the furnace. Grind the prefabricated glass into powder with an agate mortar and pestle, with a particle size of <20 μm.

The electrode is made by mixing active material (vanadium phosphorus glass powder), carbon black and polytetrafluoroethylene (PTFE) binder in a mass ratio of 8:1.5:0.5. The weighed vanadium phosphorus glass powder and carbon black were put into an agate mortar and ground for 30 minutes to obtain a uniform mixture. Then, polytetrafluoroethylene was added to the prepared mixture and vigorously mixed to obtain a uniform film (thickness 80 μm). The prepared cathode film was punched into a disc with a circular cutter with a diameter of 8 mm, and then evenly pasted on the aluminum grid. Then, CR2032 coin cell (316L stainless steel, polypropylene gasket) was used as cathode, 1mol/L LiPF ₆ was ethylene carbonate/dimethyl carbonate (volume ratio 1:1) electrolyte, Celgard 2025 was diaphragm, lithium sheet As a counter electrode, a CR2032 type coin cell was assembled in a glove box. The charging and discharging performance of the comparative lithium-ion battery under different current densities within the voltage range of 2.0-4.2V was tested on the electrochemical workstation. The test data showed a specific capacity of 270mAh g ^-1 for the first time, and a capacity retention of about 90% after 100 cycles. Furthermore, after 300 cycles, a specific capacity of 220 mAh ^g is delivered at a high current density of 85 mA ^g , which corresponds to a capacity retention of 80%.

See Table 2 for the performance test results of the lithium-ion batteries assembled with the glass cathode materials prepared in Examples 1-5 and Comparative Example 1.

Table 2 Performance test results of batteries assembled with glass positive electrodes prepared in Examples 1-5 of the present invention and Comparative Example 1

As can be seen from the above examples, the present invention provides a kind of selenide glass material, including active material glass powder, and the preparation raw material of described active material glass powder comprises mass ratio is (10～50):(30～80):(10 ~40) network product selenide _MSex , transition metal oxide DO _y and network exosome oxide AO _n ; said x, y and n balance the valence; M in said _MSex is selected from Ti, Si, One or more of Sn, Pb, P, As, Sb, Bi, O, S, Te; D in the DO _y is selected from Fe, V, Zr, Sb, Mo, Cr, Nb, Ta, Ni One or more of , Co, Cu and Mn; A is selected from Li, Na, K, Rb, Cs, Ca, Sr, Ba, Y, In, La, Zr in the network exosome oxide _AOn , Th, Be, Mg, Zn, Al and Ga in one or more. The open-circuit voltage of the lithium-ion battery assembled with the above-mentioned composition of selenide glass material as the positive electrode is 3.9-4.4V; the initial capacity is 263-310mAh/g; the first-cycle Coulombic efficiency is 91%-96%; the discharge capacity of the battery after 100 cycles is 250- 294mAh/g, cycle efficiency 92.3% to 97.4%. The provided glass positive electrode material has problems such as large specific capacity, high voltage, and small first-cycle loss rate, and the preparation method of the present invention has simple process, is easy to implement, and is beneficial to popularization and application.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A selenide glass material, including active material glass powder, the active material glass powder includes network product selenide _MSex , transition metal oxide DO _y and network exosome oxide AO _n ;

   said x, y, and n balance the valence;

   In the MSe _x, M is selected from one or more of Ti, Si, Sn, Pb, P, As, Sb, Bi, O, S, Te;

   D in DO _y is selected from one or more of Fe, V, Zr, Sb, Mo, Cr, Nb, Ta, Ni, Co, Cu and Mn;

   A in the network exosome oxide AO _n is selected from Li, Na, K, Rb, Cs, Ca, Sr, Ba, Y, In, La, Zr, Th, Be, Mg, Zn, Al and Ga. one or more.
2. The selenide glass material according to claim 1, characterized in that the network-forming selenide _MSex is selected from one or more of SiSe ₂ , SnSe, P ₂ Se ₅ , SeO ₂ , and TeSe ₂ .
3. The selenide glass material according to claim 1, wherein the transition metal oxide DO _y is selected from Fe ₂ O ₃ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , NiO, Co ₂ One or more of O ₃ and Mn ₂ O ₇ .
4. The selenide glass material according to claim 1, characterized in that, the outer network oxide _AOn is selected from Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O, CaO, SrO , BaO, Y ₂ O ₃ , In ₂ O ₃ , La ₂ O, ZrO ₂ , ThO ₂ , BeO, MgO, ZnO, Al ₂ O ₃ , Ga ₂ O ₃ , SnO, PbO, SnO ₂ , Te ₂ O ₅ , one or more of Te ₂ O ₃ and Sb ₂ O ₃ .
5. Selenide glass material according to claim 1, is characterized in that, described selenide glass material also comprises binding agent and conductive filler;

   The mass ratio of the active material glass powder, binder and conductive filler is (6-10):(2-3):(1-2).
6. The selenide glass material according to claim 1, characterized in that the particle size of the active material glass powder is less than or equal to 400 mesh.
7. A method for preparing a selenide glass material according to any one of claims 1 to 6, comprising the following steps:

   Mix the network product selenide _MSex , transition metal oxide DO _y and network exosome oxide AO _n , in a protective atmosphere, heat up to 500°C-800°C, keep it warm for 100-300min, and then continue to heat up to 1000°C- 2000°C, keep warm for 10-30 minutes, cool and form, anneal and grind to obtain selenide glass material.
8. The preparation method according to claim 7, characterized in that, the temperature of the annealing is 200-300° C., and the time is 200-2000 min.
9. The preparation method according to claim 7, characterized in that the temperature is raised to 500°C-800°C at a rate of 5-15°C/min;

   Raise the temperature to 1000-2000°C at a rate of 5-15°C/min.
10. A lithium ion battery, characterized in that it includes a positive electrode material;

    The anode material is the selenide glass material according to any one of claims 1-6 or the selenide glass material prepared by the preparation method according to any one of claims 7-9.

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