A tin-modified sulfide solid electrolyte, a preparation method thereof, and a full solid-state battery
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INNOVATION CENTER OF YANGTZE RIVER DELTA ZHEJIANG UNIVERSITY
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-16
Smart Images
Figure CN122224936A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of solid electrolyte technology, and in particular to a tin-modified sulfide solid electrolyte, its preparation method, and an all-solid-state battery. Background Technology
[0002] With the booming development of electric vehicles and mobile electronic devices, the market demand for high-performance solid-state batteries is growing rapidly. Sulfide solid electrolytes, with their high ionic conductivity and good mechanical properties, have become key candidate materials for next-generation solid-state batteries. However, existing sulfide solid electrolytes still have some problems that need to be solved. For example, their ionic conductivity still has room for improvement, and their interfacial compatibility with lithium metal anodes is poor, which limits the cycle life and safety performance of all-solid-state batteries. Summary of the Invention
[0003] This disclosure provides a tin-modified sulfide solid electrolyte, its preparation method, and an all-solid-state battery, thereby addressing at least one of the technical problems existing in the prior art.
[0004] In a first aspect, this application provides a method for preparing a tin-modified sulfide solid electrolyte, the method comprising:
[0005] Under an inert atmosphere, Sn source and sulfide solid electrolyte are mixed at a mass ratio of 1%~10%:1 and ball-milled to obtain precursor powder; The precursor powder was sintered and cooled under a protective atmosphere to obtain a tin-modified sulfide solid electrolyte.
[0006] In one embodiment, the Sn source is one or more of metallic Sn powder, Sn sulfide, and Sn halide; The chemical formula of the sulfide solid electrolyte is Li₂S-P₂S₅, Li₆PS₅X, where X is Cl, Br, or I. Based on the variants derived from Li₆PS₅X, Li 10 GeP2S 12 Li 10 SnP2S 12 and Li 10 SiP2S 12 One of them.
[0007] In one embodiment, the sulfide of Sn is SnS2, SnS, or (NH4)4Sn4S. 10 Li4Sn4S 10 One or more of the following; The Sn halide is one or more of SnI4, SnF2, and SnCl2.
[0008] In one embodiment, the sintering temperature is 400~550℃ and the sintering time is 8~20h.
[0009] In one embodiment, the sintering temperature is 450~550℃.
[0010] In one embodiment, the ball mill rotates at a speed of 1000-2000 r / min and the milling time is 10-60 min.
[0011] In one embodiment, the ball mill rotates at a speed of 1500-1800 r / min and the milling time is 20-40 min.
[0012] In one embodiment, the precursor powder has a particle size of 2~15μm.
[0013] In one embodiment, the protective atmosphere is one or a mixture of argon and helium.
[0014] Secondly, this disclosure provides a tin-modified sulfide solid electrolyte, which is obtained by any of the preparation methods described above.
[0015] Thirdly, this application provides an all-solid-state battery, including a tin-modified sulfide solid electrolyte or a tin-modified sulfide solid electrolyte prepared by any of the above preparation methods.
[0016] Compared with the prior art, the advantages of this application are: 1) The method of this application significantly improves the ionic conductivity of tin-modified sulfide solid electrolyte. This improvement is mainly due to the doping of Sn source and the finely controlled sintering process parameters, such as appropriate doping ratio, high-temperature sintering temperature and time. These factors work together to optimize the internal structure of tin-modified sulfide solid electrolyte and reduce the obstacle to ion transport, thereby achieving a significant improvement in ionic conductivity.
[0017] 2) This application also effectively enhances the interfacial compatibility between the tin-modified sulfide solid electrolyte and the lithium metal anode. Sn modification improves the interfacial contact between the electrolyte and the anode, reduces interfacial resistance, and enhances interfacial stability, thereby extending the cycle life of the all-solid-state battery and improving its safety performance. This advantage is mainly attributed to the selection of the Sn source and its thorough mixing with the sulfide solid electrolyte, as well as the precisely controlled high-energy ball milling and high-temperature sintering processes.
[0018] 3) The preparation method of this application is simple to operate and easy to industrialize. The raw materials used are readily available, no complex equipment is required in the preparation process, and the process parameters are easy to control, which is conducive to large-scale production, reduces production costs, and improves production efficiency. This advantage mainly stems from the rational design and optimization of the preparation method, as well as the precise control of key steps.
[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description
[0020] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which: In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.
[0021] Figure 1 The XRD patterns and scanning electron microscope images of the tin-modified sulfide solid electrolytes of Examples 1-4 of this disclosure are shown; Figure 2 The EIS and IT test results of the symmetrical cell of Embodiment 1 of this disclosure are shown; Figure 3 The constant current charge-discharge test results of the lithium symmetric battery of Embodiment 1 of this disclosure are shown; Figure 4 The performance test results of the all-solid-state battery of Embodiment 1 of this disclosure are shown.
[0022] Figure 5 The X-ray photoelectron spectroscopy (XPS) of Embodiment 1 of this disclosure and the sulfide solid electrolyte Li6PS5Cl is shown.
