Solid electrolyte film with high silver ion conductivity at room temperature and preparation method thereof

Abstract

The invention discloses a solid electrolyte film with high silver ion conductivity at room temperature and a preparation method thereof, the solid electrolyte film comprises the following chemical general formula: (100-x-y) GeS < 2-x > Sb < 2 > S < 3-y > AgI, x is equal to 30-73, y is equal to 28-67, and the grain gap is within 50nm. According to the preparation method, flexible regulation and control of sputtering process parameters are achieved through the double-target co-sputtering technology, so that the film keeps high silver iodide content, meanwhile, the size of grain gaps is controlled, high-speed transmission of silver ions in the film is guaranteed, the room-temperature silver ion conductivity of 5 * 10 <-4 > S / cm or above is obtained, product components are limited loosely, and the preparation method is suitable for large-scale production. And the technology universality is high.

Description

Technical Field

[0001] The present invention relates to the field of solid electrolytes, and particularly to a solid electrolyte thin film with high silver ion conductivity at room temperature and a preparation method thereof. Background Art

[0002] Solid electrolytes with high room temperature ionic conductivity have long been widely concerned. Due to their solid form, they can be better used for manufacturing miniaturized devices, and the selection of electrolyte components is more abundant.

[0003] The ionic conductivity in solid electrolytes is very important for the rapid transport of ions. Among the currently known solid electrolytes, α-silver iodide crystals have the highest ionic conductivity, but they need to be stable at temperatures above 148 °C to reach an ionic conductivity of about 1.3 S / cm. Therefore, stabilizing the α-phase of AgI with high-temperature ionic conductivity at room temperature is the goal of many current research works. Future research will further explore how to achieve higher ionic conductivity at room temperature to promote the application progress of solid electrolytes in fields such as electric vehicles and renewable energy.

[0004] Ag ion solid electrolytes can be applied to micro energy storage devices such as portable pacemaker batteries. Currently, most studies use methods such as mechanical synthesis and rapid melting quenching to prepare solid electrolytes. However, these methods often have difficulty obtaining solid electrolyte thin films with a thickness in the nanometer range and cannot be applied to fields such as flexible batteries and micro batteries that require solid electrolyte thin films. Therefore, the preparation technology for solid electrolyte thin films with high silver ion conductivity at room temperature still needs to be improved and developed. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the purpose of the present invention is to provide a solid electrolyte thin film with high silver ion conductivity at room temperature and a preparation method thereof, aiming to solve the problems of existing preparation of nanoscale thin films and low ionic conductivity at room temperature.

[0006] The technical solution of the present invention is as follows:

[0007] A solid electrolyte thin film with high silver ion conductivity at room temperature, characterized in that, in terms of molar percentage, the solid electrolyte thin film has the following chemical general formula: (100 - x - y)GeS2 - xSb2S3 - yAgI, where x = 30 - 73, y = 28 - 67, and the grain gap in the solid electrolyte thin film is within 50 nm, and the silver ion conductivity is 9.9×10 -6 ~5.3×10 -4 S / cm.

[0008] For the solid electrolyte thin film with high silver ion conductivity at room temperature, where x = 66 and y = 28.

[0009] The solid electrolyte film with high silver ion conductivity at room temperature, wherein the grain gap of the film is within 25 nm.

[0010] A method for preparing a solid electrolyte film with high silver ion conductivity at room temperature as described above, comprising:

[0011] Step A: Weigh the following raw materials according to the above ratio: elemental Ge, S, and the compound Sb2S3;

[0012] Step B: Ball-mill the weighed powders in an inert gas environment to obtain uniform GeS2-Sb2S3 powders;

[0013] Step C: Sinter the obtained GeS2-Sb2S3 powders in a vacuum environment to obtain a high-density target;

[0014] Step D: Sinter the AgI powder in a vacuum environment to obtain a high-density target;

[0015] Step E: Using the magnetron sputtering method, adjust the sputtering power of the AgI target to 6 - 16 W, and adjust the sputtering power of GeS2-Sb2S3 to 19 - 21 W, and perform co-sputtering coating to obtain a solid electrolyte film with high silver ion conductivity at room temperature.

