A method for visualizing detection of lithium ion transport paths in a composite solid-state electrolyte

Abstract

This invention belongs to the field of composite solid electrolytes and advanced characterization technology, and discloses a method for visually detecting lithium-ion transport pathways in composite solid electrolytes, including... 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing... 6 Li + A vertical cross-section sample in the direction of permeation, containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map 7 Li + Distribution maps and feature element distribution maps, for 6 Li + Distribution map 7 Li + The distribution map and characteristic element distribution map are used to detect the transport path of lithium ions in the composite solid electrolyte. This invention can realize the direct visualization of the lithium ion transport path in the composite solid electrolyte, and transform the abstract transport mechanism into an intuitive transport path image.

Description

Technical Field

[0001] This invention relates to the field of composite solid electrolytes and advanced characterization technology, specifically to a method for visually detecting lithium-ion transport pathways in composite solid electrolytes. Background Technology

[0002] Composite solid electrolytes are composed of several materials (such as polymers combined with fast ion conductors such as lithium lanthanum zirconium oxide and lithium lanthanum titanium oxide). They are designed to combine the advantages of each component and take into account high ionic conductivity, good mechanical properties and interfacial contact performance. They are the core materials for the next generation of high-safety and high-energy-density solid-state batteries.

[0003] The lithium-ion transport mechanism of composite solid electrolytes is extremely complex and is generally considered to be a coupling of two mechanisms: first, bulk transport of lithium ions in a continuous phase (such as a polymer phase or a ceramic phase); second, transport of lithium ions along the interface between the two phases.

[0004] However, existing methods for detecting lithium-ion transport pathways mainly fall into four categories: macroscopic performance testing (such as total conductivity testing), model prediction, traditional characterization techniques, and solid-state NMR. Among these, macroscopic performance testing and model prediction cannot provide microscopic information about lithium-ion transport pathways with spatial resolution; traditional characterization techniques also have limitations—scanning electron microscopy cannot distinguish lithium elements, transmission electron microscopy has low sensitivity to lithium elements, and the sample preparation process is complex and the samples are easily damaged; solid-state NMR is difficult to achieve visual resolution.

[0005] Therefore, there is an urgent need for a new technology that can solve the problem of the inability to visualize and distinguish ion transport paths. Summary of the Invention

[0006] The purpose of this invention is to provide a visualization detection method for lithium-ion transport paths in composite solid electrolytes, so as to overcome the problems existing in the prior art. This invention can realize the direct visualization of lithium-ion transport paths in composite solid electrolytes, and transform the abstract transport mechanism into an intuitive transport path image.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] This invention provides a method for visually detecting lithium-ion transport pathways in composite solid electrolytes, comprising the following steps:

[0009] Step 1, perform the composite solid electrolyte treatment. 6 Li isotope selective labeling;

[0010] Step 2, for 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing...6 Li + A sample with a vertical cross-section along the permeation direction;

[0011] Step 3, for those containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map 7 Li + Distribution map and feature element distribution map;

[0012] Step 4, for 6 Li + Distribution map 7 Li + The distribution map and characteristic element distribution map are used to detect the transport path of lithium ions in the composite solid electrolyte.

[0013] In some embodiments, the composite solid electrolyte comprises a polymer matrix, an inorganic lithium-ion conductor material distributed in the polymer matrix, and a component containing... 7 Li + The lithium salt; wherein the polymer matrix includes a polymer matrix phase, and the inorganic lithium-ion conductor material includes an inorganic lithium-ion conductor material phase.

[0014] In some embodiments, the feature element distribution map includes a feature element distribution map for spatially locating a polymer matrix and a feature element distribution map for spatially locating an inorganic lithium-ion conductor material.

[0015] Among them, the characteristic element of the polymer matrix used for spatial positioning is carbon, and the characteristic element of the inorganic lithium-ion conductor material used for spatial positioning is the metal element or ion group in the inorganic lithium-ion conductor material.

[0016] In some embodiments, the composite solid electrolyte is a PEO-LiTFSI / LLZO composite solid electrolyte membrane or a PEO-LiTFSI / LLTO composite solid electrolyte membrane.

[0017] In some embodiments, the above 6 Li + Distribution map 7 Li + The distribution maps and characteristic element distribution maps were used to detect the transport paths of lithium ions in the composite solid electrolyte, specifically including:

[0018] Will 6 Li + Distribution map and 7 Li + The distribution maps are overlaid to... 6 Li+ Spatial overlay and correlation analysis were performed between the distribution map and the feature element distribution map;

[0019] like 6 Li + If the lithium ions are concentrated within the inorganic lithium-ion conductor material phase, then the transport path of lithium ions is a bulk transport mechanism.

[0020] like 6 Li + If the lithium ions are concentrated at the interface between the inorganic lithium-ion conductor material phase and the polymer matrix phase and extend along the interface, then the lithium-ion transport path is the interfacial transport mechanism.

[0021] In some embodiments, the process of performing the composite solid electrolyte 6 Li isotope selective labeling, specifically including:

[0022] use 6 Li metal is used as the anode, and a symmetrical cell is assembled with a composite solid electrolyte. The surface of the composite solid electrolyte opposite to the anode is used as a marking surface. A constant current is applied to the symmetrical cell for polarization, thus completing the process. 6 Li isotope selective labeling.

[0023] In some embodiments, the current density of the constant current is 0.1–0.5 mA / cm². 2 The polarization time is 20–40 min.

