Method for rapidly detecting interface structure of solid electrolyte

Abstract

The invention discloses a method for rapidly detecting an interface structure of a solid electrolyte, which comprises the following steps: taking a powder microelectrode as a working electrode, soaking the working electrode in a first electrolyte, respectively taking two pieces of metal lithium as a reference electrode and a counter electrode, and testing for 3-5 circles by cyclic voltammetry to obtain an SEI-powder microelectrode; and taking the SEI-powder microelectrode as a working electrode, soaking the working electrode in a second electrolyte containing a redox mediator probe, taking a silver wire as a reference electrode and a carbon rod as a counter electrode, carrying out cyclic voltammetry test, and obtaining SEI membrane structure information through a CV curve. By adopting the powder microelectrode, the device has the advantages of remarkably improving steady-state diffusion current, being rapid in electrochemical reaction response, small in iR drop and high in signal-to-noise ratio, and can realize accurate measurement of rapid electrochemical reaction occurring in a short time; by adopting the redox mediator probe, the interface structure of the SEI can be rapidly and nondestructively tested, and the overall property and the internal structure of the SEI can be detected.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a method for rapidly detecting the interface structure of solid electrolytes. Background Technology

[0002] During the initial charging of lithium-ion and sodium-ion batteries, the electrolyte undergoes reduction and decomposition at the negative electrode interface, forming a solid electrolyte interphase (SEI) layer. The thickness of the SEI layer typically ranges from tens to hundreds of angstroms. The SEI possesses dual properties as an ionic conductor and an electronic insulator. Its electronic insulation prevents electrons from directly transferring from the electrode into the electrolyte, avoiding interfacial side reactions and inhibiting continued electrolyte decomposition. Its ionic conductivity allows lithium ions to pass through the SEI, promoting reversible insertion / extraction of lithium ions into and out of the graphite negative electrode, which is crucial for the battery's initial efficiency and cycle stability. However, some problems arise during battery cycle charging and discharging. For example, an excessively thin SEI layer cannot effectively prevent side reactions, while an excessively thick SEI layer increases resistance, hindering lithium / sodium ion transport and affecting battery life and charge / discharge efficiency. Therefore, the stability of the SEI layer is critical to battery life and performance. Understanding the formation process and structural characteristics of the SEI layer helps improve the battery's electrochemical performance, safety, and durability.

[0003] In the study of SEI formation and testing, conventional millimeter-scale electrodes (>1 mm) have significant drawbacks compared to microelectrodes (0.1-50 μm): First, the mass transfer rate is slow. Conventional millimeter electrodes are limited by Fick's diffusion law, resulting in low diffusion flux on the large electrode surface, significant concentration polarization, and convection interference. Natural convection disrupts the diffusion layer, causing continuous drift of the steady-state current. Dominated by linear diffusion, the low mass transport rate means that reaching steady state takes several seconds to minutes, leading to distorted SEI formation kinetics. It is impossible to capture the initial nucleation process at the millisecond level, only observing the macroscopic average response, making it difficult to obtain the true steady state. Simultaneously, prolonged polarization leads to continuous electrolyte decomposition, generating "intrinsic thickened SEI" (>100 nm), masking intrinsic interface characteristics. Second, there is the current-resistance voltage drop (iR drop). Conventional millimeter electrodes require a large current to achieve the desired polarization. The large iR drop under high current distorts the true electrode potential, leading to errors in SEI formation potential measurement and failing to accurately reflect the intrinsic electrochemical behavior of the electrode system. Then there's the slow response speed. The high double-layer capacitance and slow mass transfer coupling of conventional millimeter electrodes result in an excessively large time constant, making it impossible to measure rapid electrochemical reactions occurring within a short timeframe. Finally, there's the low signal-to-noise ratio. Background noise and side-reaction interference from conventional millimeter electrodes collectively reduce the signal-to-noise ratio, thus making them suitable only for rapid electrochemical measurements. These shortcomings directly affect the accuracy and application value of SEI mechanism research.

