Argyrodite type solid electrolyte, preparation method thereof and battery

Abstract

The invention provides argyrodite type solid electrolyte, a preparation method thereof and a battery, and relates to the technical field of batteries. The general chemical formula of the argyrodite type solid electrolyte is Li < 5.5 + a + 2bP < 1-a-b > M < 1aM < 2bS < 4.5 > X < 1.5 >, M < 1 > is selected from a group IVA element and / or a group IVB element, M < 2 > is selected from any one or more of a group IIIB element, a group IIIA element and a group VA element, X is halogen, a is more than or equal to 0.1 and less than or equal to 0.3, and b is more than or equal to 0.3 and less than or equal to 0.5. By controlling the doping amount of the element M1 and the element M2 in the argyrodite type solid electrolyte to be within the range, the mutual synergistic effect between the elements can be further improved, so that the ionic conductivity of the argyrodite type solid electrolyte can be further improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a sulfosilver germanium ore type solid electrolyte, its preparation method, and a battery. Background Technology

[0002] Lithium-ion batteries dominate the fields of electric vehicles, consumer electronics, and large-scale energy storage due to their excellent energy density and mature industrial chain. However, traditional liquid lithium-ion batteries use organic electrolyte systems, which pose serious safety hazards such as flammability, leakage, and thermal runaway. The frequent battery fires in recent years have highlighted this technological bottleneck. At the same time, as the energy density requirements of new energy vehicles and energy storage power stations continue to increase, the existing liquid lithium-ion battery system is gradually approaching its theoretical limit, urgently requiring breakthrough technological innovation.

[0003] Against this backdrop, all-solid-state lithium-ion batteries are considered a key development direction for next-generation energy storage technology due to their inherent safety and potential high energy density advantages. As the core component of all-solid-state batteries, the performance of the solid electrolyte directly determines the overall performance of the battery. Among numerous solid electrolyte materials, sulfide-based solid electrolytes stand out due to their extremely high room-temperature ionic conductivity (10⁻⁶ Ω·cm). -3 ~10 -2 With its excellent machinability (good cold-pressing formability) and good interfacial contact characteristics with electrode materials, the [PS4] type sulfide electrolyte is considered one of the most promising technologies for industrialization. Among them, the silver-germanium sulfide electrolyte (typically with the chemical formula Li6PS5X, where X = Cl, Br, I) exhibits excellent lithium-ion conductivity due to its unique crystal structure and tunable ion transport channels. This material has a face-centered cubic crystal structure, composed of [PS4]. 3- The three-dimensional ion transport network constructed by tetrahedrons and halide ions provides a channel for rapid migration of lithium ions. Simultaneously, the partially disordered arrangement within the structure further promotes ion conduction, resulting in a room-temperature ionic conductivity of up to 10. -3 With a conductivity exceeding S / cm, this solid-state electrolyte material system is one of the most promising for industrialization. This material system not only possesses ionic conductivity approaching that of liquid electrolytes but also exhibits excellent mechanical properties and thermal stability, making it considered the most promising candidate material for the commercial application of all-solid-state lithium-ion batteries.

[0004] However, the ionic conductivity of existing silver-germanium sulfide solid electrolytes remains insufficient, especially at room temperature, where it falls short of the requirements for high-power batteries. Currently, the modification of silver-germanium sulfide materials mainly employs ion doping strategies. However, the key mechanisms by which elemental doping affects the ionic conductivity of silver-germanium sulfide materials are not fully understood. In particular, the relationship between local lattice distortion and conductivity lacks systematic research, resulting in a lack of theoretical guidance for material optimization and hindering breakthroughs in conductivity improvement.

[0005] Existing technologies mostly employ constant heating rate or single-temperature sintering mode. This mode is prone to two key problems: First, the precursor reaction is uneven. For example, the reactivity of raw materials such as Li2S and P2S5 varies greatly. Uniform heating may cause some components to melt prematurely and others to react insufficiently, thus generating impurity phases or sulfur vacancy defects. Second, the crystal growth is disordered. Rapid heating can easily cause grain agglomeration, while slow uniform heating may lead to incomplete crystal phase transformation, affecting the core properties of the material such as ionic conductivity. Summary of the Invention

[0006] The main objective of this invention is to provide a sulfosilver germanium ore-type solid electrolyte, its preparation method, and a battery, in order to solve the problem of low ionic conductivity of solid electrolytes in the prior art.