[0024] In some embodiments, the rapid physical method includes liquid nitrogen quenching; the in-situ sectioning method includes focused ion beam cutting.

[0025] In some embodiments, the pair containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, specifically including:

[0026] Using a single ion beam scan includes 6 Li + A sample with a vertical cross-section along the permeation direction.

[0027] In some embodiments, the secondary ion mass spectrometry analysis employs a time-of-flight secondary ion mass spectrometer or a nanosecondary ion mass spectrometer.

[0028] The primary ion beam includes O2 + Cs + Or liquid metal ion beam.

[0029] The above technical solution has the following advantages or beneficial effects:

[0030] This invention provides a method for visually detecting lithium-ion transport paths in composite solid electrolytes, achieving for the first time direct visualization of lithium-ion transport paths in composite solid electrolytes, transforming abstract transport mechanisms into intuitive transport path images; through 6 The combination of Li isotope selective labeling and secondary ion mass spectrometry analysis can effectively distinguish 6 Li + Distribution map and 7 Li + The distribution map significantly improved the signal-to-noise ratio and the clarity of the conclusions; through the analysis of... 6 Li + Distribution map 7 Li + By detecting the distribution map and the characteristic element distribution map, the transport path of lithium ions in the composite solid electrolyte can be obtained, thus providing key and direct experimental basis for the precise optimization of material formulation and significantly accelerating the development process of composite solid electrolytes.

[0031] In some embodiments, by specifying the type of composite solid electrolyte, it is ensured that during the process... 6 Li isotope selective labeling and secondary ion mass spectrometry analysis 6 Li + and 7 Li + The source is clearly distinguishable, thus enabling dynamic transport of lithium (…). 6 Li + ) and static electrolyte lithium ( 7 Li + The high-contrast separation is the basis for this method to obtain high signal-to-noise ratio and high-reliability visual detection results.

[0032] In some embodiments, by setting carbon as the characteristic element for spatial positioning of the polymer matrix, and using metal elements or ion groups to clarify the position of the inorganic lithium-ion conductor material, the lithium-ion transport path and interface distribution characteristics are presented intuitively, providing key visualization basis for optimizing the structure and ion conduction efficiency of composite solid electrolytes.

[0033] In some embodiments, by employing a PEO-LiTFSI / LLZO composite solid electrolyte membrane or a PEO-LiTFSI / LLTO composite solid electrolyte membrane, the three-dimensional ion channel network between the polymer matrix and the inorganic lithium-ion conductor material can be clearly presented, achieving high-resolution visualization of the lithium-ion transport path.

[0034] In some embodiments, by 6 Li + Distribution map and 7 Li + Overlaying distribution maps6 Li + By spatially superimposing and correlating the distribution maps with the characteristic element distribution maps, the bulk transport mechanism and the interfacial transport mechanism can be clearly distinguished, and the actual transport path of lithium ions between the polymer matrix and the inorganic lithium ion conductor material can be intuitively displayed.

[0035] In some embodiments, by using the surface of the composite solid electrolyte opposite to the anode as a marker surface, a constant current is applied to the symmetrical cell for polarization, which can provide a basis for imaging the subsequent ion transport path of the target area without damaging the material structure.

[0036] In some embodiments, the current density of the constant current is controlled between 0.1 and 0.5 mA / cm². 2 The polarization time is limited to 20–40 minutes to ensure that 6 Li isotopes can be fully and uniformly embedded in the near-marked area of ​​the composite solid electrolyte, while avoiding problems such as structural damage to the composite solid electrolyte, aggravated interfacial side reactions, or lithium dendrite growth that may be caused by excessive current density or excessive time, thus ensuring the authenticity and accuracy of subsequent detection results.

[0037] In some embodiments, liquid nitrogen quenching can rapidly fix the transient structural state and lithium-ion distribution of the composite solid electrolyte, effectively suppressing ion migration and relaxation; combined with focused ion beam cutting to include 6 Li + The preparation of samples with vertical cross-sections in the permeation direction can preserve the original interface morphology to the greatest extent and expose the true internal structure, providing a undisturbed basis for subsequent visualization monitoring, thereby ensuring the representativeness and reliability of the transport path characterization results.

[0038] In some embodiments, by employing a single ion beam scan including 6 Li + A vertical cross-section sample along the permeation direction can obtain samples containing... 6 Li + The secondary ion mass spectrum image of the sample in the vertical cross-section along the permeation direction, from the marked surface to the opposite side, not only visually demonstrates... 6 The concentration gradient and spatial distribution of Li isotopes can also enable direct, in-situ visualization of lithium ion transport paths along different phases or interfaces within composite solid electrolytes.

[0039] In some embodiments, a time-of-flight secondary ion mass spectrometer or a nanosecondary ion mass spectrometer is used, combined with O2. + Cs + Alternatively, scanning with a liquid metal ion beam can generate a distribution map of several ions. 6 Li +Distribution map 7 Li + Distribution maps and characteristic element distribution maps provide key analytical technical support for intuitively revealing the real and detailed transport paths of lithium ions in composite solid electrolytes. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the process for visually detecting the lithium-ion transport path in a composite solid electrolyte according to the present invention.

[0041] Figure 2 As described in Embodiment 1 of this invention 7 Li + A schematic diagram of the SIMS distribution map;

[0042] Figure 3 As described in Embodiment 1 of this invention 6 Li + A schematic diagram of the SIMS distribution map;

[0043] Figure 4 As described in Embodiment 1 of this invention 12 C + A schematic diagram of the SIMS distribution map;

[0044] Figure 5 This is a schematic diagram of the lithium-ion transport path (SIMS) in the composite solid electrolyte in Example 1 of this specification.

