A method of electrothermally pulsing regeneration of damaged oxide solid state electrolyte
By using Joule heating substrate segmented sintering technology, the structural damage and performance degradation problems of oxide solid electrolytes have been solved, enabling efficient regeneration and resource recovery, and improving the quality and service life of the electrolyte.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2024-12-16
- Publication Date
- 2026-05-15
AI Technical Summary
Oxide solid electrolytes are susceptible to lithium dendrite growth, leading to structural damage and performance degradation. Frequent replacement results in high costs, and rare earth elements with recycling value cannot be effectively recycled and reused.
Joule heating is used to generate Joule heat by passing an electric current through a Joule heating substrate to sinter damaged oxide solid electrolytes in stages, remove impurities and densify them, thereby improving the quality of the electrolyte.
It significantly shortens regeneration time, reduces lithium-ion volatilization, improves electrolyte conductivity and mechanical strength, extends service life, and reduces costs.
Smart Images
Figure CN119683592B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery material resource recycling technology, and relates to a method for regenerating damaged oxide solid electrolytes by electrothermal pulse. Background Technology
[0002] Solid electrolytes can be classified into three types based on the electrolyte type: oxide, sulfide, and polymer. Among them, oxide solid electrolytes have high lithium-ion conductivity (10⁻⁶ ppm). -3 -10 -4 With its high strength (S / cm), high mechanical strength, low interfacial resistance, and good chemical stability, oxide solid-state electrolyte (OSE) is a strong candidate for next-generation electrolyte materials. However, OSEs are susceptible to short circuits caused by lithium dendrite growth, leading to structural damage, performance degradation, and ultimately OSE failure. This necessitates replacement with new OSEs, which increases operating costs and hinders practical applications. Furthermore, damaged OSEs often contain rare earth elements (such as lanthanum and hafnium) and rare elements (such as zirconium, tantalum, niobium, and scandium), which have high recycling value. These elements can be recovered during OSE regeneration, enabling resource recycling and reuse. Therefore, regenerating damaged OSEs is of great significance.
[0003] The quality of the regenerated oxide solid electrolyte directly affects its recycling duration and number of cycles. The better the quality of the regenerated oxide solid electrolyte, the longer its recycling time and the more beneficial it is for practical applications.
[0004] Therefore, it is necessary to provide a method for regenerating damaged oxide solid electrolytes by electrothermal pulses, thereby improving the regeneration quality of damaged oxide solid electrolytes and making fuller use of oxide solid electrolytes. Summary of the Invention
[0005] To address the problems in the background art, this invention utilizes Joule heating to generate Joule heat on a Joule-heated substrate for sintering repair of damaged oxide solid electrolytes. This significantly shortens the time required for regeneration of damaged oxide solid electrolytes, improves regeneration efficiency, rapidly removes impurities, and significantly reduces lithium-ion volatilization. Consequently, it effectively mitigates the quality degradation caused by the oxide solid electrolyte regeneration process, resulting in a high-quality regenerated oxide solid electrolyte.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:
[0007] The method specifically involves placing the damaged oxide solid electrolyte between Joule heating substrates, applying electricity to the Joule heating substrates, and generating Joule heat to sinter the damaged oxide solid electrolyte in segments. After sintering, a regenerated oxide solid electrolyte is obtained.
[0008] Preferably, the segmented sintering is performed in two stages, with the first stage having a heating rate of 10⁻¹⁰. 5 The sintering temperature is 300-800℃, and the holding time is 5-600s; the heating rate for the second stage of sintering is 10℃ / s. 2 -10 5 ℃ / s, sintering temperature is 900-2000℃, and the holding time is 1-300s.
[0009] Preferably, the segmented sintering is carried out in an atmosphere of air, oxygen, argon, or a vacuum environment.
[0010] Preferably, during the sintering process, a pressure of 0-10T is applied to the damaged oxide solid electrolyte.
[0011] Preferably, the Joule heating substrate is one of a carbon substrate, a molybdenum substrate, or a tungsten substrate.
[0012] Preferably, the carbon substrate includes one of carbon cloth, carbon felt, and carbon fiber; the molybdenum substrate is a molybdenum sheet; and the tungsten substrate is a tungsten sheet.