[0007] To achieve the above objectives, according to one aspect of the present invention, a sulforaphane-germanium ore-type solid electrolyte is provided, the general chemical formula of which is Li. 5.5+a+2b P 1-a-b M1 a M2 b S 4.5 X 1.5 M1 is selected from elements of Group IVA and / or Group IVB, M2 is selected from any one or more elements of Group IIIB, Group IIIA and Group VA, X is a halogen, 0.1≤a≤0.3, 0.3≤b≤0.5.

[0008] Furthermore, M1 is selected from Ge and / or Ti; and / or, M2 is selected from any one or more of Sc, Ga, Al, and Sb; and / or, X is selected from any one or more of F, Cl, Br, and I.

[0009] Further, M1 is a combination of Ge element and Ti element, and the molar ratio of Ge element to Ti element is (0.4~0.6):(0.4~0.6); and / or, M2 is a combination of Sb element and Sc element, and the molar ratio of Sb element to Sc element is (0.3~0.5):(0.5~0.7); and / or, X is a combination of Cl element and I element, and the molar ratio of Cl element to I element is (0.4~0.6):(0.9~1.1).

[0010] Further, the lithium ion conductivity of the argyrodite-type solid electrolyte at 25 °C is 4.19×10 -4 ~8.61×10 -3 S·cm -1 .

[0011] According to another aspect of the present invention, a method for preparing the foregoing argyrodite-type solid electrolyte is provided. The preparation method includes: mixing raw materials including a lithium source, a phosphorus source, an M1 source, an M2 source, a sulfur source and an X source according to a ratio, and then successively performing ball milling, tabletting and calcination treatments to obtain the argyrodite-type solid electrolyte.

[0012] Further, the temperature during the heating process of the calcination treatment is T. When T≤200 °C, the heating rate is 0.5~1 °C / min; when 200<T≤350 °C, the heating rate is 3~4 °C / min; when T<350 °C, the heating rate is 1.5~2.5 °C / min.

[0013] Further, the temperature of the calcination treatment is 450~550 °C; and / or, the heat preservation time of the calcination treatment is 8~12 h.

[0014] Further, the rotation speed of the ball milling is 200~500 rpm; and / or, the ball milling time is 5~24 h; and / or, during the ball milling process, the ball milling tank is scraped once every 1~3 h.

[0015] Further, the pressure of the tabletting is 10~30 MPa; and / or, the pressure holding time of the tabletting is 10~30 min.

[0016] According to yet another aspect of the present invention, a battery is provided, and the battery contains the foregoing argyrodite-type solid electrolyte.

[0017] By applying the technical solution of this invention, the doping of elements M1 and M2 effectively increases the cell parameters and lattice volume of the argyrocerium sulfide solid electrolyte, and significantly extends the bond length between lithium ions and anions in the crystal structure. The increased lattice space provides a wider transport channel for lithium ion migration; the increased bond length between lithium ions and the anion backbone directly weakens the Coulomb attraction between them; these structural changes collectively lead to a significant reduction in the activation barrier for lithium ion migration, thereby contributing to improved ionic conductivity of the argyrocerium sulfide solid electrolyte. In particular, by controlling the doping amounts of elements M1 and M2 in the sulfogermanium ore-type solid electrolyte within the aforementioned range, this application helps to further enhance the synergistic effect between elements, thereby further improving the ionic conductivity of the sulfogermanium ore-type solid electrolyte. Applying this sulfogermanium ore-type solid electrolyte to batteries helps to improve the migration rate of ions in the battery, especially meeting the rapid ion transport requirements during high-current charging and discharging, thus improving the high-rate charging and discharging capability of the battery; at the same time, the ion transport resistance is reduced, the internal resistance of the battery is lowered, the Joule heat during charging and discharging is reduced, and the energy efficiency is higher; in addition, it also helps to improve the low-temperature charging and discharging performance of the battery. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 The XRD pattern of the silver sulfide-germanium ore type solid electrolyte in Example 6 of this application is shown;

[0020] Figure 2 SEM images of the silver-germanium sulfide-type solid electrolyte in Example 6 of this application are shown.