[0016] The solid electrolyte film with high silver ion conductivity at room temperature, characterized in that in Step C, in the sintering curve, the sintering temperature reaches 250 - 350 °C, and sintering is carried out under constant temperature and pressure for 30 - 60 min at this temperature.

[0017] The solid electrolyte film with high silver ion conductivity at room temperature, characterized in that in Step D, in the sintering curve, the sintering temperature reaches 220 - 310 °C, and sintering is carried out under constant temperature and pressure for 30 - 60 min at this temperature.

[0018] The solid electrolyte film with high silver ion conductivity at room temperature, characterized in that in Step E, the sputtering gas pressure is 5 - 15 mT.

[0019] The solid electrolyte film with high silver ion conductivity at room temperature, characterized in that in Step E, co-sputtering is carried out using a dual target, the sputtering power of AgI is 4 - 18 W, and the sputtering power of GeS2-Sb2S3 is 16 - 24 W.

[0020] The solid electrolyte film with high silver ion conductivity at room temperature is characterized in that in step E, the silver ion conductivity of the solid electrolyte film is determined by the following method: at both ends of the upper surface of the solid electrolyte film, two parallel silver electrodes with a thickness of 200 nm are deposited by magnetron sputtering, and the IV curve is measured by a DC polarization method using an electrochemical workstation, and the silver ion conductivity of the solid electrolyte film is calculated according to the configuration.

[0021] Beneficial effects: The present invention provides a solid electrolyte film with high silver ion conductivity at room temperature as described above. The method of dual-target magnetron co-sputtering is used for preparation, and a solid electrolyte film with a nano-scale thickness can be obtained. There are movable silver ions inside, and the film thickness is uniform without obvious defects. Due to the high concentration of silver ions participating in charge transport and the fast transport speed, it has a high silver ion conductivity, reaching 10 -4 S / cm or more. At the same time, the present invention has loose restrictions on the product components and strong technical universality. Specific embodiments

[0022] The present invention provides a solid electrolyte film with high silver ion conductivity at room temperature and a preparation method thereof. To make the purpose, technical solution and effects of the present invention clearer and more definite, the present invention will be further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The present invention provides a solid electrolyte film with high silver ion conductivity at room temperature, which has the following chemical general formula in terms of molar percentage: (100 - x - y)GeS2 - xSb2S3 - yAgI, where x = 30 - 73, y = 28 - 67, and the silver ion conductivity of the solid electrolyte film is 9.8×10 -6 ~5.3×10 -4 S / cm. For example, when x = 66 and y = 28, the solid electrolyte film with high silver ion conductivity at high room temperature is 6GeS2 - 66Sb2S3 - 28AgI.

[0024] The grain gap of the film at room temperature has an important influence on the ionic conductivity of the solid electrolyte film. If the grain gap is too large, the transport channels of silver ions will be damaged, resulting in a low overall ionic conductivity of the film. The solid electrolyte film with high silver ion conductivity at room temperature of the present invention has a grain gap controlled within the nano-scale at room temperature, and the content of silver iodide is increased as much as possible so that the film has the characteristic of high silver ion conductivity at room temperature, up to 5.3×10 -4 S / cm, which is two orders of magnitude higher than that of a general solid electrolyte film of 10 -6 S / cm, and the present invention has loose restrictions on the product components and strong technical universality.