[0023] in, Figure 1 In this context, 2θ represents the diffraction angle, and Intensity represents the intensity. Figure 2 In this context, Z′ / ohm represents the real part of the impedance in ohms, -Z'' / ohm represents the imaginary part (negative value) of the impedance in ohms, Time represents time, Current represents current, 1000 / T represents 1000 times the reciprocal of temperature, ln(σT) represents the natural logarithm of the product of conductivity and temperature, Current collector represents the current collector, carbon-coated aluminum foil represents carbon-coated aluminum foil, and solid electrolyte represents tin-modified sulfide solid electrolyte. Figure 3In this context, Current density represents current density, and Potential represents electric potential. Figure 4 In this context, "specific capacity" refers to the specific capacity, "Voltage" refers to the voltage, and "Cycle number" refers to the number of cycles. Figure 5 Binding Energy in this context refers to the binding energy. Detailed Implementation
[0024] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0025] Because the ionic conductivity of existing sulfide solid electrolytes still has room for improvement, and their interfacial compatibility with lithium metal anodes is poor, the cycle life and safety performance of all-solid-state batteries are limited. To overcome these technical challenges, researchers have been striving to find effective ways to modify sulfide solid electrolytes. It is against this technical background that this invention was developed. This invention provides a tin (Sn)-modified sulfide solid electrolyte for use in all-solid-state batteries and its preparation method. By doping Sn into the sulfide solid electrolyte and precisely controlling the sintering process parameters, the internal structure of the electrolyte can be optimized, reducing ion transport resistance and thus significantly improving ionic conductivity. Simultaneously, this modification method can also improve the interfacial contact between the electrolyte and the lithium metal anode, reduce interfacial resistance, enhance interfacial stability, and further improve the cycle life and safety performance of all-solid-state batteries.
[0026] Based on this, in a first aspect, this disclosure provides a method for preparing a tin-modified sulfide solid electrolyte, the method comprising: Step 1), under an inert atmosphere, mix Sn source and sulfide solid electrolyte at a mass ratio of 1%~10%:1 and ball mill to obtain precursor powder; Step 2) The precursor powder is sintered and cooled under a protective atmosphere to obtain tin-modified sulfide solid electrolyte.
[0027] In one possible embodiment, in step 1), the Sn source is one or more of metallic Sn powder, Sn sulfides, and Sn halides; the sulfide solid electrolyte is a disulfide solid electrolyte Li₂S-P₂S₅, Li₆PS₅X, where X is Cl, Br, or I, and is a variant derived from Li₆PS₅X. 10 GeP2S12 Li 10 SnP2S 12 and Li 10 SiP2S 12 One of them.
[0028] Preferably, the Sn source is metallic Sn powder because it has high reactivity and uniform doping effect.
[0029] Preferably, the sulfide of Sn is SnS2, SnS, or (NH4)4Sn4S 10 Li4Sn4S 10 One or more of the following; preferably, the halides of Sn are one or more of SnI4, SnF2, and SnCl2.
[0030] Preferably, the mass ratio of Sn source to sulfide solid electrolyte is 1-5%:1. Exemplarily, the mass ratio of Sn source to sulfide solid electrolyte is 1%:1, 2%:1, 3%:1, 4%:1, 5%:1, 6%:1, 7%:1, 8%:1, 9%:1, or 10%:1.
[0031] For example, the inert atmosphere in step 1) includes, but is not limited to, argon and helium atmospheres.
[0032] In one embodiment, in step 2), the sintering temperature is 400~550℃ and the sintering time is 8~20h. Preferably, the sintering temperature is 450~550℃. Exemplarily, the sintering temperatures are 400℃, 450℃, 500℃, and 550℃.
[0033] In one embodiment, in step 1), the ball milling speed is 1000~2000 r / min, and the milling time is 10~60 min, to ensure that the Sn source and the sulfide solid electrolyte are fully mixed and the particles are refined. Exemplarily, the ball milling speed is 1000 r / min, 1100 r / min, 1200 r / min, 1300 r / min, 1400 r / min, 1500 r / min, 1600 r / min, 1700 r / min, 1800 r / min, 1900 r / min, 2000 r / min, etc. Preferably, the ball milling speed is 1500~1800 r / min, and the milling time is 20~40 min.
[0034] In one embodiment, in step 1), the particle size of the precursor powder is 2~15μm. Exemplarily, the particle size of the precursor powder is 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, or 15μm.
[0035] In one embodiment, in step 2), the protective atmosphere is one or a mixture of argon and helium. Preferably, the protective atmosphere is argon, as using argon can prevent the material from oxidizing at high temperatures.
[0036] This application provides a method for preparing a tin (Sn)-modified sulfide solid electrolyte applicable to all-solid-state batteries. By doping the sulfide solid electrolyte with a Sn source and precisely controlling sintering process parameters, such as the precise Sn source doping ratio, high-temperature sintering temperature, and time, these factors work together to optimize the internal structure of the electrolyte, reduce ion transport resistance, and thus significantly improve ionic conductivity. Simultaneously, this method for preparing a tin-modified sulfide solid electrolyte also improves the interfacial contact between the tin-modified sulfide solid electrolyte and the lithium metal anode, enhances their interfacial compatibility, reduces interfacial resistance, and enhances interfacial stability, thereby improving the cycle life and safety performance of the all-solid-state battery.