[0021] Figure 3 An AC impedance spectrum of the silver-germanium sulfide-type solid electrolyte in Example 6 of this application is shown. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] As analyzed in the background section of this application, the existing solid electrolytes have the problem of low ionic conductivity. In order to solve the above problem, this application provides a sulfosilver germanium ore type solid electrolyte, its preparation method and battery.

[0024] In a typical embodiment of this application, a sulforaphane-germanium ore-type solid electrolyte is provided, the general chemical formula of which is Li. 5.5+a+2b P 1-a-b M1 a M2 b S 4.5 X 1.5 M1 is selected from elements of Group IVA and / or Group IVB, M2 is selected from any one or more elements of Group IIIB, Group IIIA and Group VA, X is a halogen, 0.1≤a≤0.3, 0.3≤b≤0.5.

[0025] This application effectively increases the cell parameters and lattice volume of the argyrogermanium sulfide solid electrolyte by doping with elements M1 and M2, and significantly extends the bond length between lithium ions and anions in the crystal structure. The increased lattice space provides a wider transport channel for lithium ion migration; the increased bond length between lithium ions and the anion backbone directly weakens the Coulomb attraction between them; these structural changes together lead to a significant reduction in the activation energy barrier for lithium ion migration, thereby contributing to the improvement of the ionic conductivity of the argyrogermanium sulfide solid electrolyte. In particular, by controlling the doping amounts of elements M1 and M2 in the sulfogermanium ore-type solid electrolyte within the aforementioned range, this application helps to further enhance the synergistic effect between elements, thereby further improving the ionic conductivity of the sulfogermanium ore-type solid electrolyte. Applying this sulfogermanium ore-type solid electrolyte to batteries helps to improve the migration rate of ions in the battery, especially meeting the rapid ion transport requirements during high-current charging and discharging, thus improving the high-rate charging and discharging capability of the battery; at the same time, the ion transport resistance is reduced, the internal resistance of the battery is lowered, the Joule heat during charging and discharging is reduced, and the energy efficiency is higher; in addition, it also helps to improve the low-temperature charging and discharging performance of the battery.

[0026] In some embodiments of this application, a can specifically be 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, or any range between two values; b can specifically be 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, or any range between two values.

[0027] In some embodiments of this application, a:b=1:(1.5~2.5), which helps to further enhance the synergistic effect between elements M1 and M2, further increase the cell parameters and lattice volume of the sulfogermanium ore-type solid electrolyte, and extend the bond length between lithium ions and anions in the crystal structure, thereby helping to further improve the ionic conductivity of the sulfogermanium ore-type solid electrolyte, and thus helping to improve the rate performance and low-temperature charge-discharge performance of the battery.

[0028] To further improve the ionic conductivity of the sulfide-germanium ore type solid electrolyte, in some embodiments of this application, M1 is selected from Ge and / or Ti; and / or, M2 is selected from any one or more of Sc, Ga, Al, and Sb; and / or, X is selected from any one or more of F, Cl, Br, and I.

[0029] In some embodiments of this application, M1 is a combination of Ge and Ti elements, and the molar ratio of Ge to Ti elements is (0.4~0.6):(0.4~0.6); and / or, M2 is a combination of Sb and Sc elements, and the molar ratio of Sb to Sc elements is (0.3~0.5):(0.5~0.7); and / or, X is a combination of Cl and I elements, and the molar ratio of Cl to I elements is (0.4~0.6):(0.9~1.1).

[0030] The introduction of Ge (Ge) element helps improve the thermal stability of the material, which is beneficial for stabilizing the high-temperature cubic phase of the silver-germanium sulfide electrolyte. The introduction of Ti (Ti), with its larger size radius, effectively widens the ion transport channels, thus improving ionic conductivity. Simultaneously, the introduction of these lower valence ions leads to more lithium ions entering the unit cell to compensate for the positive charge, resulting in an increase in carrier concentration. Controlling the molar ratio of Ge to Ti within the aforementioned range helps enhance their synergistic effect, thereby further improving the lithium-ion conductivity of the silver-germanium sulfide solid electrolyte. Both Sc (Sc) and Sb elements substitute +5 valence P sites with +3 valence and generate negative charge defects, synergistically constructing Li... + Interval-dominated charge compensation system, in which Sb 3+ Expanding the Li ion radius advantage + Conductive channels lower migration barriers to enhance ionic conductivity, while their lone pairs of electrons can also form electronic barriers to suppress electronic conductivity. 3+ Then, relying on strong matching capabilities, the PS4 is stable. 3- The tetrahedral framework refines the grains and suppresses phase transitions during high-temperature / cycling processes, while simultaneously enriching and forming a stable transition layer at the electrolyte-electrode interface to reduce side reactions. The size difference between Cl and I ions can synergistically regulate lattice parameters, effectively reducing Li... +Transfer the potential barrier and improve the ionic conductivity.