[0025] The present invention also provides a method for preparing a solid electrolyte film with high silver ion conductivity at room temperature as described above, including:

[0026] Step A: Weigh the following raw materials according to the above-mentioned ratio: elemental Ge, S, and the compound Sb2S3;

[0027] Step B: Place the weighed raw materials and tungsten carbide hard alloy grinding balls into a tungsten carbide hard alloy ball mill jar. The diameter of the grinding balls is preferably 10 mm, the ball-to-material ratio is 5 - 20∶1, and the filling rate of the ball mill jar is 1 / 4 - 1 / 2. Ball mill in an inert gas environment to obtain uniform GeS2 - Sb2S3 powder; preferably use planetary ball milling. Among them, the rotation speed of the planetary ball mill is 320 revolutions per minute - 800 revolutions per minute, and the ball milling time varies according to the raw material ratio, which is 50 - 100 hours. During the ball milling process, intermittent shutdown for heat dissipation is required to prevent the temperature of the abrasive from being too high, causing vitrification crystallization. For example, during the ball milling process, the ball mill runs for 5 minutes and then stops for 6 minutes.

[0028] Step C: Apply a pressure of 15.3 MPa to the GeS2 - Sb2S3 powder obtained by ball milling in a vacuum environment and sinter it using a spark plasma sintering furnace, where the sintering temperature is 250 - 350 °C and the holding time under pressure is 30 - 60 min.

[0029] Step D: Use a spark plasma sintering furnace to sinter AgI powder in a vacuum environment with a pressure of 15.3 MPa, where the sintering temperature is 220 - 310 °C and the holding time under pressure is 30 - 60 min.

[0030] Step E: Use the method of magnetron sputtering to adjust the sputtering power of the AgI target to 6 - 16 W and the sputtering power of GeS2 - Sb2S3 to 19 - 21 W, and perform dual - target co - sputtering coating to obtain a solid electrolyte film with high silver ion conductivity at room temperature. The silver ion conductivity of the film can reach 10 -4 S / cm or more.

[0031] The silver ion conductivity of the solid electrolyte film is determined by the following method: Deposit two parallel silver electrodes with a thickness of 200 nm on both ends of the upper surface of the solid electrolyte film by magnetron sputtering. Measure the IV curve by the DC polarization method using an electrochemical workstation, and calculate the silver ion conductivity of the solid electrolyte film according to the set configuration.

[0032] By adjusting the parameters of the above - mentioned magnetron sputtering, the present invention controls the grain gaps of the solid electrolyte film and the content of silver iodide therein, enabling silver ions to have better ion transport ability in the film, thereby improving the silver ion conductivity of the solid electrolyte film at room temperature.

[0033] The present invention will be described in detail below through embodiments.

[0034] Comparative Example 1 (Single-target sputtering of silver iodide)

[0035] The AgI powder was sintered using a spark plasma sintering furnace under a vacuum environment with a pressure of 15.3 MPa using the spark plasma sintering furnace. The sintering temperature was 270 °C, and the holding time under pressure was 40 min. A solid electrolyte target with a relative density of 93% was obtained.

[0036] Using the method of magnetron sputtering, the AgI sputtering power was adjusted to 16 W, the working gas pressure was 10 mT, and the sputtering time was 2 h to obtain a silver iodide thin film. The silver ion conductivity of the silver iodide thin film at room temperature was measured by the DC polarization method to be 1.0×10 -6 S / cm.

[0037] Comparative Example 2 (Single-target sputtering of solid electrolyte thin film)

[0038] The elemental Ge, S, and the compounds AgI and Sb2S3 raw materials were weighed according to the ratio of 6GeS2-66Sb2S3-28AgI. The above raw materials and tungsten carbide hard alloy grinding balls with a diameter of 10 mm were placed in a tungsten carbide hard alloy ball mill according to a ball-to-material ratio of 10:1 for planetary ball milling. The planetary ball milling parameters used were: the rotation speed was 450 revolutions per minute, and for every 5 minutes of operation, it stopped for 6 minutes, and so on in a cyclic operation. The effective ball milling time was 72 hours, and a uniform solid electrolyte powder could be obtained.