[0013] Preferably, the oxide solid electrolyte is one of NASICON type oxide solid electrolyte, garnet type oxide solid electrolyte, or perovskite type oxide solid electrolyte.
[0014] Preferably, the NASICON-type oxide solid electrolyte has the general chemical formula Li. 1+x Al x Z 2-x (PO4)3, where Z is one or more of Ti, Ge, and Zr, x is the number of atoms, 0 ≤ x ≤ 0.4; the chemical formula of the garnet-type oxide solid electrolyte is Li. 7-x La3Zr 2-x A x O 12 Wherein, A is one or more of the elements Ta, Nb, Sn, Hf, Sc, and Ge, and 0 ≤ x ≤ 0.75; the chemical formula of the perovskite oxide solid electrolyte is Li 3x La 0.66-x TiO3, where 0 <x≤0.16。
[0015] Preferably, the damaged oxide solid electrolyte has a diameter of 5-50 mm and a thickness of 0.5-10 mm.
[0016] The beneficial effects of this invention are:
[0017] 1. This invention uses Joule heating to generate Joule heat on a Joule-heated substrate to sinter and repair damaged oxide solid electrolytes. The entire repair and regeneration process can be controlled within 10 minutes, resulting in extremely high repair and regeneration efficiency for damaged oxide solid electrolytes.
[0018] 2. Lithium ions are an essential component of oxide solid electrolytes. The lithium ion content in oxide solid electrolytes directly affects their performance. During the repair and regeneration process of damaged oxide solid electrolytes, they need to be heated to a high temperature. Lithium ions will volatilize when heated. The longer the heating time, the more lithium ions volatilize, and the more the quality of the regenerated oxide solid electrolyte decreases. This invention can complete the entire repair and regeneration process in a very short time, effectively reducing the amount of lithium ion volatilization, thereby improving the quality of the regenerated oxide solid electrolyte.
[0019] 3. The present invention removes volatile impurities such as organic matter from the surface of the damaged oxide electrolyte through the first stage of sintering, and promotes the densification of the damaged oxide solid electrolyte through the second stage of sintering, ultimately obtaining an oxide solid electrolyte with uniform grain size, complete structure, and high conductivity and mechanical strength, which makes it have high stability and cycle performance in practical applications.
[0020] 4. The oxide solid electrolyte repaired and regenerated by the method of the present invention has high quality, can effectively extend its service life, and can increase the number of repair and regeneration cycles of oxide solid electrolyte, thereby improving the utilization rate of oxide solid electrolyte and reducing the application cost of oxide solid electrolyte.
[0021] 5. The method of the present invention is simple, easy to operate, easy to control, and has a low overall repair and regeneration cost, making it suitable for industrial application. Attached Figure Description
[0022] Figure 1 The images show the original state, damaged state, and regenerated state of the oxide solid electrolyte in Example 1 of the present invention, where (a) is the original state image, (b) is the damaged state image, and (c) is the regenerated state image.
[0023] Figure 2 The images shown are scanning electron microscope (SEM) images of the damaged state and the regenerated state of the oxide solid electrolyte in Example 1 of the present invention, where (a) is the SEM image of the damaged state, (b) is the SEM image of the regenerated state, (c) is a partial enlarged view of (a), and (d) is a partial enlarged view of (b).
[0024] Figure 3The image shows the X-ray diffraction (XRD) pattern of the damaged oxide solid electrolyte and its regeneration in Example 1 of this invention.
[0025] Figure 4 The diagram shows the room temperature impedance (EIS) of the oxide solid electrolyte in its original state and after regeneration in Example 1 of this invention.
[0026] Figure 5 The images shown are scanning electron microscope (SEM) images of the oxygen solid electrolyte in the damaged state and after regeneration in Example 3 of the present invention, where (a) is the SEM image of the damaged state and (b) is the SEM image of the regenerated state.
[0027] Figure 6 The image shows the X-ray diffraction (XRD) pattern of the oxide solid electrolyte after regeneration in Comparative Example 1 of this invention.