[0004] In existing technologies, atomic force microscopy is generally used to study the surface structure of solid materials, including insulators. This method studies the surface structure of a material by detecting the extremely weak interatomic interaction forces between the surface of the sample and a micro-force-sensitive element. Specifically, a pair of extremely sensitive microcantilever arms are fixed at one end, and a tiny needle tip at the other end is brought close to the sample. The microcantilever arm will then interact with the sample, and the force will cause the microcantilever arm to deform or change its motion state. When scanning the sample, these changes are detected by a sensor to obtain information on the force distribution. Surface analysis techniques based on the interaction forces between the probe and the sample can obtain surface morphology and structure information at nanometer-level resolution by imaging subtle differences in surface height and transparent structures.

[0005] However, atomic force microscopy (AFM) testing has several drawbacks: First, it suffers from insufficient capture of overall interface information. While AFM explores nanoscale characteristics, this inevitably leads to the omission of some overall information, resulting in conclusions that cannot encompass the entire picture. Furthermore, due to the complexity of the SEI structure and composition, individual images may contain drastically different points, providing microscopic information but lacking macroscopic features. Second, it requires high sample surface uniformity. During probe descent, significant undulations in the surrounding area can affect the probe and introduce errors. However, the uniformity of some samples is difficult to meet. For example, lithium metal samples often exhibit poor uniformity due to the inhomogeneity of lithium deposition and the presence of dendrites, posing a significant challenge to AFM measurements. AFM experiments typically use planar substrates such as HOPG, magnetron sputtered copper, and etched copper. However, these substrates still have a gap with lithium, making it difficult to fully reflect the information of the lithium metal surface. Finally, probe contact can damage the surface structure. Throughout the scanning imaging process, the probe tip maintains close contact with the sample surface, and the interaction force is repulsive. During scanning, the force applied to the tip by the cantilever can potentially damage the sample's surface structure. In-situ experiments typically require the probe to be in direct contact with the sample surface, resulting in a ring electrode without a diaphragm or pressure during sample deposition. These factors inevitably alter the diffusion and mass transfer processes of lithium ions, while pressure directly affects the growth morphology of lithium. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a rapid method for detecting the interface structure of solid electrolytes (SEIs). It employs a powder microelectrode combined with cyclic voltammetry to form an SEI film, avoiding the problems of long steady-state time, large iR drop, slow response, and low signal-to-noise ratio associated with conventional electrodes. Simultaneously, it utilizes a redox-mediated probe array cyclic voltammetry method to obtain macroscopic, overall interface pore structure information of the SEI film through CV curves. This avoids the problems of insufficient overall interface information acquisition, high requirements for sample surface uniformity, and potential surface structure damage from probe contact in in-situ characterization methods such as atomic force microscopy.

[0007] To address the aforementioned technical problems, this invention provides a method for rapidly detecting the interface structure of solid electrolytes, comprising the following steps:

[0008] S1. Under a protective atmosphere, the powder microelectrode is immersed in the first electrolyte as the working electrode, and two pieces of metallic lithium are used as the reference electrode and the counter electrode, respectively. The SEI film is deposited on the powder microelectrode by cyclic voltammetry for 3-5 cycles to obtain the SEI-powder microelectrode.

[0009] S2. Under a protective atmosphere, the SEI-powder microelectrode is immersed in the second electrolyte as the working electrode, with a silver wire as the reference electrode and a carbon rod as the counter electrode, and cyclic voltammetry is performed to obtain the SEI film structure information through CV curves.

[0010] The second electrolyte includes the first electrolyte and the redox medium probe.

[0011] This invention employs powder microelectrodes to deposit an SEI film using cyclic voltammetry. After 3-5 cycles, the reduction current almost decays to zero. Since the SEI is non-conductive, the current gradually decreasing to zero indicates that the electrode surface is passivated by the SEI, thus completing the SEI preparation on the electrode. Subsequently, a redox mediator probe is added to the electrolyte. This probe is used to investigate the porous structure and channel properties of the SEI formed with different electrolytes. Smaller mediator molecules can pass through the effective diffusion channels of the SEI to reach the electrode surface and be reversibly redoxed, generating a limiting diffusion current and exhibiting a steady-state current plateau response. Larger mediator molecules cannot pass through the SEI layer, and no redox current is detected, with the current approaching zero. If a redox peak appears during the test, it indicates SEI destruction.