[0039] The solid electrolyte powder obtained by ball milling was sintered using a spark plasma sintering furnace under a vacuum environment with a pressure of 15.3 MPa using the spark plasma sintering furnace. The sintering temperature was 220 °C, and the holding time under pressure was 40 min. A solid electrolyte target with a relative density of 93% was obtained.

[0040] Using the method of magnetron sputtering, the sputtering power was adjusted to 16 W, the working gas pressure was 10 mT, and the sputtering time was 2 h to obtain a solid electrolyte thin film. It was found that the film had obvious cracks under scanning electron microscopy. The silver ion conductivity of the silver iodide thin film at room temperature was measured by the DC polarization method to be 6.3×10 -7 S / cm.

[0041] Example 1

[0042] Weigh the following raw materials according to the molar ratio GeS2∶Sb2S3 = 1∶11: elemental Ge, S, and the compound Sb2S3. Place the above raw materials together with tungsten carbide hard alloy grinding balls with a diameter of 10 mm into a tungsten carbide hard alloy ball mill tank according to a ball-to-material ratio of 10∶1 for planetary ball milling; the planetary ball milling parameters are: the rotation speed is 450 revolutions per minute, and it stops for 6 minutes every 5 minutes of operation. Rotate in this cycle, and the effective ball milling time is 22.75 hours to obtain a uniform GeS2-Sb2S3 powder; use a spark plasma sintering furnace to sinter the GeS2-Sb2S3 powder obtained by ball milling under a vacuum environment with a pressure of 15.3 MPa and a sintering temperature of 320 °C to obtain a target with a relative density of 93%. Use a spark plasma sintering furnace to sinter AgI powder under a vacuum environment with a pressure of 15.3 MPa and a sintering temperature of 270 °C to obtain a target with a relative density of 93%.

[0043] Using the method of co-sputtering, with a 21 W GeS2-Sb2S3 target and a 6 W AgI target, the sputtering gas pressure is 10 mT, and the sputtering time is 2 hours. A solid electrolyte film with a silver ion conductivity of 1.4×10 -5 is successfully obtained. The film has no obvious grain gaps, and its composition is 6GeS2-73Sb2S3-21AgI, which is one order of magnitude higher than that of Comparative Example 1 and two orders of magnitude higher than that of Comparative Example 2.

[0044] Example 2

[0045] Weigh the following raw materials according to the molar ratio GeS2∶Sb2S3 = 1∶11: elemental Ge, S, and the compound Sb2S3. Place the above raw materials together with tungsten carbide hard alloy grinding balls with a diameter of 10 mm into a tungsten carbide hard alloy ball mill tank according to a ball-to-material ratio of 10∶1 for planetary ball milling; the planetary ball milling parameters are: the rotation speed is 450 revolutions per minute, and it stops for 6 minutes every 5 minutes of operation. Rotate in this cycle, and the effective ball milling time is 22.75 hours to obtain a uniform GeS2-Sb2S3 powder; use a spark plasma sintering furnace to sinter the GeS2-Sb2S3 powder obtained by ball milling under a vacuum environment with a pressure of 15.3 MPa and a sintering temperature of 320 °C to obtain a target with a relative density of 93%. Use a spark plasma sintering furnace to sinter AgI powder under a vacuum environment with a pressure of 15.3 MPa and a sintering temperature of 270 °C to obtain a target with a relative density of 93%.

[0046] Using the method of co-sputtering, with a 21 W GeS2-Sb2S3 target and a 10 W AgI target, the sputtering gas pressure is 10 mT, and the sputtering time is 2 hours. A solid electrolyte film with a silver ion conductivity of 4.2×10 -4The solid electrolyte thin film has increased grain gaps in the film and a small number of pores appear, with the pore diameter within 25 nm. Its composition is 4GeS2-47Sb2S3-49AgI, which is two orders of magnitude higher than that of Comparative Example 1 and three orders of magnitude higher than that of Comparative Example 2.