[0045] Figure 6 As described in Embodiment 2 of this invention 6 Li + A schematic diagram of the SIMS distribution map;

[0046] Figure 7 As described in Embodiment 2 of this invention 90 Zr 4+ A schematic diagram of the SIMS distribution map;

[0047] Figure 8 As described in Embodiment 2 of this invention 7 Li + A schematic diagram of the SIMS distribution map;

[0048] Figure 9 As described in Embodiment 2 of this invention 12 C + A schematic diagram of the SIMS distribution map;

[0049] Figure 10 As described in Embodiment 3 of this invention 7 Li + A schematic diagram of the SIMS distribution map;

[0050] Figure 11 As described in Embodiment 3 of this invention 6 Li + A schematic diagram of the SIMS distribution map;

[0051] Figure 12 As described in Embodiment 3 of this invention 90 Zr 4+ A schematic diagram of the SIMS distribution map;

[0052] Figure 13 As described in Embodiment 3 of this invention 12 C + A schematic diagram of the SIMS distribution map;

[0053] Figure 14 As described in Embodiment 4 of this invention 6 Li + A schematic diagram of the SIMS distribution map;

[0054] Figure 15 As described in Embodiment 4 of this invention 7 Li + A schematic diagram of the SIMS distribution map;

[0055] Figure 16 As described in Embodiment 4 of this invention 90 Zr 4+ A schematic diagram of the SIMS distribution map;

[0056] Figure 17 As described in Embodiment 4 of this invention 12 C + A schematic diagram of the SIMS distribution map;

[0057] Figure 18 As described in Embodiment 5 of this invention specification 7 Li + A schematic diagram of the SIMS distribution map;

[0058] Figure 19 As described in Embodiment 5 of this invention specification 6 Li + A schematic diagram of the SIMS distribution map;

[0059] Figure 20 As described in Embodiment 5 of this invention specification 12 C + A schematic diagram of the SIMS distribution map;

[0060] Figure 21 The TiO in Example 5 of this invention specification 2+ A schematic diagram of the SIMS distribution map. Detailed Implementation

[0061] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0062] 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0064] The purpose of this invention is to provide a visualization detection method for lithium-ion transport paths in composite solid electrolytes, so as to overcome the problems existing in the prior art. This method can realize the direct visualization of lithium-ion transport paths in composite solid electrolytes, and transform the abstract transport mechanism into an intuitive transport path image.

[0065] Example 1:

[0066] This embodiment provides a method for visually detecting lithium-ion transport paths in composite solid electrolytes. (See [link to relevant documentation]). Figure 1 This includes the following steps:

[0067] Step 1, perform the composite solid electrolyte treatment. 6 Li isotope selective labeling, wherein the composite solid electrolyte is a PEO-LiTFSI / LLZO (polyethylene oxide-lithium bis(trifluoromethanesulfonyl)imide / garnet-type lithium lanthanum zirconium oxide) composite solid electrolyte membrane.

[0068] Specifically, the preparation method of the PEO-LiTFSI / LLZO composite solid electrolyte membrane includes: dissolving 0.4349 g of LiTFSI (Lithium bis trifluoromethanesulfonyl imide) and 1 g of PEO (Polyethylene Oxide) in 25 mL of anhydrous acetonitrile and stirring for 12 h to obtain a stirred solution, wherein the molar ratio of Li ions to EO (ethylene oxide unit) is 1:15; and adding 3.3481 g (particle size approximately 10 μm) of tantalum-doped LLZO (Li7La3Zr2O) 12 Tantalum-doped LLZO solid electrolyte micron particles were added to the stirred solution to obtain a mixed solution. The mixed solution was then cast onto PTFE (Polytetrafluoroethylene Membrane), dried at 25°C, and then vacuum dried at 60°C for 12 h to obtain a PEO-LiTFSI / LLZO composite solid electrolyte membrane. The tantalum-doped LLZO solid electrolyte micron particles accounted for 70% of the total mass of the PEO-LiTFSI / LLZO composite solid electrolyte membrane.

[0069] Specifically, PEO is a polymer matrix, comprising a PEO phase; LLZO is an inorganic lithium-ion conductor material, comprising an LLZO phase; and LiTFSI is a material containing... 7 Li + Lithium salts.

[0070] Specifically, the process of processing the composite solid electrolyte... 6 Li isotope selective labeling, specifically including:

[0071] use 6 Li metal foil is used as the anode (negative electrode). 7 Li metal foil was used as the cathode (positive electrode) and assembled with a PEO-LiTFSI / LLZO composite solid electrolyte membrane to form a coin cell. The surface of the PEO-LiTFSI / LLZO composite solid electrolyte membrane opposite to the anode was used as the marking surface. The symmetrical cell was subjected to a 0.5 mA cm⁻¹ pressure at 60 °C. -2 Constant current polarization for 20 minutes, complete. 6 Li isotope selective labeling.

[0072] Step 2, for 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing... 6 Li + Vertical cross-sectional samples along the permeation direction, specifically including:

[0073] In an argon-protected glove box, the symmetric cell was disassembled, and the PEO-LiTFSI / LLZO composite solid electrolyte membrane was removed. After being quenched in liquid nitrogen, the PEO-LiTFSI / LLZO composite solid electrolyte membrane was then subjected to focused ion beam cutting via vacuum transfer to obtain a product containing… 6 Li + A sample with a vertical cross-section along the permeation direction.