[0031] In some embodiments of the present application, the lithium ionic conductivity of the argyrodite-type solid electrolyte at 25 °C is 4.19×10 -4 ~8.61×10 -3 S·cm -1 .

[0032] The argyrodite-type solid electrolyte with the above ionic conductivity is more suitable for batteries, especially in lithium-ion all-solid-state batteries.

[0033] In another typical embodiment of the present application, a preparation method of the aforementioned argyrodite-type solid electrolyte is provided. The preparation method includes: mixing raw materials including a lithium source, a phosphorus source, a M1 source, a M2 source, a sulfur source, and an X source according to the ratio, and then successively performing ball milling, tabletting, and calcination treatments to obtain the argyrodite-type solid electrolyte.

[0034] In the present application, ball milling can achieve uniform mixing and dispersion of raw materials at the nanoscale, which helps to improve the compositional uniformity and microstructure consistency of the argyrodite-type solid electrolyte. Tabletting helps to improve the density of the material and reduce the porosity, thereby improving the electrochemical performance of the argyrodite-type solid electrolyte. Finally, the argyrodite-type solid electrolyte is obtained through calcination treatment. The preparation method of the present application is simple and has a low cost.

[0035] Including but not limited to, the lithium source is selected from any one or more of lithium sulfide, lithium chloride, and lithium iodide; the phosphorus source is phosphorus pentasulfide; the M1 source is selected from germanium sulfide and / or titanium sulfide; the M2 source is selected from any one or more of scandium sulfide, gallium sulfide, aluminum sulfide, and antimony sulfide; the sulfur source is selected from sulfur powder and / or lithium sulfide; the X source is selected from any one or more of lithium fluoride, lithium chloride, lithium bromide, and lithium iodide.

[0036] In some embodiments of the present application, the temperature during the heating process of the calcination treatment is T. When T≤200 °C, the heating rate is 0.5~1 °C / min; when 200<T≤350 °C, the heating rate is 3~4 °C / min; when T<350 °C, the heating rate is 1.5~2.5 °C / min.

[0037] When T≤200 °C, the heating rate of 0.5~1 °C / min helps to improve the mixing uniformity of the precursor. When 200<T≤350 °C, the heating rate of 3~4 °C / min helps to promote phase transformation. When T<350 °C, the heating rate of 1.5~2.5 °C / min helps to control the crystal growth rate, reduce defects, and improve the crystal integrity, thereby helping to improve the ionic conductivity of the argyrodite-type solid electrolyte.

[0038] In some embodiments of this application, the calcination temperature is 450~550℃; and / or the holding time for calcination is 8~12h.

[0039] Controlling the temperature and time of calcination within the above range helps to promote phase transformation and crystal growth, control grain size and defect density, thereby helping to improve the ionic conductivity of sulfosilver germanite-type solid electrolytes.

[0040] In some embodiments of this application, the ball mill rotation speed is 200~500 rpm; and / or, the ball milling time is 5~24 h; and / or, during the ball milling process, the ball mill jar is scraped once every 1~3 h.

[0041] Controlling the ball mill's rotation speed and time within the aforementioned range helps break up raw material particles and promotes uniform mixing of different raw materials at the nanoscale. Controlling the scraping frequency within the aforementioned range helps break up agglomerated materials and improves the uniformity of raw material distribution within the tank, thereby contributing to improved homogeneity of the silver sulfide-germanium ore type solid electrolyte.

[0042] In some embodiments of this application, the raw materials are mixed by grinding, and the grinding time is 5 to 30 minutes.

[0043] In some embodiments of this application, the ball milling media are selected from zirconium oxide and / or tungsten carbide; and / or, the ball-to-material ratio of the ball milling is (30~60):1.

[0044] In some embodiments of this application, the tableting pressure is 10~30MPa; and / or, the tableting holding time is 10~30min.