[0037] Furthermore, the preparation method described in this application is simple to operate and easy to industrialize. The raw materials used are readily available, no complex equipment is required during the preparation process, and the process parameters are easy to control, which is conducive to large-scale production, reduces production costs, and improves production efficiency. This advantage mainly stems from the rational design and optimization of the preparation method, as well as the precise control of key steps.
[0038] Secondly, this application provides a tin-modified sulfide solid electrolyte prepared using the above method. The lithium-ion conductivity of the tin-modified sulfide solid electrolyte prepared using the method of this application is 4-7 mS / cm.
[0039] Thirdly, this application provides an all-solid-state battery comprising a tin-modified sulfide solid electrolyte prepared by the above-described preparation method.
[0040] Because the tin-modified sulfide solid electrolyte of this application has good ionic conductivity, it also improves the interfacial compatibility with the lithium metal anode, reduces interfacial resistance, and enhances interfacial stability, thereby significantly improving the cycle performance and safety performance of the all-solid-state battery.
[0041] The present application will be further described in detail below with reference to the embodiments.
[0042] Example 1 A tin-modified sulfide solid electrolyte is prepared by the following method, comprising: Step 1): In a vacuum glove box (argon atmosphere), metal Sn powder and sulfide solid electrolyte Li6PS5Cl are mixed at a mass ratio of 3%:1 and placed in a ball mill jar for high-energy ball milling at a speed of 1500 r / min for 30 min to obtain precursor powder with a particle size of 2~15 μm.
[0043] Step 2) The precursor powder is sintered at high temperature under an argon protective atmosphere at 500℃ for 15 hours. After cooling, a tin-modified sulfide solid electrolyte is obtained. The particle size of the tin-modified sulfide solid electrolyte is 2~15μm.
[0044] In Example 1, by adjusting the Sn source doping ratio to 3 wt%, the resulting tin-modified sulfide solid electrolyte material achieved a lithium-ion conductivity of 6.57 mS / cm, exhibiting excellent ionic conductivity. Furthermore, the interfacial compatibility between the tin-modified sulfide solid electrolyte and the lithium metal anode was significantly improved, and the critical current density reached 3.8 mA / cm. -2 The first-charge specific capacity for the all-solid-state battery is 284.42 mAh.g. -1 The first-cycle coulombic efficiency is 76.97%, which effectively improves the cycle performance and safety performance of the all-solid-state battery.
[0045] Example 2 A tin-modified sulfide solid electrolyte is prepared by the following method, comprising: Step 1): In a vacuum glove box (argon atmosphere), SnS2 and sulfide solid electrolyte Li6PS5Cl are mixed at a mass ratio of 1%:1 and placed in a ball mill jar for high-energy ball milling at a speed of 1800 r / min for 20 min to obtain precursor powder with a particle size of 2~10 μm.
[0046] Step 2) The precursor powder was sintered at high temperature under an argon protective atmosphere. The sintering temperature was set at 550℃ and the sintering time was 10 hours. After cooling, tin-modified sulfide solid electrolyte was obtained. The particle size of the tin-modified sulfide solid electrolyte was 2~10μm.
[0047] In Example 2, by adjusting the Sn source doping ratio to 1 wt%, the lithium-ion conductivity of the obtained tin-modified sulfide solid electrolyte material reached 5.69 mS / cm. Furthermore, the interfacial compatibility between the tin-modified sulfide solid electrolyte and the lithium metal anode was effectively improved, and the critical current density reached 3.6 mA / cm. -2 The first-charge specific capacity for the all-solid-state battery is 270.45 mAh.g. -1 In the first lap, the efficiency of the Coulomb was 76.65%.
[0048] Example 3 A tin-modified sulfide solid electrolyte is prepared by the following method, comprising: Step 1): In a vacuum glove box environment (argon atmosphere), SnS and sulfide solid electrolyte Li6PS5Cl are mixed at a mass ratio of 2%:1 and placed in a ball mill jar for high-energy ball milling. The ball milling speed is 1600 r / min and the ball milling is continued for 40 min to obtain precursor powder with a particle size of 2~12 μm.
[0049] Step 2) The precursor powder was sintered at high temperature in an argon protective atmosphere at 520°C for 12 hours. After cooling, tin-modified sulfide solid electrolyte was obtained. The particle size of the tin-modified sulfide solid electrolyte was 2~12 μm.
[0050] In Example 3, by precisely controlling the Sn source doping amount to 2 wt%, this tin-modified sulfide solid electrolyte material exhibited excellent ionic conductivity, achieving a lithium-ion conductivity of 5.62 mS / cm. It also effectively improved the interfacial compatibility with the lithium metal anode, achieving a critical current density of 3.2 mA / cm. -2 This ensures the cycle durability and safety reliability of all-solid-state batteries; the first-charge specific capacity of the all-solid-state battery is 264.93 mAh.g. -1 In the first round, the efficiency of the Cullen was 76.90%.