[0074] Step 3, for those containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map 7 Li + Distribution maps and feature element distribution maps, specifically including:

[0075] Will include 6 Li + A vertical cross-section sample along the permeation direction was fed into a time-of-flight secondary ion mass spectrometer, using Cs... + One ion beam scan includes 6 Li + Vertical cross-sectional samples along the permeation direction were collected simultaneously. 12 C + (PEO phase), 90 Zr 4+ (LLZO phase) 6 Li + as well as 7 Li + The signal generates 6 Li + Distribution map (tracer lithium transport path) 7 Li + Distribution map 12 C + Distribution map and 90 Zr 4+ Distribution map; see Figure 2 It represents 7 Li + Distribution status; see Figure 3 It represents 6 Li + Distribution status; see Figure 4 It represents 12 C + The distribution state.

[0076] Specifically, the feature element distribution map includes a feature element distribution map for spatial positioning (also known as identification) of the polymer matrix and a feature element distribution map for spatial positioning of the inorganic lithium-ion conductor material. The feature element for spatial positioning of the polymer matrix is ​​carbon, which in this embodiment is... 12 C + The characteristic elements of inorganic lithium-ion conductor materials used for spatial positioning are metallic elements or ion groups in the inorganic lithium-ion conductor materials, which in this embodiment are... 90 Zr 4+ .

[0077] Step 4, for 6 Li + Distribution map 7 Li + The distribution maps and characteristic element distribution maps were used to detect the transport paths of lithium ions in the composite solid electrolyte, specifically including:

[0078] Will 6 Li + Distribution map and 7 Li + The distribution maps are overlaid to... 6 Li + Distribution map and 12 C + Distribution map 90 Zr 4+ Spatial overlay and correlation analysis were performed on the distribution map.

[0079] See Figure 5 The results showed 6 Li + Concentrated within the LLZO phase, 6 Li + It is extremely rare in the PEO phase. 7 Li + The relatively uniform distribution in PEO and LLZO indicates that... 6 Li + The preferential transport along the LLZO phase indicates that in this embodiment, the transport path of lithium ions is dominated by the bulk transport mechanism.

[0080] Example 2:

[0081] This embodiment provides a method for visually detecting lithium-ion transport paths in composite solid electrolytes. (See [link to relevant documentation]). Figure 1 This includes the following steps:

[0082] Step 1, perform the composite solid electrolyte treatment. 6 Li isotope selective labeling, wherein the composite solid electrolyte is a PEO-LiTFSI / LLZO composite solid electrolyte membrane.

[0083] Specifically, the preparation method of the PEO-LiTFSI / LLZO composite solid electrolyte membrane includes: dissolving 0.4349 g of LiTFSI and 1 g of PEO in 8.5 mL of anhydrous acetonitrile and stirring for 12 h to obtain a stirred solution, wherein the molar ratio of Li ions to EO (ethylene oxide unit) is 1:15; adding 0.1594 g (approximately 10 μm in diameter) of tantalum-doped LLZO solid electrolyte micron particles to the stirred solution to obtain a mixed solution; casting the mixed solution onto PTFE; drying at 25°C; and then vacuum drying at 60°C for 12 h to obtain the PEO-LiTFSI / LLZO composite solid electrolyte membrane, wherein the tantalum-doped LLZO solid electrolyte micron particles account for 10% of the total mass of the PEO-LiTFSI / LLZO composite solid electrolyte membrane.

[0084] Specifically, PEO is a polymer matrix, comprising a PEO phase; LLZO is an inorganic lithium-ion conductor material, comprising an LLZO phase; and LiTFSI is a material containing... 7 Li + Lithium salts.

[0085] Specifically, the process of processing the composite solid electrolyte... 6 Selective labeling of Li isotopes, specifically including:

[0086] use 6 Li metal foil is used as the anode (negative electrode). 7 Li metal foil was used as the cathode (positive electrode) and assembled with a PEO-LiTFSI / LLZO composite solid electrolyte membrane to form a coin cell. The surface of the PEO-LiTFSI / LLZO composite solid electrolyte membrane opposite to the anode was used as the marking surface. The symmetrical cell was subjected to a 0.1 mA cm⁻¹ pressure at 60 °C. -2 Constant current polarization for 40 minutes, completed. 6 Li isotope selective labeling.

[0087] Step 2, for 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing... 6 Li + Vertical cross-sectional samples along the permeation direction, specifically including:

[0088] In an argon-protected glove box, the symmetric cell was disassembled, and the PEO-LiTFSI / LLZO composite solid electrolyte membrane was removed. After being quenched in liquid nitrogen, the PEO-LiTFSI / LLZO composite solid electrolyte membrane was then subjected to focused ion beam cutting via vacuum transfer to obtain a product containing… 6Li + A sample with a vertical cross-section along the permeation direction.