[0045] Controlling the tableting pressure and holding time within the above range helps to further reduce the porosity inside the material and increase the density of the material, thereby helping to further improve the ionic conductivity of the silver-germanium sulfide solid electrolyte.

[0046] In another typical embodiment of this application, a battery is provided that contains the aforementioned silver-germanium sulfide-type solid electrolyte.

[0047] Because the battery contains the sulfosilver germanium mineral-type solid electrolyte of this application, the migration rate of ions in the battery is improved, especially during high-current charging and discharging, which can meet the requirements of rapid ion transport, thereby improving the high-rate charging and discharging capability of the battery; at the same time, the ion transport resistance is reduced, the internal resistance of the battery is reduced, the Joule heat during charging and discharging is reduced, and the energy efficiency is higher; in addition, it also helps to improve the low-temperature charging and discharging performance of the battery.

[0048] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0049] Example 1

[0050] Lithium-germanium sulfide solid electrolyte 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at 350 rpm for 12 hours with a ball-to-powder ratio of 40:1 (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0051] Example 2

[0052] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.4 I 1.1 Preparation: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 40:1 and a rotation speed of 350 rpm for 12 hours (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed by heating to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-sulfur germanium ore type solid electrolyte Li. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.4 I 1.1 .

[0053] Example 3

[0054] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.5 P0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.3 I 1.2 Preparation: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 40:1 and a rotation speed of 350 rpm for 12 hours (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed by heating to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-sulfur germanium ore type solid electrolyte Li. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.3 I 1.2 .

[0055] Example 4

[0056] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.5 P 0.4 (Ge 0.4 Ti 0.6 ) 0.2 Sb 0.4 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, titanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 40:1 and a rotation speed of 350 rpm for 12 hours (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 (Ge 0.4 Ti 0.6 ) 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0057] Example 5

[0058] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide.6.5 P 0.4 (Ge 0.6 Ti 0.4 ) 0.2 Sb 0.4 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, titanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 40:1 and a rotation speed of 350 rpm for 12 hours (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 (Ge 0.6 Ti 0.4 ) 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0059] Example 6

[0060] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.5 P 0.4 (Ge 0.6 Ti 0.4 ) 0.2 (Sb 0.3 Sc 0.7 ) 0.4 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, titanium sulfide, scandium trisulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 40:1 and a rotation speed of 350 rpm for 12 hours (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 (Ge 0.6 Ti 0.4 ) 0.2 (Sb 0.3 Sc 0.7 ) 0.4S 4.5 Cl 0.5 I1.

[0061] Example 7

[0062] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.5 P 0.4 (Ge 0.6 Ti 0.4 ) 0.2 (Sb 0.5 Sc 0.5 ) 0.4 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, titanium sulfide, scandium trisulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 40:1 and a rotation speed of 350 rpm for 12 hours (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 (Ge 0.6 Ti 0.4 ) 0.2 (Sb 0.5 Sc 0.5 ) 0.4 S 4.5 Cl 0.5 I1.

[0063] Example 8

[0064] Lithium-germanium sulfide solid electrolyte 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 40:1 and a rotation speed of 350 rpm for 12 hours (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 0.5℃ / min, then to 350℃ at a rate of 4℃ / min, and finally to 500℃ at a rate of 1.5℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.5 P0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0065] Example 9

[0066] The difference from Example 1 is that the heating process during calcination eliminates the use of different heating rates at different temperature ranges. Instead, the temperature is directly raised to 500°C at a heating rate of 2°C / min and held for 10 hours, ultimately yielding the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0067] Example 10

[0068] The difference from Example 1 is that the calcination temperature was 550°C and the holding time was 8 hours, ultimately yielding the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0069] Example 11

[0070] The difference from Example 1 is that the calcination temperature was 450°C and the holding time was 12 hours, ultimately yielding the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0071] Example 12

[0072] The difference from Example 1 is that the calcination temperature was 600℃ and the holding time was 5 hours, ultimately yielding the silver-germanium sulfide-type solid electrolyte Li. 6.5 P 0.4 Ge 0.2 Sb 0.4 S 4.5 Cl 0.5 I1.