[0047] Example 3

[0048] Weigh the following raw materials according to the molar ratio of GeS2∶Sb2S3 = 1∶11: elemental Ge, S, and the compound Sb2S3. Place the above raw materials together with tungsten carbide hard alloy grinding balls with a diameter of 10 mm in a tungsten carbide hard alloy ball mill according to a ball-to-material ratio of 10∶1 for planetary ball milling; the planetary ball milling parameters are: the rotation speed is 450 revolutions per minute, and it stops for 6 minutes every 5 minutes of operation. Cycle like this, and the effective ball milling time is 22.75 hours to obtain uniform GeS2-Sb2S3 powder; use the GeS2-Sb2S3 powder obtained by ball milling in a spark plasma sintering furnace, apply a pressure of 15.3 MPa in a vacuum environment, and the sintering temperature is 320 °C for sintering to obtain a target with a density of 93%. Use the AgI powder in a spark plasma sintering furnace, apply a pressure of 15.3 MPa in a vacuum environment, and the sintering temperature is 270 °C for sintering to obtain a target with a density of 93%.

[0049] Using the co-sputtering method, with a 21W GeS2-Sb2S3 target and an 8W AgI target, the sputtering gas pressure is 10 mT, and the sputtering time is 2 hours. Successfully obtain a silver ion conductivity of 5.3×10 -4 The solid electrolyte thin film has an increase in grain gaps at the nanometer level but no pores appear, and the grain gaps are within 10 nanometers. Its composition is 6GeS2-66Sb2S3-28AgI, which is two orders of magnitude higher than that of Comparative Example 1 and three orders of magnitude higher than that of Comparative Example 2.

[0050] By comparing Example 1, Example 2, Example 3 and Comparative Example 1, it can be seen that after adding the GeS2-Sb2S3 substance, the room temperature silver ion conductivity of the solid electrolyte thin film will be improved. By comparing Example 1, Example 2, Example 3 and Comparative Example 2, it can be seen that through dual-target magnetron sputtering, the composition of the thin film can be better controlled and obvious defects will not appear in the thin film, thereby improving the room temperature silver ion conductivity of the thin film. For the components of the above examples, a 21W GeS2-Sb2S3 target and an 8W AgI target can be preferably used. The co-sputtered solid electrolyte thin film has grain gaps at the nanometer level, and the room temperature silver ion conductivity can reach 5.3×10 -4 S / cm.

[0051] In summary, in the present invention, the ball-milled GeS2-Sb2S3 powder is sintered into a target, and co-sputtering of the double targets is carried out with the target sintered from AgI powder, which can better control the composition of the thin film, avoid more defects in the thin film, and have a larger operating space. Moreover, a uniform thin film with a nanoscale structure is fabricated by magnetron sputtering, solving the problem that it is difficult to prepare a nanoscale solid electrolyte thin film by the melt quenching method. By adjusting the sputtering parameters, the present invention enables the thin film to maintain a high silver iodide content while controlling the size of the grain gaps to ensure the high-speed transmission of silver ions in the thin film, so that the thin film has a high silver ion conductivity at room temperature, reaching up to 5×10 -4 S / cm or more. In addition, the present invention has loose restrictions on the product components and strong technical universality.