[0089] Step 3, for those containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map (tracer lithium transport path) 7 Li + Distribution maps and feature element distribution maps, specifically including:

[0090] Will contain 6 Li + A vertical cross-section sample along the permeation direction was fed into a time-of-flight secondary ion mass spectrometer, using Ga... + (Liquid metal ion beam) A single ion beam scan includes 6 Li + Vertical cross-sectional samples along the permeation direction were collected simultaneously. 12 C + (PEO phase), 90 Zr 4+ (LLZO phase) 6 Li + as well as 7 Li + The signal generates 6 Li + Distribution map 7 Li + Distribution map 12 C + Distribution map and 90 Zr 4 + Distribution map; see Figure 6 It represents 6 Li + Distribution status; see Figure 7 It represents 90 Zr 4+ Distribution status; see Figure 8 It represents 7 Li + Distribution status; see Figure 9 It represents 12 C + The distribution state.

[0091] Specifically, the characteristic element distribution map includes a characteristic element distribution map for spatially positioning the polymer matrix and a characteristic element distribution map for spatially positioning the inorganic lithium-ion conductor material. The characteristic element for spatially positioning the polymer matrix is ​​carbon, which in this embodiment is... 12 C +The characteristic elements of inorganic lithium-ion conductor materials used for spatial positioning are metallic elements or ion groups in the inorganic lithium-ion conductor materials, which in this embodiment are... 90 Zr 4+ .

[0092] Step 4, for 6 Li + Distribution map 7 Li + The distribution maps and characteristic element distribution maps were used to detect the transport paths of lithium ions in the composite solid electrolyte, specifically including:

[0093] Will 6 Li + Distribution map and 7 Li + The distribution maps are overlaid to... 6 Li + Distribution map and 12 C + Distribution map 90 Zr 4+ Spatial overlay and correlation analysis of the distribution map showed that... 6 Li + Concentrated within the PEO phase, 7 Li + The relatively uniform distribution of lithium ions in the LLZO phase indicates that, in this embodiment, the transport path of lithium ions is dominated by the PEO phase transport mechanism.

[0094] Example 3:

[0095] This embodiment provides a method for visually detecting lithium-ion transport paths in composite solid electrolytes. (See [link to relevant documentation]). Figure 1 This includes the following steps:

[0096] Step 1, perform the composite solid electrolyte treatment. 6 Li isotope selective labeling, wherein the composite solid electrolyte is a PEO-LiTFSI / LLZO composite solid electrolyte membrane.

[0097] Specifically, the preparation method of the PEO-LiTFSI / LLZO composite solid electrolyte membrane includes: dissolving 0.4349 g of LiTFSI and 1 g of PEO in 11 mL of anhydrous acetonitrile and stirring for 12 h to obtain a stirred solution, wherein the molar ratio of Li ions to EO (ethylene oxide unit) is 1:15; adding 0.6149 g (approximately 10 μm in diameter) of tantalum-doped LLZO solid electrolyte micron particles to the stirred solution to obtain a mixed solution; casting the mixed solution onto PTFE; drying at 25°C; and vacuum drying at 60°C for 12 h to obtain the PEO-LiTFSI / LLZO composite solid electrolyte membrane, wherein the tantalum-doped LLZO solid electrolyte micron particles account for 30% of the total mass of the PEO-LiTFSI / LLZO composite solid electrolyte membrane.

[0098] Specifically, PEO is a polymer matrix, comprising a PEO phase; LLZO is an inorganic lithium-ion conductor material, comprising an LLZO phase; and LiTFSI is a material containing... 7 Li + Lithium salts.

[0099] Specifically, the process of processing the composite solid electrolyte... 6 Li isotope selective labeling, specifically including:

[0100] use 6 Li metal foil is used as the anode (negative electrode). 7 Li metal foil was used as the cathode (positive electrode) and assembled with a PEO-LiTFSI / LLZO composite solid electrolyte membrane to form a coin cell. The surface of the PEO-LiTFSI / LLZO composite solid electrolyte membrane opposite to the anode was used as the marking surface. The symmetrical cell was subjected to a 0.1 mA cm⁻¹ pressure at 60 °C. -2 Constant current polarization for 30 minutes, complete. 6 Li isotope selective labeling.

[0101] Step 2, for 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing... 6 Li + The sample is a cross-sectional section perpendicular to the direction of permeation, specifically including:

[0102] In an argon-protected glove box, the symmetric cell was disassembled, and the PEO-LiTFSI / LLZO composite solid electrolyte membrane was removed. After being quenched in liquid nitrogen, the PEO-LiTFSI / LLZO composite solid electrolyte membrane was then subjected to focused ion beam cutting via vacuum transfer to obtain a product containing… 6 Li +A sample with a vertical cross-section along the permeation direction.

[0103] Step 3, for those containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map (tracer lithium transport path) 7 Li + Distribution maps and feature element distribution maps, specifically including:

[0104] Will contain 6 Li + The vertical cross-section sample along the permeation direction was sent into a time-of-flight secondary ion mass spectrometer, using O2. + One ion beam scan includes 6 Li + Vertical cross-sectional samples along the permeation direction were collected simultaneously. 12 C + (PEO phase), 90 Zr 4+ (LLZO phase) 6 Li + as well as 7 Li + The signal generates 6 Li + Distribution map 7 Li + Distribution map 12 C + Distribution map and 90 Zr 4+ Distribution map; see Figure 10 It represents 7 Li + Distribution status; see Figure 11 It represents 6 Li + Distribution status; see Figure 12 It represents 90 Zr 4+ Distribution status; see Figure 13 It represents 12 C + The distribution state.