[0073] Example 13

[0074] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.6 P 0.4Ge 0.1 Sb 0.5 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at 500 rpm for 5 hours with a ball-to-powder ratio of 30:1 (with wall scraping every hour). The powder was then pressed into tablets at 10 MPa and held for 30 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.6 P 0.4 Ge 0.1 Sb 0.5 S 4.5 Cl 0.5 I1.

[0075] Example 14

[0076] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.4 P 0.4 Ge 0.3 Sb 0.3 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at a ball-to-powder ratio of 60:1 and a rotation speed of 200 rpm for 24 hours (with wall scraping every 3 hours). The powder was then pressed into tablets at 30 MPa and held for 10 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.4 P 0.4 Ge 0.3 Sb 0.3 S 4.5 Cl 0.5 I1.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.65 P 0.4 Ge 0.05 Sb 0.55 S 4.5 Cl 0.5Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at 350 rpm for 12 hours with a ball-to-powder ratio of 40:1 (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.65 P 0.4 Ge 0.05 Sb 0.55 S 4.5 Cl 0.5 I1.

[0079] Comparative Example 2

[0080] The difference from Example 1 is that the Li-type solid electrolyte is silver-germanium sulfide. 6.3 P 0.4 Ge 0.4 Sb 0.2 S 4.5 Cl 0.5 Preparation of I1: Lithium sulfide, lithium chloride, lithium iodide, phosphorus pentasulfide, germanium sulfide, and antimony trisulfide were mixed in stoichiometric ratio and ground for 20 minutes. Then, high-energy ball milling was performed at 350 rpm for 12 hours with a ball-to-powder ratio of 40:1 (with wall scraping every 2 hours). The powder was then pressed into tablets at 20 MPa and held for 15 minutes. Finally, calcination was performed, with the temperature increased to 200℃ at a rate of 1℃ / min, then to 350℃ at a rate of 3℃ / min, and finally to 500℃ at a rate of 2℃ / min and held for 10 hours to obtain the silver-germanium sulfide-type solid electrolyte Li. 6.3 P 0.4 Ge 0.4 Sb 0.2 S 4.5 Cl 0.5 I1.

[0081] Performance testing

[0082] The lithium-ion conductivity testing procedure is as follows: At 25℃, 100mg of solid electrolyte powder is evenly spread into the test mold, with stainless steel rods serving as current collectors at both ends. The assembled mold is placed in a press, and vertical pressure is applied to cold-press the electrolyte powder into a 0.8mm thick sheet. After tightening the mold screws, the mold is assembled into a symmetrical battery structure for impedance testing. An AC impedance tester (Solartron 1260A) is used to perform AC impedance testing on this structure, with the test frequency range set to 1Hz~10Hz. 7At Hz, an AC bias voltage of 20mV was applied, and the impedance spectrum was obtained. After the test, the electrolyte sheet was removed from the mold and its actual thickness was accurately measured. The impedance value R was calculated by fitting the impedance spectrum, and then calculated according to the formula σ=L / (R). S) Calculate the lithium-ion conductivity of the electrolyte (where: σ is the ion conductivity, L is the thickness of the electrolyte sheet, R is the impedance value, and S is the contact area between the electrolyte sheet and the current collector).

[0083] The lithium-ion conductivity of the sulfosilver germanite-type solid electrolytes prepared in the examples and comparative examples was tested, and the test results are shown in Table 1.

[0084] Table 1

[0085]

[0086] Figure 1 The XRD pattern of the silver-germanium sulfide-type solid electrolyte in Example 6 of this application is shown below. Figure 1 As can be seen from the data, the characteristic peaks of the sulfosilver germanium ore type solid electrolyte correspond to the peak positions of the standard card, and there are no other impurity peaks, indicating that the sulfosilver germanium ore type solid electrolyte was successfully synthesized.

[0087] Figure 2 This is a SEM image of the silver-germanium sulfide-type solid electrolyte in Example 6 of this application. Figure 2 As can be seen, the particle size distribution of the solid electrolyte is 20~30μm.

[0088] Figure 3 The AC impedance spectrum of the silver-germanium sulfide-type solid electrolyte in Example 6 of this application is shown below. Figure 3 The ionic conductivity can be calculated to be 8.61 × 10⁻⁶. -3 S·cm -1 .