[0012] This invention's microelectrode possesses a unique diffusion mass transfer mechanism. Unlike the linear diffusion mode of traditional electrodes, its diffusion field exhibits a hemispherical expansion, with diffusion flux inversely proportional to the radius, increasing the mass transport rate by a hundredfold. Steady-state diffusion equilibrium is reached within milliseconds, and the current no longer decays over time. Therefore, its electrochemical response exhibits a time-independent limiting diffusion current, accurately capturing the intrinsic kinetics of interfacial reactions. Because the operating current is only in the nanoampere range, combined with the linear relationship of solution resistance voltage drop, ohmic losses are reduced to the microvolt range, resulting in minimal iR drop. This allows for ±5mV potential control accuracy in high-resistivity systems such as organic electrolytes and solid electrolytes without compensation, ensuring the accuracy of SEI formation potential measurements. Benefiting from picofarad-level double-layer capacitance, the microelectrode responds rapidly, compressing the electrode time constant to the microsecond level and eliminating charging current lag, enabling the measurement of rapid electrochemical reactions occurring within a short timeframe. Simultaneously, the high diffusion rate of the microelectrode provides a self-cleaning effect, preventing product accumulation. The reduced electrode area lowers the thermal noise current to the picofarad level, resulting in a high signal-to-noise ratio and suppressing edge-effect side reactions, making it suitable for rapid electrochemical measurements. Powder microelectrodes not only possess rapid response characteristics, but also feature large effective reaction surface area, uniform polarization, independence from conductive agents and binders, and simple preparation. They play a promoting role in characterizing electrochemical tests and optimizing preparation conditions.

[0013] This invention employs redox-mediated probes combined with cyclic voltammetry to obtain SEI film structure information via CV curves. Redox-mediated probes are molecules, polymers, ions, or compounds that can undergo reversible oxidation and reduction during electrochemical cycling. They act as electron-hole transfer agents in this process without altering the final products. Their main characteristics are reversibility and moderate redox potentials, not exceeding 3.2V (vs. Li+ / Li), preventing oxidation of the SEI layer, and not falling below 1V (vs. Li+ / Li), preventing the reduction and generation of additional SEI. When detecting the SEI interface structure and channel properties in the electrolyte, the redox-mediated probes measure the overall properties, independent of sample surface homogeneity, and do not disrupt the SEI structure.

[0014] Furthermore, in S2, obtaining SEI membrane structure information through CV curves includes:

[0015] When the CV curve shows a steady-state current plateau response, the pore size of the effective diffusion channel in the SEI film is larger than the corresponding redox medium probe size.

[0016] When the current density of the CV curve is 0, the pore size of the effective diffusion channel in the SEI film is smaller than the corresponding redox medium probe size.

[0017] Furthermore, in S2, obtaining SEI membrane structure information through CV curves includes: when a redox peak appears in the CV curve, the SEI membrane is damaged.

[0018] Further, in S2, the redox mediator probe is one of 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ), 2,3,5,6-tetramethyl-p-benzoquinone (DQ), 1,4-benzoquinone (BQ), and tetracyanoethylene (TCNE). Specifically, DBBQ has a size of [missing information]. DQ size is BQ size is TCNE size is

[0019] Furthermore, in S2, the concentration of the redox mediator probe in the second electrolyte is 1-3 mM.

[0020] Furthermore, in S1, the method for preparing the powder microelectrode is as follows: immersing the gold wire microelectrode in an acidic solution for etching treatment, causing the gold to dissolve and form a microcavity; using the etched gold wire microelectrode to grind graphite powder, so that the graphite powder fills the microcavity of the gold wire microelectrode to form a powder microelectrode.