[0051] Example 4 A tin-modified sulfide solid electrolyte is prepared by the following method, comprising: Step 1): In a vacuum glove box (argon atmosphere), SnCl2 and sulfide solid electrolyte Li6PS5Cl are mixed at a mass ratio of 4%:1 and placed in a ball mill jar for high-energy ball milling at a speed of 1700 r / min for 30 min to obtain precursor powder with a particle size of 2~13 μm.
[0052] Step 2) The precursor powder is transferred to a protective atmosphere filled with argon for high-temperature sintering. The sintering temperature is set at 480℃, and the sintering time is strictly controlled to be 18 hours. After the cooling process is completed, the tin-modified sulfide solid electrolyte can be obtained. The particle size of the tin-modified sulfide solid electrolyte is 2~13μm.
[0053] In Example 4, by precisely controlling the doping ratio of the Sn source to 4 wt%, the resulting tin-modified sulfide solid electrolyte material not only exhibited excellent ionic conductivity, with a lithium-ion conductivity of 5.79 mS / cm and a critical current density reaching 3.4 mA / cm, but also demonstrated superior ionic conductivity. -2 The first-charge specific capacity for the all-solid-state battery is 253.15 mAh.g. -1 In the first round, the efficiency of the Cullen was 75.92%.
[0054] Example 5 This Example 5 is largely the same as Example 1, except that the chemical formula of the sulfide solid electrolyte in step 1) is Li6PS5Br.
[0055] In Example 5, a tin-modified sulfide solid electrolyte was prepared, with a lithium-ion conductivity of 5.83 mS / cm and a critical current density of 2.6 mA / cm². -2 The first-charge specific capacity for the all-solid-state battery is 260.32 mAh.g. -1 In the first lap, Cullen's efficiency was 75.29%.
[0056] Example 6 This embodiment 6 is largely the same as embodiment 1, except that the chemical formula of the sulfide solid electrolyte in step 1) is Li6PS5I.
[0057] In Example 6, a tin-modified sulfide solid electrolyte was prepared, with a lithium-ion conductivity of 5.68 mS / cm and a critical current density of 3.0 mA / cm. -2 The first-charge specific capacity for the all-solid-state battery is 257.45 mAh.g. -1 In the first lap, the efficiency of the Cullen team was 74.62%.
[0058] Example 7 A tin-modified sulfide solid electrolyte is prepared by the following method, comprising: Step 1), in a vacuum glove box (argon atmosphere), SnCl2 and the sulfide solid electrolyte Li 10 GeP2S 12 (abbreviated as LGPS) The precursor powder was mixed at a mass ratio of 3%:1 and placed in a ball milling jar for high-energy ball milling. The ball milling speed was set to 1700 r / min and the ball milling time was 30 minutes to obtain the precursor powder with a particle size of 2~10μm.
[0059] Step 2) The precursor powder is transferred to a protective atmosphere filled with argon for high-temperature sintering. The sintering temperature is set at 500℃ and the sintering time is strictly controlled to be 18 hours. After the cooling process is completed, tin-modified sulfide solid electrolyte with a particle size of 2~10 μm is obtained.
[0060] In Example 7, by precisely controlling the doping ratio of the Sn source to 3 wt%, this tin-modified sulfide solid electrolyte material not only exhibits excellent ionic conductivity, with a lithium-ion conductivity of 6.02 mS / cm and a critical current density reaching 3.2 mA / cm, but also demonstrates superior performance. -2 The first-charge specific capacity for the all-solid-state battery is 256.82 mAh.g. -1 In the first lap, the efficiency of the Coulomb was 76.35%.
[0061] Example 8 This embodiment 8 is largely the same as embodiment 1, except that in step 1), the mass ratio of Sn source to sulfide solid electrolyte is 9%:1.
[0062] In Example 8, a tin-modified sulfide solid electrolyte was prepared. This tin-modified sulfide solid electrolyte exhibited a lithium-ion conductivity of 5.81 mS / cm and a critical current density of 2.8 mA / cm². -2 The first-charge specific capacity for the all-solid-state battery is 262.37 mAh.g. -1 In the first lap, the efficiency of the Coulomb was 75.86%.
[0063] Example 9 A tin-modified sulfide solid electrolyte is prepared by the following method, comprising: Step 1): In a vacuum glove box (argon atmosphere), metal Sn powder and sulfide solid electrolyte Li2S-P2S5 are mixed at a mass ratio of 3%:1 and placed in a ball mill jar for high-energy ball milling at a speed of 1500 r / min for 30 min to obtain precursor powder with a particle size of 5~10 μm.
[0064] Step 2) The precursor powder is placed in an argon protective atmosphere for high-temperature sintering at a temperature of 500°C for 15 hours. After cooling, tin-modified sulfide solid electrolyte is obtained with a particle size of 5~10 μm.
[0065] In Example 9, by adjusting the Sn source doping ratio to 3 wt%, the resulting tin-modified sulfide solid electrolyte achieved a lithium-ion conductivity of 5.93 mS / cm, exhibiting excellent ionic conductivity. Furthermore, the interfacial compatibility with the lithium metal anode was significantly improved, and the critical current density reached 3.0 mA / cm. -2The first-charge specific capacity for the all-solid-state battery is 259.62 mAh.g. -1 In the first lap, the efficiency of the Cullen team was 75.63%.