[0028] Figure 7 This is a scanning electron microscope (SEM) image of the oxide solid electrolyte after regeneration in Comparative Example 1 of the present invention.
[0029] Figure 8 The image shows the room temperature impedance (EIS) diagram of the oxide solid electrolyte after regeneration in Comparative Example 1 of this invention.
[0030] Figure 9 This is a schematic diagram of the method flow of the present invention. Detailed Implementation
[0031] The present invention will be further described in detail below with reference to specific embodiments.
[0032] Example 1
[0033] This embodiment repairs and regenerates damaged oxide solid electrolytes using the following method:
[0034] Damaged lithium aluminum titanium phosphorus oxide solid electrolyte Li 1.4 Al 0.4 Ti 1.6 (PO4)3 (LATP) is placed at the center between two identical rectangular carbon felts, completely encasing the LATP. A pressure of 5T is applied to the LATP. In an air atmosphere, an electric current is passed through the carbon felts, causing Joule heating. The damaged LATP electrolyte is then hot-pressed and sintered in stages. By adjusting the current, the carbon felts are heated to 300℃ at a rate of 10℃ / s for the first stage of LATP sintering. After holding at this temperature for 600s, the current is adjusted again to allow the carbon felts to heat up at a rate of 10℃ / s. 2 The LATP was heated to 900℃ at a heating rate of ℃ / s for a second stage of sintering, and held for 300s. After sintering, regenerated LATP sheets were obtained.
[0035] Take pictures of the regenerated LATP film, such as Figure 1 As shown in (c), SEM experiments were performed on the regenerated LATP, and the results are as follows. Figure 2 As shown, XRD experiments were performed on the regenerated LATP tablets, and the results are as follows. Figure 3 As shown, the room temperature impedance of the regenerated LATP sheet was tested, and the results are as follows. Figure 4 As shown.
[0036] pass Figure 1 A comparison of (a, b, c) shows that the surfaces of the original LATP sheet and the regenerated LATP sheet are clean, while the damaged LATP sheet shows black patches. These are organic impurities, lithium dendrites and their derivatives generated during the use of LATP. This indicates that after repair and regeneration using the method of this invention, the organic matter on the LATP surface volatilizes, and the lithium dendrites and their derivatives in the grain boundaries react in situ as sintering aids. As a result, the regenerated LATP sheet is free of black patches. The lithium dendrites and their derivatives in the grain boundaries, as sintering aids, can effectively fill the voids and microcracks in the oxide solid electrolyte, making the electrolyte grain size more uniform, improving the integrity of the electrolyte structure, thereby increasing the ionic conductivity and mechanical strength of the electrolyte, and enhancing its stability and cycle performance.
[0037] pass Figure 2 (b) and (c) show that after the damaged LATP sheet is repaired and regenerated, its black patch material (organic impurities, lithium dendrites and their derivatives) is assimilated by the surrounding LATP grains and regenerated into uniform and dense grains.
[0038] pass Figure 3 It can be seen that the XRD pattern of the regenerated LATP tablet corresponds completely with the standard PDF pattern of LATP, indicating that the repair and regeneration method of the present invention does not change the crystal structure of the oxide solid electrolyte. Therefore, after repair and regeneration by the method of the present invention, the oxide solid electrolyte can be used normally.
[0039] Combination Figure 4 After fitting and calculation based on the impedance data, the room temperature ionic conductivity of the original LATP tablet was found to be 1.08 × 10⁻⁶. -4 The room temperature ionic conductivity of the regenerated LATP sheet is 3.19 × 10⁻⁶ S / cm. -4The significantly improved room-temperature ionic conductivity (S / cm) of the regenerated LATP sheet demonstrates two key aspects. First, the extremely short regeneration process of this invention avoids lithium volatilization, thus preserving the quality of the oxide solid electrolyte. Second, it proves that lithium dendrites and their derivatives can act as sintering aids during the regeneration process, increasing the lithium ion concentration in LATP while eliminating them, thereby raising the ionic conductivity of the regenerated LATP sheet. This also proves the high quality of the regenerated oxide solid electrolyte obtained through this method. Compared to the original LATP, the increased ionic conductivity of the regenerated LATP sheet is primarily due to the introduction of non-conductive lithium during normal use caused by the formation of lithium dendrites and their derivatives. Although these lithium dendrites and their derivatives increase the amount of lithium, they cannot provide effective ionic conduction and instead cause structural damage to the oxide solid electrolyte, leading to a decline in electrolyte performance. After the damaged oxide solid electrolyte is repaired and regenerated by the method of the present invention, not only can these useless lithium dendrites and their derivatives be removed or transformed, thereby restoring the ion conduction channel, but the concentration of usable lithium ions in LATP can also be increased, ultimately making the ionic conductivity of the repaired and regenerated oxide solid electrolyte better than that of the original electrolyte.