[0089] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0090] This application effectively increases the cell parameters and lattice volume of the argyrogermanium sulfide solid electrolyte by doping with elements M1 and M2, and significantly extends the bond length between lithium ions and anions in the crystal structure. The increased lattice space provides a wider transport channel for lithium ion migration; the increased bond length between lithium ions and the anion backbone directly weakens the Coulomb attraction between them; these structural changes together lead to a significant reduction in the activation energy barrier for lithium ion migration, thereby contributing to the improvement of the ionic conductivity of the argyrogermanium sulfide solid electrolyte. In particular, by controlling the doping amounts of elements M1 and M2 in the sulfogermanium ore-type solid electrolyte within the aforementioned range, this application helps to further enhance the synergistic effect between elements, thereby further improving the ionic conductivity of the sulfogermanium ore-type solid electrolyte. Applying this sulfogermanium ore-type solid electrolyte to batteries helps to improve the migration rate of ions in the battery, especially meeting the rapid ion transport requirements during high-current charging and discharging, thus improving the high-rate charging and discharging capability of the battery; at the same time, the ion transport resistance is reduced, the internal resistance of the battery is lowered, the Joule heat during charging and discharging is reduced, and the energy efficiency is higher; in addition, it also helps to improve the low-temperature charging and discharging performance of the battery.

[0091] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sulforaphane-germanium ore type solid electrolyte, characterized in that, The chemical formula of the sulfide-germanium ore type solid electrolyte is Li 5.5+a+2b P 1-a-b M1 a M2 b S 4.5 X 1.5 M1 is selected from elements of Group IVA and / or Group IVB, M2 is selected from any one or more elements of Group IIIB, Group IIIA and Group VA, X is a halogen, 0.1≤a≤0.3, 0.3≤b≤0.

5.

2. The sulfide-germanium ore type solid electrolyte according to claim 1, characterized in that, M1 is selected from Ge element and / or Ti element; and / or, M2 is selected from any one or more of Sc element, Ga element, Al element, and Sb element; and / or, X is selected from any one or more of F element, Cl element, Br element, and I element.

3. The sulfide-germanium ore type solid electrolyte according to claim 2, characterized in that, M1 is a combination of Ge element and Ti element, and the molar ratio of Ge element to Ti element is (0.4~0.6):(0.4~0.6); and / or, M2 is a combination of Sb element and Sc element, and the molar ratio of Sb element to Sc element is (0.3~0.5):(0.5~0.7); and / or, X is a combination of Cl element and I element, and the molar ratio of Cl element to I element is (0.4~0.6):(0.9~1.1).

4. The sulfide-germanium ore type solid electrolyte according to any one of claims 1 to 3, characterized in that, The lithium-ion conductivity of the silver-germanium sulfide-type solid electrolyte at 25°C is 4.19 × 10⁻⁶. -4 ~8.61×10 -3 S·cm -1 .

5. A method for preparing a sulfide-germanium ore-type solid electrolyte according to any one of claims 1 to 4, characterized in that, The preparation method includes: Mixing raw materials including a lithium source, a phosphorus source, an M1 source, an M2 source, a sulfur source, and an X source according to the ratio, and then successively performing ball milling, tabletting, and calcination treatments to obtain the argyrodite-type solid electrolyte.

6. The method for preparing the sulfide-germanium ore-type solid electrolyte according to claim 5, characterized in that, The temperature during the heating process of the calcination treatment is T. When T≤200°C, the heating rate is 0.5~1°C / min; when 200<T≤350°C, the heating rate is 3~4°C / min; when T>350°C, the heating rate is 1.5~2.5°C / min.

7. The method for preparing the sulfide-germanium ore-type solid electrolyte according to claim 5, characterized in that, The temperature of the calcination treatment is 450~550°C; and / or, the heat preservation time of the calcination treatment is 8~12h.

8. The method for preparing the sulfide-germanium ore-type solid electrolyte according to any one of claims 5 to 7, characterized in that, The rotation speed of the ball milling is 200~500rpm; and / or, the time of the ball milling is 5~24h; and / or, during the ball milling process, the ball milling tank is scraped once every 1~3h.

9. The method for preparing the sulfide-germanium ore-type solid electrolyte according to any one of claims 5 to 7, characterized in that, The pressure of the tabletting is 10~30MPa; and / or, the pressure holding time of the tabletting is 10~30min.

10. A battery, characterized in that, The battery contains the argyrodite-type solid electrolyte according to any one of claims 1 to 4.

Images