[0021] Furthermore, in S1, the first electrolyte includes a lithium salt and an organic solvent. Preferably, it also includes a fluorinated additive. Preferably, the lithium salt is selected from one or more of LiPF6 (lithium hexafluorophosphate), LiTFSI (lithium bis(trifluoromethanesulfonate)imide), and LiFSI (lithium bis(fluorosulfonyl)imide); the organic solvent is selected from esters EC (ethylene carbonate) / DEC (diethyl carbonate) or ethers DOL (dioxopentane) / DME (ethylene glycol dimethyl ether); the fluorinated additive is selected from FEC (ethylene glycol dimethyl ether) or LiDFOB (lithium difluorooxalate borate). More preferably, the first electrolyte is: 1M LiFSI-EC / DEC, 1M LiTFSI-EC / DEC, 0.5M LiFSI-DOL / DME, 0.5M LiTFSI-DOL / DME, 1M LiPF6-EC / DEC+5% FEC, or 1M LiPF6-EC / DEC+1.5% LiDFOB, wherein the volume ratio of EC / DEC is 3:(6-8), and the volume ratio of DOL / DME is 1:(0.5-2). The structure of the SEI layer formed by different electrolytes, such as porosity and pore size, varies. The method of this invention can detect the SEI structure formed by all electrolytes.

[0022] Furthermore, in S1, the scan rate of the cyclic voltammetry test is 0.5-2 mV / s. -1 The voltage range is 0.01-3V.

[0023] Furthermore, in S2, the scan rate of the cyclic voltammetry test is 5-20 mV / s. -1 .

[0024] Furthermore, in S1 and S2, the protective atmosphere is argon or helium.

[0025] The beneficial effects of this invention are:

[0026] This invention employs a powder microelectrode combined with cyclic voltammetry to deposit an SEI film, which has the advantages of significantly improving steady-state diffusion current, rapid electrochemical reaction response, small iR drop, and high signal-to-noise ratio. It can accurately measure rapid electrochemical reactions that occur in a short time. The powder microelectrode also has the advantages of large effective reaction surface area, uniform polarization, unaffected by conductive agents and binders, and simple preparation.

[0027] This invention employs a redox mediator probe, combined with cyclic voltammetry, to rapidly and non-destructively test the interface structure of the SEI, and to detect the overall properties and internal structure of the SEI. Attached Figure Description

[0028] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is the CV curve in Embodiment 1 of the present invention;

[0030] Figure 2 This is the CV curve in Embodiment 2 of the present invention;

[0031] Figure 3 This is the CV curve in Embodiment 3 of the present invention;

[0032] Figure 4 This is the CV curve in Embodiment 4 of the present invention;

[0033] Figure 5 This is the CV curve in Embodiment 5 of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment relates to a method for preparing an SEI-powder microelectrode, comprising the following steps:

[0037] (1) Preparation of powder microelectrode: One end of a gold wire with a diameter of 50 μm is heat-sealed in a glass tube, and the other end is connected with a copper wire as a current collector and led out through a solder wire; the glass tube on one side of the gold wire is polished until the gold wire is exposed, and then the electrode end face is polished to make a gold microelectrode. Then the gold microelectrode is immersed in a solution with a volume ratio of HCl / H2O of 1:1 for etching, so that the gold dissolves to form a microcavity with a certain depth; an appropriate amount of graphite powder is placed on a smooth flat glass surface, and the graphite powder is ground with the gold microelectrode to gradually fill the microcavity to make the required powder microelectrode.

[0038] (2) SEI deposition: In a glove box filled with argon (O2 < 0.1 ppm, H2O < 0.1 ppm), 3 mL of 1 M LiPF6-EC / DEC electrolyte was added to a five-necked flask, wherein the volume ratio of EC / DEC was 3:7. Two lithium metal sheets were used as the reference electrode and the counter electrode, and the working electrode was the powder microelectrode prepared in step (1). Using a Biologic VMP3 potentiostat, cyclic voltammetry was performed at 0.5 mV s. -1 The scanning speed was tested for three cycles within a voltage range of 0.01-3V (vs. Li+ / Li) to deposit an SEI film on the powder microelectrode, thus obtaining the SEI-powder microelectrode.