[0052] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for preparing a solid electrolyte thin film with high silver ion conductivity at room temperature, characterized in that, Including: Step A: Weigh the following raw materials according to the molar ratio GeS2∶Sb2S3 = 1∶11: elemental Ge, S, and the compound Sb2S3; Step B: Place the above raw materials and tungsten carbide hard alloy grinding balls with a diameter of 10 mm into a tungsten carbide hard alloy ball mill according to a ball-to-material ratio of 10∶1 for planetary ball milling; the planetary ball milling parameters are: the rotation speed is 450 revolutions per minute, every 5 minutes of operation, stop for 6 minutes, and cycle in this way. The effective ball milling time is 22.75 hours to obtain uniform GeS2-Sb2S3 powder; Step C: Use a spark plasma sintering furnace to sinter the GeS2-Sb2S3 powder obtained by ball milling under a vacuum environment with a pressure of 15.3 MPa and a sintering temperature of 320 °C to obtain a target with a relative density of 93%; Step D: Use a spark plasma sintering furnace to sinter the AgI powder under a vacuum environment with a pressure of 15.3 MPa and a sintering temperature of 270 °C to obtain a target with a relative density of 93%; Step E: Using the method of co-sputtering, with a GeS2-Sb2S3 target of 21W and an AgI target of 8W, the sputtering pressure is 10mT, and the sputtering time is 2 hours, to obtain a solid electrolyte thin film with grain gaps of the thin film less than 10nm and an ionic conductivity of silver ions of 5.3×10 -4 S / cm, and its composition is 6GeS2-66Sb2S3-28AgI.

2. A solid electrolyte thin film with high silver ion conductivity at room temperature, characterized in that In terms of molar percentage, the solid electrolyte thin film has the following chemical general formula: (100 - x - y)GeS2 - xSb2S3 - yAgI, where x = 30 - 73, y = 28 - 67, and the grain gaps of the solid electrolyte thin film are within 50 nm, and the silver ion conductivity is 9.9×10 -6 ~5.3×10 -4 S / cm.

3. The solid electrolyte film with high silver ion conductivity at room temperature according to claim 2, characterized in that, Where x = 66 and y = 28.

4. The solid electrolyte film with high silver ion conductivity at room temperature according to claim 2, characterized in that, The grain gap of the film is within 25 nm.

5. A method for preparing a solid electrolyte film with high silver ion conductivity at room temperature as described in any one of claims 2-4, characterized in that, Including: Step A: Weigh the following raw materials according to the above ratio: elemental Ge, S, and the compound Sb2S3; Step B: Ball mill the weighed powder in an inert gas environment to obtain uniform GeS2-Sb2S3 powder; Step C: Sinter the GeS2-Sb2S3 powder obtained by ball milling under a vacuum environment to obtain a high-density target; Step D: Sinter the AgI powder under a vacuum environment to obtain a high-density target; Step E: Use the method of magnetron sputtering to adjust the sputtering power of the AgI target to 6 - 16 W and adjust the sputtering power of GeS2-Sb2S3 to 19 - 21 W for co-sputtering coating to obtain a solid electrolyte film with high silver ion conductivity at room temperature.

6. The solid electrolyte film with high silver ion conductivity at room temperature according to claim 5, characterized in that, In the step C, in the sintering curve, reach the sintering temperature of 320 °C and keep the temperature and pressure constant for sintering for 30 - 60 min.

7. The solid electrolyte film with high silver ion conductivity at room temperature according to claim 5, characterized in that, In the step D, in the sintering curve, reach the sintering temperature of 270 °C and keep the temperature and pressure constant for sintering for 30 - 60 min.

8. The solid electrolyte thin film with high silver ion conductivity at room temperature according to claim 5, characterized in that, In the step E, the magnitude of the sputtering gas pressure is 5 - 15 mT.

9. The solid electrolyte thin film with high silver ion conductivity at room temperature according to claim 5, characterized in that, In the step E, use a dual target for co-sputtering, the sputtering power of AgI is 4 - 18 W, and the sputtering power of GeS2-Sb2S3 is 16 - 24 W.

10. The solid electrolyte thin film with high silver ion conductivity at room temperature according to claim 5, characterized in that, In the step E, the silver ion conductivity of the solid electrolyte film is determined by the following method: deposit two parallel silver electrodes with a thickness of 200 nm on both ends of the upper surface of the solid electrolyte film by magnetron sputtering, measure the IV curve using a DC polarization method through an electrochemical workstation, and calculate the silver ion conductivity of the solid electrolyte film according to the configuration.