[0066] Comparative Example 1 Comparative Example 1 is largely the same as Example 1, except that the protective atmosphere for high-temperature sintering was changed in Comparative Example 1, and sintering was carried out under a nitrogen protective atmosphere.
[0067] In Comparative Example 1, a tin-modified sulfide solid electrolyte was prepared. However, due to the side reaction between nitrogen gas and the material, a small amount of lithium-nitrogen compounds, such as lithium nitride (Li3N), were generated. If Li3N is present in the grain boundaries of the tin-modified sulfide solid electrolyte, it will provide a channel for the growth of lithium dendrites, greatly increasing the risk of internal short circuits in the battery. The tin-modified sulfide solid electrolyte sintered under a nitrogen protective atmosphere exhibited significantly reduced performance, with an extremely low lithium-ion conductivity of only 2.81 mS / cm, and extremely poor interfacial compatibility with the lithium metal anode, resulting in a critical current density of only 2.0 mA / cm. -2 The first-charge specific capacity for the all-solid-state battery is 236.15 mAh g. -1 The first-cycle coulomb efficiency was 70.92%. This result highlights the importance of the protective atmosphere selection in the high-temperature sintering process and further verifies the rationality of using argon as the protective atmosphere in this invention.
[0068] Comparative Example 2 Comparative Example 2 is largely the same as Example 1, except that the sintering temperature in step 2) is set to 350°C.
[0069] In Comparative Example 2, a tin-modified sulfide solid electrolyte was prepared, but its ionic conductivity was significantly reduced, with the lithium-ion conductivity far below the expected value, at only 3.35 mS / cm. Furthermore, the interfacial compatibility between the tin-modified sulfide solid electrolyte and the lithium metal anode was also significantly insufficient, with a critical current density of only 1.6 mA / cm². -2 The first-charge specific capacity for the all-solid-state battery is 225.17 mAh.g. -1 The first-cycle coulombic efficiency was 73.86%. This result highlights the crucial role of high-temperature sintering temperature in ensuring the excellent performance of tin-modified sulfide solid electrolytes, and further supports the rationality of the preferred sintering temperature range in this application.
[0070] Comparative Example 3 Comparative Example 3 is largely the same as Example 1, except that the sintering temperature is set to 600°C.
[0071] In Comparative Example 3, a tin-modified sulfide solid electrolyte was prepared. The resulting tin-modified sulfide solid electrolyte material exhibited significantly reduced ionic conductivity, with a lithium-ion conductivity far below the expected value, at only 2.65 mS / cm. This indicates that excessively high sintering temperatures lead to structural collapse of the electrolyte material itself. Furthermore, the interfacial compatibility between the tin-modified sulfide solid electrolyte and the lithium metal anode was also significantly insufficient, with a critical current density of only 1.8 mA / cm². -2 The first-charge specific capacity for the all-solid-state battery is 210.43 mAh.g. -1 The first-cycle coulombic efficiency was 73.15%. This result highlights the crucial role of high-temperature sintering temperature in ensuring excellent performance of electrolyte materials, and further supports the rationality of the preferred sintering temperature range in this application.
[0072] Comparative Example 4 Comparative Example 4 is largely the same as Example 1, except that the Sn source doping ratio is adjusted to 0.5%.
[0073] Comparative Example 4 prepared a tin-modified sulfide solid electrolyte with a lithium-ion conductivity of 2.94 mS / cm and a critical current density of 1.4 mA / cm². -2 The first-charge specific capacity for the all-solid-state battery is 224.29 mAh.g. -1 The first-cycle coulombic efficiency was 74.81%. This result highlights the crucial role of the Sn source doping ratio in ensuring excellent performance of the electrolyte material, and further supports the rationality of the optimal Sn source doping ratio in this application.
[0074] Comparative Example 5 Comparative Example 5 is largely the same as Example 1, except that the Sn source doping ratio is adjusted to 12%.
[0075] Comparative Example 5 prepared a tin-modified sulfide solid electrolyte with a lithium-ion conductivity of 2.53 mS / cm and a critical current density of 1.2 mA / cm². -2 The first-charge specific capacity for the all-solid-state battery is 214.46 mAh.g. -1 The first-cycle coulombic efficiency was 72.43%. This result highlights the crucial role of the Sn source doping ratio in ensuring excellent performance of the electrolyte material, and further supports the rationality of the preferred Sn source doping ratio in this application.
[0076] Performance test Test 1 The tin-modified sulfide solid electrolytes prepared in Examples 1-4 were subjected to XRD and scanning electron microscopy tests, and the results are as follows: Figure 1 As shown.
[0077] Figure 1 (a) XRD test results of the tin-modified sulfide solid electrolytes prepared in Examples 1-4. Figure 1 (b) Scanning electron microscopy results of the tin-modified sulfide solid electrolyte prepared in Example 1. Figure 1 (c) Scanning electron microscopy results of the tin-modified sulfide solid electrolyte prepared in Example 2. Figure 1 (d) is the scanning electron microscopy result of the tin-modified sulfide solid electrolyte prepared in Example 3. Figure 1 (e) is the scanning electron microscope result of the tin-modified sulfide solid electrolyte prepared in Example 4.