[0039] The CV curves for three cycles of cyclic voltammetry in Example 1 are shown below. Figure 1 As shown, the reduction peak of the first cycle corresponds to PF in the LiPF6 salt. 6- The decomposition reaction of anions generates inorganic components such as LiF. No Li deposition or stripping peaks were observed around 0V, indicating that SEI formation preferentially precedes lithium nucleation, and no bulk lithium deposition occurred on the powder microelectrode surface. The significant decrease in current during the second cycle indicates that anions and solvent molecules in the electrolyte decomposed on the electrode surface, forming a passivation layer. Furthermore, the disappearance of the reduction peak during the second cycle suggests that anion reduction decomposition products covered the powder microelectrode surface. After the third cycle, the reduction current almost decayed to zero. Given the non-conductive nature of SEI, the gradual decrease in current to 0 indicates that the electrode surface was passivated by SEI. The preparation of SEI on the electrode was complete, and this SEI was used for subsequent experimental testing.

[0040] Example 2

[0041] This embodiment relates to a method for rapidly detecting the structure of an SEI film, including the following steps:

[0042] (1) In a glove box filled with argon (O2 < 0.1 ppm, H2O < 0.1 ppm), 3 mL of 1 M LiPF6-EC / DEC electrolyte was added to a five-necked flask, wherein the volume ratio of EC / DEC was 3:7, and 2 mM BQ was added. The reference electrode used was a silver wire, the counter electrode was a carbon rod, and the working electrode was the SEI-powder microelectrode obtained in Example 1. CV tests were performed using a Biologic VMP3 potentiostat at a scan rate of 10 mV / s. -1 The result is as follows Figure 2 As shown.

[0043] (2) For comparison, the working electrode in step (1) of this embodiment was replaced with the powder microelectrode obtained in step (1) of Example 1, and the other steps and parameters remained unchanged. CV test was performed, and the results are as follows. Figure 2 As shown.

[0044] Depend on Figure 2 It can be seen that before SEI formation, when the powder microelectrode is used as the working electrode, the CV diagram shows BQ / BQ. - The redox peaks of BQ are observed. Since the redox potential of BQ is lower than that of TCNE molecules, it ensures that BQ will not react with the SEI layer and cause SEI destruction. After SEI formation, using an SEI-powder microelectrode as the working electrode, BQ was used to test the SEI-powder microelectrode, and the reduction of BQ to form BQ2 was observed. - The limiting diffusion current was much lower than the reduction current of BQ on the powder microelectrode, and a steady-state current plateau appeared, indicating the existence of micropores in the SEI layer on the SEI-powder microelectrode surface. These SEI pores are larger than the size of BQ molecules. This allows BQ molecules to reach the electrode surface through the tiny pores in the SEI layer, thereby generating a limiting diffusion current.

[0045] Example 3

[0046] The difference between this embodiment and Embodiment 2 is that the redox mediator probe BQ in steps (1) and (2) is replaced with DBBQ, while other steps and parameters remain unchanged. CV testing is performed, and the results are as follows. Figure 3 As shown.

[0047] Depend on Figure 3 It can be seen that before the formation of the SEI, when the powder microelectrode is used as the working electrode, DBBQ exhibits good reversibility at potentials of 1.95-2.25V (vs. Li+ / Li). When the SEI-powder microelectrode is used as the working electrode, the measured current is close to 0, and there is no steady-state current plateau. This indicates that DBBQ molecules are blocked from reaching the electrode surface by the SEI due to their large size and do not reach the powder microelectrode surface through the pores in the SEI layer to be reduced. Therefore, the pore size of the SEI is smaller than that of the powder microelectrode. The absence of redox peaks in the experimental results indicates that the SEI on the powder microelectrode was not destroyed.

[0048] Example 4

[0049] The difference between this embodiment and Embodiment 2 is that the redox mediator probe BQ in steps (1) and (2) is replaced with DQ, while other steps and parameters remain unchanged. CV testing is performed, and the results are as follows. Figure 4 As shown.

[0050] Depend on Figure 4 It can be seen that the CV curve when DQ is used as the redox medium probe is similar to that in Example 3, confirming that the pore size of the SEI is smaller than that of the DQ medium probe. The absence of redox peaks in the experimental results indicates that the SEI on the powder microelectrode was not destroyed.

[0051] Example 5

[0052] The difference between this embodiment and Embodiment 2 is that the redox mediator probe BQ in steps (1) and (2) is replaced with TCNE, while other steps and parameters remain unchanged. CV testing is performed, and the results are as follows. Figure 5 As shown.