[0105] Specifically, the characteristic element distribution map includes a characteristic element distribution map for spatially positioning the polymer matrix and a characteristic element distribution map for spatially positioning the inorganic lithium-ion conductor material. The characteristic element for spatially positioning the polymer matrix is ​​carbon, which in this embodiment is... 12 C +The characteristic elements of inorganic lithium-ion conductor materials used for spatial positioning are metallic elements or ion groups in the inorganic lithium-ion conductor materials, which in this embodiment are... 90 Zr 4+ .

[0106] Step 4, for 6 Li + Distribution map 7 Li + The distribution maps and characteristic element distribution maps were used to detect the transport paths of lithium ions in the composite solid electrolyte, specifically including:

[0107] Will 6 Li + Distribution map and 7 Li + The distribution maps are overlaid to... 6 Li + Distribution map and 12 C + Distribution map 90 Zr 4+ Spatial overlay and correlation analysis of the distribution map showed that... 6 Li + The fact that lithium ions are simultaneously distributed in both the PEO and LLZO phases indicates that in this embodiment, lithium ions are transported in both the PEO and LLZO phases.

[0108] Example 4:

[0109] This embodiment provides a method for visually detecting lithium-ion transport paths in composite solid electrolytes. (See [link to relevant documentation]). Figure 1 This includes the following steps:

[0110] Step 1, perform the composite solid electrolyte treatment. 6 Li isotope selective labeling, wherein the composite solid electrolyte is a PEO-LiTFSI / LLZO composite solid electrolyte membrane.

[0111] Specifically, the preparation method of the PEO-LiTFSI / LLZO composite solid electrolyte membrane includes: dissolving 0.4349 g of LiTFSI and 1 g of PEO in 13.7 mL of anhydrous acetonitrile and stirring for 12 h to obtain a stirred solution, wherein the molar ratio of Li ions to EO (ethylene oxide unit) is 1:15; adding 1.174 g (approximately 10 μm in diameter) of tantalum-doped LLZO solid electrolyte microparticles to the stirred solution to obtain a mixed solution; casting the mixed solution onto PTFE; drying at 25°C; and vacuum drying at 60°C for 12 h to obtain the PEO-LiTFSI / LLZO composite solid electrolyte membrane, wherein the tantalum-doped LLZO solid electrolyte microparticles account for 45% of the total mass of the PEO-LiTFSI / LLZO composite solid electrolyte membrane.

[0112] Specifically, PEO is a polymer matrix, comprising a PEO phase; LLZO is an inorganic lithium-ion conductor material, comprising an LLZO phase; and LiTFSI is a material containing... 7 Li + Lithium salts.

[0113] Specifically, the process of processing the composite solid electrolyte... 6 Li isotope selective labeling, specifically including:

[0114] use 6 Li metal foil is used as the anode (negative electrode). 7 Li metal foil was used as the cathode (positive electrode) and assembled with a PEO-LiTFSI / LLZO composite solid electrolyte membrane to form a coin cell. The surface of the PEO-LiTFSI / LLZO composite solid electrolyte membrane opposite to the anode was used as the marking surface. The symmetrical cell was subjected to a 0.1 mA cm⁻¹ pressure at 60 °C. -2 Constant current polarization for 30 minutes, complete. 6 Li isotope selective labeling.

[0115] Step 2, for 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing... 6 Li + Vertical cross-sectional samples along the permeation direction, specifically including:

[0116] In an argon-protected glove box, the symmetric cell was disassembled, and the PEO-LiTFSI / LLZO composite solid electrolyte membrane was removed. After being quenched in liquid nitrogen, the PEO-LiTFSI / LLZO composite solid electrolyte membrane was then subjected to focused ion beam cutting via vacuum transfer to obtain a product containing… 6 Li +A sample with a vertical cross-section along the permeation direction.

[0117] Step 3, for those containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map (tracer lithium transport path) 7 Li + Distribution maps and feature element distribution maps, specifically including:

[0118] Will include 6 Li + A vertical cross-section sample along the permeation direction was fed into a time-of-flight secondary ion mass spectrometer, using Cs... + One ion beam scan includes 6 Li + Vertical cross-sectional samples along the permeation direction were collected simultaneously. 12 C + (PEO phase), 90 Zr 4+ (LLZO phase) 6 Li + as well as 7 Li + The signal generates 6 Li + Distribution map 7 Li + Distribution map 12 C + Distribution map and 90 Zr 4+ Distribution map; see Figure 14 It represents 6 Li + Distribution status; see Figure 15 It represents 7 Li + Distribution status; see Figure 16 It represents 90 Zr 4+ Distribution status; see Figure 17 It represents 12 C + The distribution state.

[0119] Specifically, the characteristic element distribution map includes a characteristic element distribution map for spatially positioning the polymer matrix and a characteristic element distribution map for spatially positioning the inorganic lithium-ion conductor material. The characteristic element for spatially positioning the polymer matrix is ​​carbon, which in this embodiment is... 12 C +The characteristic elements of inorganic lithium-ion conductor materials used for spatial positioning are metallic elements or ion groups in the inorganic lithium-ion conductor materials, which in this embodiment are... 90 Zr 4+ .

[0120] Step 4, for 6 Li + Distribution map 7 Li + The distribution maps and characteristic element distribution maps were used to detect the transport paths of lithium ions in the composite solid electrolyte, specifically including:

[0121] Will 6 Li + Distribution map and 7 Li + The distribution maps are overlaid to... 6 Li + Distribution map and 12 C + Distribution map 90 Zr 4+ Spatial overlay and correlation analysis of the distribution map showed that... 6 Li + It is distributed simultaneously in both the PEO and LLZO phases, and 7 Li + The overall structure is relatively uniform, mainly concentrated in PEO, indicating that in this embodiment, both the PEO phase and the LLZO phase can transport lithium ions, and the lithium ion transport path is gradually transitioning to the LLZO phase as the main component.