[0078] from Figure 1 It can be seen from the XRD spectra that the characteristic peaks of Examples 1 to 4 are basically consistent with the characteristic peaks of Li6PS5Cl. Furthermore, it can be observed from the scanning electron microscope images that the particle size of the tin-modified sulfide solid electrolytes of Examples 1 to 4 is maintained at 2~15 μm.
[0079] Furthermore, the tin-modified sulfide solid electrolyte and the sulfide solid electrolyte Li6PS5Cl prepared in Example 1 were subjected to X-ray photoelectron spectroscopy (XPS) tests, and the results are as follows: Figure 5 As shown. Figure 5 In the diagram, ad is the P 2p, S 2p, Cl 2p, Sn 3d spectrum of the tin-modified sulfide solid electrolyte, and eh is the P 2p, S 2p, Cl 2p, Sn 3d spectrum of the sulfide solid electrolyte Li6PS5Cl.
[0080] from Figure 5 The XPS analysis results show that the P 2p, S 2p, and Cl 2p valence state distributions of the tin-modified sulfide solid electrolyte in Example 1 are consistent with those of the sulfide solid electrolyte Li6PS5Cl. This indicates that the modification did not affect the lattice of the sulfide solid electrolyte Li6PS5Cl, which is also consistent with the results obtained by XRD.
[0081] Test 2 Symmetric cells were prepared using the tin-modified sulfide solid electrolytes obtained in Examples 1-9 and Comparative Examples 1-5, respectively.
[0082] Assembly method of the symmetric cell: 100 mg of tin-modified sulfide solid electrolyte powder was accurately weighed and placed in a mold cavity with an inner diameter of 10 mm. Then, a 10 mm diameter carbon-coated aluminum foil was placed on both the upper and lower surfaces of the tin-modified sulfide solid electrolyte powder as blocking electrodes. Finally, the cell was held at 150 MPa for 10 min to complete the integrated molding of the cell and optimize the electrode interface contact. The assembled symmetric cell was then connected to an electrochemical workstation for EIS (electrochemical impedance spectroscopy) and IT (chronoamperometry) tests. The results are as follows: Figure 2 As shown in Table 1.
[0083] Formula for calculating ionic conductivity:
[0084] in, denoted as ionic conductivity (mS / cm), L as thickness of electrolyte sheet (cm), R as impedance (Ohm), and r as radius of electrode sheet (cm).
[0085] Formula for calculating electronic conductivity:
[0086] in, ρ is electronic conductivity, in S / cm; L is the thickness of the electrolyte sheet, in cm; I is the steady-state current, in A; U is the voltage, in V; and r is the radius of the electrode sheet, in cm.
[0087] in, Figure 2 The EIS and IT curve test results of the symmetric battery prepared by the tin-modified sulfide solid electrolyte in Example 1 are shown below. Figure 2 (a) is the EIS curve of the symmetric battery prepared by the tin-modified sulfide solid electrolyte in Example 1. Figure 2 (b) is the IT polarization curve of the symmetric battery prepared by the tin-modified sulfide solid electrolyte in Example 1. Figure 2 (c) Activation energy curve of the symmetric battery prepared by the tin-modified sulfide solid electrolyte in Example 1. Figure 2 (d) is a schematic diagram of the symmetrical battery assembly of Example 1.
[0088] from Figure 2(a) It can be seen that the resistance of Example 1 is only 13.38 Ohm, which translates to a lithium-ion conductivity of 6.57 mS / cm. Furthermore, its steady-state current can be observed through the IT curve, and its electronic conductivity is further obtained as 5.81E⁻⁸ S / cm using the electronic conductivity formula. The activation energy of Example 1 is only 0.203 eV, indicating that the energy barrier that ions need to overcome for migration is very low, further confirming its high ionic conductivity.
[0089] Table 1. Lithium-ion conductivity, electronic conductivity, and activation energy of tin-modified sulfide solid electrolytes in each embodiment and comparative example.
[0090] Lithium-ion conductivity is used to characterize the ability of an electrolyte to transport lithium ions. One of the core functions of an electrolyte is to provide a migration channel for lithium ions. The higher the value, the less resistance lithium ions encounter in the electrolyte and the faster they migrate. This effectively ensures the charge and discharge efficiency and rate performance (such as fast charging capability) of electrochemical devices such as batteries. Therefore, for most electrochemical systems (such as lithium-ion batteries), the higher the lithium-ion conductivity, the better.
[0091] Electronic conductivity is used to characterize the ability of an electrolyte to transport electrons. An ideal electrolyte should only conduct ions and isolate electrons. If the electronic conductivity is too high, electrons will be ineffectively transferred in the electrolyte, which may cause self-discharge inside the battery, reduce energy conversion efficiency, and in severe cases, affect device stability. Therefore, the lower the electronic conductivity, the better.