[0040] Example 2
[0041] This embodiment repairs and regenerates damaged oxide solid electrolytes using the following method:
[0042] Damaged lithium aluminum titanium phosphorus oxide solid electrolyte Li 1.4 Al 0.4 Ti 1.6 (PO4)3(LATP) is placed at the center between two identical rectangular molybdenum sheets, completely encapsulating the LATP. No pressure is applied to the LATP. In an argon atmosphere, an electric current is passed through the molybdenum sheets, causing them to generate Joule heat. The damaged LATP electrolyte is then hot-pressed and sintered in segments. By controlling the current, the molybdenum sheets are sintered at 10°C. 3 The LATP was heated to 600℃ at a heating rate of ℃ / s for the first stage of sintering. After holding at this temperature for 20 seconds, the current was adjusted again to allow the carbon felt to heat up at a rate of 10℃ / s. 4 The LATP was heated to 1000℃ at a heating rate of ℃ / s for a second stage of sintering, and held for 5s. After sintering, regenerated LATP sheets were obtained.
[0043] The regenerated LATP tablets obtained in this embodiment have similar performance to the regenerated LATP tablets in Example 1.
[0044] Example 3
[0045] This embodiment repairs and regenerates damaged oxide solid electrolytes using the following method:
[0046] Damaged lithium lanthanum zirconium tantalum oxide solid electrolyte Li 6.4 La3Zr 1.4 Ta 0.6 O 12 (LLZTO) is placed at the center between two rectangular tungsten sheets of the same size, so that the LLZTO is completely wrapped by the tungsten sheets. A pressure of 10T is applied to the LLZTO at 1.0×10⁻⁶. 3 Under vacuum conditions, an electric current is applied to a tungsten sheet, causing it to generate Joule heat. This heat is then used to hot-press and sinter the damaged LLZTO electrolyte in segments. By controlling the current, the molybdenum sheet is heated to 10 kJ / m². 5 The LLZTO was heated to 800℃ at a heating rate of ℃ / s for the first stage of sintering. After holding at that temperature for 5 seconds, the current was adjusted again to allow the carbon felt to heat up at a rate of 10℃ / s. 5 The LLZTO was heated to 2000℃ at a heating rate of ℃ / s for a second stage of sintering, and the holding time was 1s. After sintering, regenerated LLZTO sheets were obtained.
[0047] SEM experiments were performed on the regenerated LLZTO tablets, and the results are as follows: Figure 5 As shown in (b).
[0048] pass Figure 5 (a) It can be seen that bubbly lithium dendrites and their oxides appeared in the damaged LLZTO wafer. After repair and regeneration by the method of the present invention, the bubbles in the LLZTO wafer were assimilated by the surrounding LLZTO grains and regenerated into uniform and dense cubic neo-Argan LLZTO grains (e.g. Figure 5 (b) shown).
[0049] Comparative Example
[0050] In this comparative example, the damaged LATP was sintered in a muffle furnace. The damaged LATP used in this comparative example was the same as that in Example 1. The specific sintering process in this comparative example was as follows: the damaged LATP was placed in a muffle furnace, the heating rate was set to 3°C / min, the temperature of the muffle furnace was raised to 900°C, and then held for 5 hours. Then the LATP was cooled to room temperature with the furnace to obtain regenerated LATP sheets.