[0122] Example 5:

[0123] This embodiment provides a method for visually detecting lithium-ion transport paths in composite solid electrolytes. (See [link to relevant documentation]). Figure 1 This includes the following steps:

[0124] Step 1, perform the composite solid electrolyte treatment. 6 Li isotope selective labeling, wherein the composite solid electrolyte is a PEO-LiTFSI / LLTO composite solid electrolyte membrane.

[0125] Specifically, the preparation method of the PEO-LiTFSI / LLTO composite solid electrolyte membrane includes: dissolving 0.4349 g of LiTFSI and 1 g of PEO in 8.5 mL of anhydrous acetonitrile and stirring for 12 h to obtain a stirred solution, wherein the molar ratio of Li ions to EO (ethylene oxide unit) is 1:15; adding 0.1594 g (approximately 10 μm in diameter) of tantalum-doped LLTO (Lithium Lanthanum Titanium Oxide) solid electrolyte micron particles to the stirred solution to obtain a mixed solution; casting the mixed solution onto PTFE; drying at 25°C; and then vacuum drying at 60°C for 12 h to obtain the PEO-LiTFSI / LLTO composite solid electrolyte membrane, wherein the tantalum-doped LLTO solid electrolyte micron particles account for 10% of the total mass of the PEO-LiTFSI / LLTO composite solid electrolyte membrane.

[0126] Specifically, PEO is a polymer matrix, comprising a PEO phase; LLTO is an inorganic lithium-ion conductor material, comprising an LLTO phase; and LiTFSI is a material containing... 7 Li + Lithium salts.

[0127] Specifically, the process of processing the composite solid electrolyte... 6 Li isotope selective labeling, specifically including:

[0128] use 6 Li metal foil is used as the anode (negative electrode). 7 Li metal foil was used as the cathode (positive electrode) and assembled with a PEO-LiTFSI / LLTO composite solid electrolyte membrane to form a coin cell. The surface of the PEO-LiTFSI / LLTO composite solid electrolyte membrane opposite to the anode was used as the marking surface. The symmetrical cell was subjected to a 0.1 mA cm⁻¹ pressure at 60 °C. -2 Constant current polarization for 30 minutes, complete. 6 Li isotope selective labeling.

[0129] Step 2, for 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing... 6 Li + Vertical cross-sectional samples along the permeation direction, specifically including:

[0130] In an argon-protected glove box, the symmetric cell was disassembled, and the PEO-LiTFSI / LLTO composite solid electrolyte membrane was removed. After liquid nitrogen quenching, the PEO-LiTFSI / LLTO composite solid electrolyte membrane was subjected to focused ion beam cutting via vacuum transfer to obtain a product containing…6 Li + A sample with a vertical cross-section along the permeation direction.

[0131] Step 3, for those containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map 7 Li + Distribution maps and feature element distribution maps, specifically including:

[0132] Will include 6 Li + A vertical cross-section sample along the permeation direction was fed into a time-of-flight secondary ion mass spectrometer, using Cs... + One ion beam scan includes 6 Li + Vertical cross-sectional samples along the permeation direction were collected simultaneously. 12 C + (PEO phase), TiO 2+ (LLTO phase) 6 Li + as well as 7 Li + The signal generates 6 Li + Distribution map 7 Li + Distribution map 12 C + Distribution diagram and TiO 2+ Distribution map; see Figure 18 It represents 7 Li + Distribution status; see Figure 19 It represents 6 Li + Distribution status; see Figure 20 It represents 12 C + Distribution status; see Figure 21 Characterized TiO 2+ The distribution state.

[0133] Specifically, the characteristic element distribution map includes a characteristic element distribution map for spatially positioning the polymer matrix and a characteristic element distribution map for spatially positioning the inorganic lithium-ion conductor material. The characteristic element for spatially positioning the polymer matrix is ​​carbon, which in this embodiment is... 12 C + The characteristic elements of the inorganic lithium-ion conductor material used for spatial positioning are metallic elements or ion groups in the inorganic lithium-ion conductor material, which in this embodiment is TiO2.2+ .

[0134] Step 4, for 6 Li + Distribution map 7 Li + The distribution maps and characteristic element distribution maps were used to detect the transport paths of lithium ions in the composite solid electrolyte, specifically including:

[0135] Will 6 Li + Distribution map and 7 Li + The distribution maps are overlaid to... 6 Li + Distribution map and 12 C + Distribution diagram, TiO 2+ Spatial overlay and correlation analysis of the distribution map showed that... 6 Li + It is concentrated at the interface between the PEO phase and the LLTO phase, and extends along the interface. 6 Li + It exhibits a continuous distribution at the interface between the PEO phase and the LLTO phase. 7 Li + The relatively uniform distribution of lithium ions in the LLTO phase confirms that, in this embodiment, the transport path of lithium ions is dominated by the interfacial transport mechanism.