[0092] Activation energy is used to characterize the energy barrier that lithium ions must overcome during migration in an electrolyte. When lithium ions migrate within an electrolyte, they need to overcome energy barriers formed by intermolecular forces and lattice resistance. Activation energy is a quantitative description of these barriers. The lower the activation energy, the easier it is for lithium ions to overcome the energy barrier, and the easier the migration occurs; the corresponding lithium ion conductivity is usually higher. Conversely, the higher the activation energy, the more significantly lithium ion migration is hindered, and the lower the conductivity tends to be.
[0093] As can be seen from Table 1, the lithium-ion conductivity of the tin-modified sulfide solid electrolytes prepared in Examples 1-9 is significantly greater than that of the tin-modified sulfide solid electrolytes prepared in Comparative Examples 1-5.
[0094] The electronic conductivity of the tin-modified sulfide solid electrolytes prepared in Examples 1-9 is lower than that of the tin-modified sulfide solid electrolytes prepared in Comparative Examples 1-5. The activation energies of the tin-modified sulfide solid electrolytes prepared in Examples 1-9 are also significantly lower than those of the tin-modified sulfide solid electrolytes prepared in Comparative Examples 1-5.
[0095] As shown in Table 1, the tin-modified sulfide solid electrolyte prepared by the method of this application can significantly improve its ionic conductivity, while having a small electronic conductivity and a low activation energy.
[0096] Test 3 The tin-modified sulfide solid electrolytes prepared in Examples 1-9 and Comparative Examples 1-5 were used to prepare lithium symmetric batteries.
[0097] Assembly method of lithium symmetric battery: 100 mg of tin-modified sulfide solid electrolyte powder was accurately weighed and filled into a mold cavity with an inner diameter of 10 mm. A pressure of 250 MPa was applied and held for 5-10 min until the electrolyte powder became an electrolyte sheet. Subsequently, a 10 mm diameter ultrathin lithium foil was placed on the upper and lower surfaces of the electrolyte sheet as symmetric electrodes. Then, a uniaxial pressure of 50 MPa was applied for 1 min to achieve battery structure densification and optimized electrode / electrolyte interface contact. The assembled lithium symmetric battery was connected to the Blue Electric testing system for constant current charge-discharge (CCD) testing. The results are as follows: Figure 3 As shown in Table 2. Figure 3 (a) is a CCD test curve of the lithium symmetric battery assembled in Example 1. Figure 3 (b) is the EIS curve of the lithium symmetric battery assembled in Example 1. From Figure 3 As can be observed in (a), at 3.8 mA / cm 2 The occurrence of a micro-shortage indicates that it has a high critical current density, suggesting that it has been optimized in suppressing lithium dendrite growth, which helps to further improve the cycle stability of the battery.
[0098] Table 2. Critical current densities of tin-modified sulfide solid electrolytes prepared in each example and comparative example.
[0099] When the electrolyte and electrode interface exhibits excellent compatibility, it can create a smooth and stable channel for lithium-ion transport, thereby supporting a higher critical current density: reducing transport resistance and maintaining long-term interface stability. The performance of the critical current density reflects the quality of the interface compatibility; the higher the critical current density, the better the interface compatibility between the electrolyte and electrode.
[0100] As can be seen from Table 2, the critical current density of the tin-modified sulfide solid electrolytes prepared in Examples 1-9 is greater than that of the tin-modified sulfide solid electrolytes in Comparative Examples 1-5.
[0101] Therefore, the method of this application also effectively enhances the interfacial compatibility between the tin-modified sulfide solid electrolyte and the lithium metal anode. Sn modification improves the interfacial contact between the electrolyte and the lithium metal anode, reduces interfacial resistance, and enhances interfacial stability, thereby extending the cycle life and safety performance of the all-solid-state battery.
[0102] Test 4 The tin-modified sulfide solid electrolytes prepared in Examples 1-9 and Comparative Examples 1-5 were used to prepare sulfide all-solid-state batteries (hereinafter referred to as all-solid-state batteries).
[0103] Assembly method of all-solid-state batteries: (1) Preparation of positive electrode material: VGCF (carbon fiber, a type of activated carbon), sulfide electrolyte Li6PS5Cl (particle size 2~5um) and high nickel ternary positive electrode material (NCM78) were placed in an agate mortar at a weight ratio of 5:25:70 and mixed evenly for 20 min to obtain a composite positive electrode.
[0104] (2) Assembly of the all-solid-state battery: First, 100 mg of tin-modified sulfide solid electrolyte was added to a mold with a diameter of 10 mm and pressed at 50 MPa for 10 min to form a solid electrolyte layer. Then, 10 mg of composite positive electrode was evenly spread on one side of the solid electrolyte layer and pressed at 300 MPa for 10 min to make it in close contact with the solid electrolyte layer. Finally, Li negative electrode was evenly spread on the other side of the solid electrolyte layer and pressed at 30 MPa for 1 min to complete the assembly of the all-solid-state battery.
[0105] The all-solid-state batteries prepared in Examples 1-9 and Comparative Examples 1-5 were tested, and the results are as follows: Figure 4 As shown in Tables 3 and 4. Among them, Figure 4 (a) is the first charge-discharge curve of the all-solid-state battery prepared in Example 1. Figure 4 (b) is a rate curve of the all-solid-state battery prepared in Example 1. From... Figure 4 As can be seen in (a), the all-solid-state battery assembled with the tin-modified sulfide solid electrolyte of Example 1 as the intermediate solid electrolyte layer has a first-cycle discharge specific capacity of 284.42 mAh / g and a first-cycle coulombic efficiency of 76.97%.