[0053] Depend on Figure 5 It can be seen that the CV curve when using TCNE as the redox medium probe is similar to that of Example 2. When using the powder electrode as the working electrode, the CV curve is similar at a potential of 2.90-3.35V (vs. Li). + TCNE exhibits excellent reversibility within the / Li range. When the SEI-powder electrode is used as the working electrode, a steady-state current plateau similar to that of BQ molecules appears, indicating that both TCNE and BQ molecules, with their small molecular size, reach the surface of the powder microelectrode through the pores of the SEI layer, are reduced on the electrode surface, and generate a limiting diffusion current.

[0054] Examples 2-5 show that the redox mediator probe exhibits reversible redox peaks only on the surface of the powder microelectrode. When using the redox mediator probe to detect SEI-powder microelectrodes, DBBQ and DQ molecules are too large to pass through the pores of the SEI and reach the electrode surface for reduction, resulting in curves with current densities close to 0. Smaller TCNE and BQ molecules can pass through the sub-nanometer pores of the SEI and be reduced on the powder microelectrode surface, exhibiting a steady-state current response. The size of the redox mediator probe is DBBQ > DQ > BQ > TCNE; therefore, the effective diffusion channel pore size of the SEI layer is between that of the BQ molecule. With DQ molecules between.

[0055] In summary, this invention employs a powder microelectrode combined with cyclic voltammetry to deposit an SEI film, which has the advantages of significantly improving steady-state diffusion current, rapid electrochemical reaction response, small iR drop, and high signal-to-noise ratio, enabling accurate measurement of rapid electrochemical reactions occurring within a short time. The powder microelectrode also has advantages such as a large effective reaction surface area, uniform polarization, independence from conductive agents and binders, and simple preparation. By using a redox medium probe combined with cyclic voltammetry, the interface structure of the SEI can be tested rapidly and non-destructively, and the overall properties and internal structure of the SEI can be probed.

[0056] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for rapidly detecting the interface structure of solid electrolytes, characterized in that, Includes the following steps: S1. Under a protective atmosphere, the powder microelectrode is immersed in the first electrolyte as the working electrode, and two pieces of metallic lithium are used as the reference electrode and the counter electrode, respectively. The SEI film is deposited on the powder microelectrode by cyclic voltammetry for 3-5 cycles to obtain the SEI-powder microelectrode. S2. Under a protective atmosphere, the SEI-powder microelectrode is immersed in the second electrolyte as the working electrode, with a silver wire as the reference electrode and a carbon rod as the counter electrode, and cyclic voltammetry is performed to obtain the SEI film structure information through CV curves. The second electrolyte includes the first electrolyte and the redox medium probe.

2. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S2, the SEI membrane structure information obtained through CV curves includes: When the CV curve shows a steady-state current plateau response, the pore size of the effective diffusion channel in the SEI film is larger than the corresponding redox medium probe size. When the current density of the CV curve is 0, the pore size of the effective diffusion channel in the SEI film is smaller than the corresponding redox medium probe size.

3. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S2, the SEI membrane structure information obtained through the CV curve includes: when a redox peak appears in the CV curve, the SEI membrane is damaged.

4. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S2, the redox mediator probe is one of 2,5-di-tert-butyl-1,4-benzoquinone, 2,3,5,6-tetramethyl-p-benzoquinone, 1,4-benzoquinone, and tetracyanoethylene.

5. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S2, the concentration of the redox mediator probe in the second electrolyte is 1-3 mM.

6. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S1, the method for preparing the powder microelectrode is as follows: immersing the gold wire microelectrode in an acidic solution for etching treatment, causing the gold to dissolve and form a microcavity; using the etched gold wire microelectrode to grind graphite powder, so that the graphite powder fills the microcavity of the gold wire microelectrode to form a powder microelectrode.

7. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S1, the first electrolyte includes lithium salt and organic solvent.

8. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S1, the scan rate of the cyclic voltammetry test is 0.5-2 mV / s. -1 The voltage range is 0.01-3V.

9. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S2, the scan rate of the cyclic voltammetry test is 5-20 mV / s. -1 .

10. The method for rapid detection of solid electrolyte interface structure as described in claim 1, characterized in that, In S1 and S2, the protective atmosphere is argon or helium.

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