[0051] XRD experiments were performed on the comparative regenerated LATP tablets, and the results are as follows: Figure 6 As shown, SEM experiments were performed on the regenerated LATP tablets, and the results are as follows. Figure 7 As shown, the room temperature impedance of the regenerated LATP sheet was tested, and the results are as follows. Figure 8 As shown.
[0052] pass Figure 6As can be seen, the XRD results of the LATP tablets in this comparative example, compared with the standard card, show the formation of TiO2 and Li3PO4 impurity phases.
[0053] pass Figure 7 It can be seen that the regenerated LATP tablets in this comparative example have many pores and cracks, and poor density, indicating that the quality of the regenerated LATP tablets in this comparative example is poor.
[0054] Combination Figure 8 The data, after fitting and calculation, yielded a room temperature ionic conductivity of 4.38 × 10⁻⁶ for the regenerated LATP tablets in this comparative study. -5 The S / cm of the regenerated LATP at room temperature was significantly lower than that of the original LATP, further demonstrating that the quality of the regenerated LATP tablets in this comparative study was poor.
[0055] In summary, the method of this invention can efficiently repair damaged oxide solid electrolytes, effectively improve the quality of the repaired and regenerated oxide solid electrolytes, enable the oxide solid electrolytes to be used continuously for a long time, and increase the number of repair and regeneration cycles of oxide solid electrolytes, thus laying an excellent foundation for the practical application of oxide solid electrolytes.
[0056] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.
Claims
1. A method for regenerating damaged oxide solid electrolytes via electrothermal pulses, characterized in that: The method specifically involves placing the damaged oxide solid electrolyte between Joule heating substrates, applying electricity to the Joule heating substrates, and generating Joule heat on the Joule heating substrates to sinter the damaged oxide solid electrolyte in segments. After sintering, a regenerated oxide solid electrolyte is obtained. During the sintering process, a pressure greater than 0T and not exceeding 10T is applied to the damaged oxide solid electrolyte. The segmented sintering is divided into two stages, with the first stage sintering heating rate being 10⁻¹⁰. 5 The sintering temperature is 300-800℃, and the holding time is 5-600s; the heating rate for the second stage of sintering is 10℃ / s. 2 -10 5 ℃ / s, sintering temperature is 900-2000℃, and the holding time is 1-300s.
2. The method for regenerating damaged oxide solid electrolytes by electrothermal pulse according to claim 1, characterized in that: The segmented sintering is carried out in an atmosphere of air, oxygen, or argon, or in a vacuum environment.
3. The method for regenerating damaged oxide solid electrolytes by electrothermal pulse according to claim 1, characterized in that: The Joule heating substrate is one of a carbon substrate, a molybdenum substrate, or a tungsten substrate.
4. The method for regenerating damaged oxide solid electrolytes by electrothermal pulse according to claim 3, characterized in that: The carbon substrate includes one of carbon cloth, carbon felt, and carbon fiber; the molybdenum substrate is a molybdenum sheet; and the tungsten substrate is a tungsten sheet.
5. The method for regenerating damaged oxide solid electrolytes by electrothermal pulse according to claim 1, characterized in that: The oxide solid electrolyte is one of the following: NASICON type oxide solid electrolyte, garnet type oxide solid electrolyte, and perovskite type oxide solid electrolyte.
6. The method for regenerating damaged oxide solid electrolytes by electrothermal pulse according to claim 5, characterized in that: The general chemical formula of the NASICON-type oxide solid electrolyte is Li 1+x Al x Z 2-x (PO4)3, where Z is one or more of Ti, Ge, and Zr, x is the number of atoms, 0 ≤ x ≤ 0.4; the chemical formula of the garnet-type oxide solid electrolyte is Li. 7-x La3Zr 2-x A x O 12 Wherein, A is one or more of the elements Ta, Nb, Sn, Hf, Sc, and Ge, and 0 ≤ x ≤ 0.75; the chemical formula of the perovskite oxide solid electrolyte is Li 3x La 0.66-x TiO3, where 0 <x≤0.16。 7. The method for regenerating damaged oxide solid electrolytes by electrothermal pulse according to claim 1, characterized in that: The damaged oxide solid electrolyte has a diameter of 5-50 mm and a thickness of 0.5-10 mm.