[0106] Table 3. First-cycle charge specific capacity, first-cycle discharge specific capacity, and first-cycle coulombic efficiency of the all-solid-state batteries prepared in Examples 1-9 and Comparative Examples 1-5.
[0107] As can be seen from Table 3, the first-cycle coulombic efficiency of the all-solid-state batteries prepared in Examples 1-9 is greater than that of the all-solid-state batteries in Comparative Examples 1-5. The first-cycle discharge specific capacity and first-cycle charge specific capacity of the all-solid-state batteries in Examples 1-9 are both greater than those of the all-solid-state batteries in Comparative Examples 1-5.
[0108] Table 3 shows significant differences in the first-cycle coulombic efficiency and first-cycle charge / discharge specific capacity among Examples 1, 8, and Comparative Examples 4-5, indicating that the Sn source doping ratio significantly affects the performance of the all-solid-state battery. A comparison of Examples 1 and Comparative Example 1 reveals that the choice of protective atmosphere also significantly impacts the performance of the all-solid-state battery. A comparison of Examples 1 and Comparative Examples 2-3 shows that the sintering temperature also significantly affects the performance of the all-solid-state battery.
[0109] Table 4 Cycle stability of all-solid-state batteries prepared in Examples 1-9 and Comparative Examples 1-5
[0110] As shown in Table 4, the tin-modified sulfide solid electrolyte materials prepared in Examples 1-9 all exhibited good cycle stability, maintaining a capacity retention of over 81% after 500 cycles of constant current charging (IC), with the highest reaching 85.6%. In contrast, the all-solid-state batteries prepared with tin-modified sulfide solid electrolytes in Comparative Examples 1-5 showed poor cycle stability, with the highest being less than 74%. This further verifies the influence of key factors in this application—Sn modification, doping ratio control, protective atmosphere selection, and high-temperature sintering temperature—on improving the cycle stability of the tin-modified sulfide solid electrolyte.
[0111] The test results show that the tin-modified sulfide solid electrolyte materials prepared in Examples 1 to 9 all exhibit good ionic conductivity and interfacial compatibility, and the cycle performance and safety performance of the all-solid-state battery are significantly improved. Among them, the tin-modified sulfide solid electrolyte material prepared in Example 1 shows the best performance in terms of ionic conductivity and interfacial compatibility, with a lithium-ion conductivity of 6.57 mS / cm. The interfacial integration between the tin-modified sulfide solid electrolyte and the lithium metal anode is greatly improved, and the charge specific capacity of the all-solid-state battery is also significantly increased. In contrast, the performance of the tin-modified sulfide solid electrolyte materials in Comparative Examples 1 to 5 is relatively poor, further verifying the importance of key factors such as Sn modification, doping ratio control, protective atmosphere selection, and high-temperature sintering temperature in improving the performance of tin-modified sulfide solid electrolytes in this application.
[0112] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this disclosure can be achieved, and this is not limited herein.
[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.
[0114] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.
Claims
1. A method for preparing a tin-modified sulfide solid electrolyte, characterized in that, The method includes: Under an inert atmosphere, Sn source and sulfide solid electrolyte are mixed at a mass ratio of 1%~10%:1 and ball-milled to obtain precursor powder; The precursor powder was sintered and cooled under a protective atmosphere to obtain a tin-modified sulfide solid electrolyte; the sintering temperature was 400~550℃ and the sintering time was 8~20h. The Sn source is one or more of metallic Sn powder and Sn sulfides; The chemical formula of the sulfide solid electrolyte is Li₂S-P₂S₅, Li₆PS₅X, where X is Cl, Br, or I. Based on the variants derived from Li₆PS₅X, Li 10 GeP2S 12 Li 10 SnP2S 12 and Li 10 SiP2S 12 One of them.
2. The preparation method according to claim 1, characterized in that, The sulfides of Sn are SnS2, SnS, and (NH4)4Sn4S. 10 Li4Sn4S 10 One or more of them.
3. The preparation method according to claim 1, characterized in that, The sintering temperature is 450~550℃.
4. The preparation method according to claim 1, characterized in that, The ball milling speed is 1000~2000 r / min, and the ball milling time is 10~60 min.
5. The preparation method according to claim 4, characterized in that, The ball milling speed is 1500~1800 r / min, and the ball milling time is 20~40 min.
6. The preparation method according to claim 1, characterized in that, The precursor powder has a particle size of 2~15μm.
7. The preparation method according to claim 1, characterized in that, The protective atmosphere is one or a mixture of argon and helium.
8. A tin-modified sulfide solid electrolyte, characterized in that, The tin-modified sulfide solid electrolyte is obtained by the preparation method described in any one of claims 1-7.
9. An all-solid-state battery, characterized in that, This includes the tin-modified sulfide solid electrolyte prepared by the preparation method according to any one of claims 1-7, or the tin-modified sulfide solid electrolyte according to claim 8.