[0136] The core of step 1 in this embodiment 1-5 is to create a localized area rich in the stable isotope lithium-6 on one side of the composite solid electrolyte. 6 The "tracer source" of Li; obtained in step 3 of this embodiment 1-5 6 Li + The distribution map represents the distribution of tracer lithium injected or exchanged "dynamically". 7 Li + The distribution map represents the "static" background lithium distribution of the material. 12 C + The distribution diagram represents the polymer matrix phase. 90 Zr 4+ The distribution diagram represents the phase of inorganic lithium-ion conductor materials. 12 C + Distribution map and characteristic ion distribution map of inorganic phase ( 90 Zr 4+ Distribution map or TiO 2+ Distribution diagrams are used to characterize the microstructure of composite solid electrolytes.

[0137] In this embodiment 1-5, by setting... 6Li isotope selective labeling strategy, combined with secondary ion mass spectrometry analysis, can clearly distinguish submicron-scale phases and interfaces, directly obtaining... 6 Li + The distribution diagram of each phase structure in the composite solid electrolyte allows for precise judgment. 6 Li + Whether the lithium-ion transport occurs in the bulk phase or at the interface, this distinguishes different lithium-ion transport mechanisms and provides a direct basis for optimizing material formulations. 6 Li / 7 The Li isotope differentiation effectively separated dynamically transported lithium from static background lithium, with a high signal-to-noise ratio and clear conclusions.

[0138] Therefore, Examples 1-5 allow for direct observation and analysis of the lithium-ion transport pathways, interfacial behavior, and dominant transport mechanisms within the composite solid-state electrolyte, enabling visualization of lithium-ion transport pathways in the composite solid-state electrolyte and transforming abstract mechanisms into intuitive visual evidence. This method is applicable to several types of composite solid-state electrolyte systems and has broad application prospects.

[0139] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects.

[0140] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention fall within the scope of protection of this invention.

Claims

1. A method for visually detecting lithium-ion transport paths in composite solid electrolytes, characterized in that, Includes the following steps: To conduct composite solid electrolyte 6 Li isotope selective labeling; the composite solid electrolyte comprises a polymer matrix, an inorganic lithium-ion conductor material distributed within the polymer matrix, and a lithium-ion electrolyte containing... 7 Li + The lithium salt; wherein the polymer matrix includes a polymer matrix phase, and the inorganic lithium-ion conductor material includes an inorganic lithium-ion conductor material phase; right 6 Li isotope-selectively labeled composite solid electrolytes were prepared sequentially using rapid physical methods and in-situ cross-sectional methods, containing... 6 Li + A sample with a vertical cross-section along the permeation direction; For containing 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, and ions were generated simultaneously. 6 Li + Distribution map 7 Li + Distribution map and characteristic element distribution map; the characteristic element distribution map includes a characteristic element distribution map for spatial positioning of the polymer matrix and a characteristic element distribution map for spatial positioning of the inorganic lithium-ion conductor material; wherein, the characteristic element for spatial positioning of the polymer matrix is ​​carbon, and the characteristic element for spatial positioning of the inorganic lithium-ion conductor material is a metal element or ion group in the inorganic lithium-ion conductor material. right 6 Li + Distribution map 7 Li + The distribution maps and characteristic element distribution maps were used to detect the transport paths of lithium ions in the composite solid electrolyte, specifically including: Will 6 Li + Distribution map and 7 Li + The distribution maps are overlaid to... 6 Li + Spatial overlay and correlation analysis were performed between the distribution map and the feature element distribution map; like 6 Li + If the lithium ions are concentrated within the inorganic lithium-ion conductor material phase, then the transport path of lithium ions is a bulk transport mechanism. like 6 Li + If the lithium ions are concentrated at the interface between the inorganic lithium-ion conductor material phase and the polymer matrix phase and extend along the interface, then the lithium-ion transport path is the interfacial transport mechanism.

2. The method for visually detecting lithium-ion transport paths in a composite solid electrolyte according to claim 1, characterized in that, The composite solid electrolyte is a PEO-LiTFSI / LLZO composite solid electrolyte membrane or a PEO-LiTFSI / LLTO composite solid electrolyte membrane.

3. The method for visually detecting lithium-ion transport paths in a composite solid electrolyte according to claim 1, characterized in that, The process of composite solid electrolyte 6 Li isotope selective labeling, specifically including: use 6 Li metal is used as the anode, and a symmetrical cell is assembled with a composite solid electrolyte. The surface of the composite solid electrolyte opposite to the anode is used as a marking surface. A constant current is applied to the symmetrical cell for polarization, thus completing the process. 6 Li isotope selective labeling.

4. The method for visually detecting lithium-ion transport paths in a composite solid electrolyte according to claim 3, characterized in that, The current density of the constant current is 0.1–0.5 mA / cm². 2 The polarization time is 20–40 min.

5. The method for visually detecting lithium-ion transport paths in a composite solid electrolyte according to claim 1, characterized in that, The rapid physical method includes liquid nitrogen quenching; the in-situ section method includes focused ion beam cutting.

6. The method for visually detecting lithium-ion transport paths in a composite solid electrolyte according to claim 1, characterized in that, The pair includes 6 Li + Secondary ion mass spectrometry analysis was performed on the vertical cross-section sample along the permeation direction, specifically including: Using a single ion beam scan includes 6 Li + A sample with a vertical cross-section along the permeation direction.

7. The method for visually detecting lithium-ion transport paths in a composite solid electrolyte according to claim 6, characterized in that, The secondary ion mass spectrometry analysis was performed using a time-of-flight secondary ion mass spectrometer or a nano-secondary ion mass spectrometer. The primary ion beam includes O2 + Cs + Or liquid metal ion beam.

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