An ultrahigh electronic conductivity organic cathode material, a preparation method thereof and a battery

Abstract

The application discloses an organic cathode material with super-high electron conductivity, which is Li4C8H2O6-TCNQ, and the Li4C8H2O6-TCNQ is a charge transfer complex formed by raw material Li4C8H2O6 and TCNQ. The organic cathode material has super-high electron conductivity, and when the organic cathode material is used in a full solid-state battery, the full solid-state battery has better electrical performance.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to an organic cathode material with ultra-high electronic conductivity, its preparation method, and a battery thereof. Background Technology

[0002] Compared to inorganic materials, organic electrode materials possess advantages such as abundant resources, high theoretical specific capacity, mild synthesis conditions, and designable molecular structures, thus attracting widespread research attention worldwide. However, organic electrode materials typically suffer from low density, low electronic conductivity, and high solubility in liquid electrolytes. This severely limits their electrochemical performance in traditional lithium-ion batteries (LIBs). The application of organic electrode materials in all-solid-state batteries (ASSBs) can fundamentally suppress their solubility and improve their electrochemical performance. Furthermore, solid-state electrolytes have now achieved ionic conductivity comparable to or even higher than that of lithium-ion batteries (LIBs).

[0003] In recent years, several organic cathodes for sulfide-based ASSBs have been developed and researched. However, due to the extremely low electronic conductivity of organic cathode materials, their application in solid-state batteries, especially at high rates, still faces many challenges. Of particular concern is the significant decrease in the utilization rate of organic cathode materials at high rates. Researchers are working to improve the electronic conductivity of organic materials to enhance their utilization in solid-state batteries. Some researchers have synthesized composite materials or mixtures of organic electrode materials using conductive frameworks based on carbonaceous materials. These conductive frameworks enhance the electrode's conductivity and provide anchoring points for redox organic compounds, thereby improving power and capacity retention. However, the large amount of additional matrix or support significantly increases the electrode's weight, thus reducing the discharge specific capacity.

[0004] Developing an organic cathode material with higher electronic conductivity can promote the integration of solid electrolytes and organic electrodes, thus potentially leading to all-solid-state batteries with high discharge specific capacity and good cycle stability. Summary of the Invention

[0005] This invention addresses the problems in the prior art by disclosing an organic cathode material with ultra-high electronic conductivity. The organic cathode material of this invention has ultra-high electronic conductivity, and when used in all-solid-state batteries, the all-solid-state batteries exhibit better electrical performance.

[0006] This invention is achieved through the following technical solution:

[0007] The present invention provides an organic cathode material with ultra-high electronic conductivity, wherein the organic cathode material is Li4C8H2O6-TCNQ, and Li4C8H2O6-TCNQ is a charge-transfer complex formed by Li4C8H2O6 and TCNQ (7,7,8,8-tetracyano-p-benzodiquinone dimethane).

[0008] The above design of the present invention: Li4C8H2O6 material is a good electron donor, while TCNQ, as an acceptor molecule, has good electron-deficient properties. Li4C8H2O6 and TCNQ form a charge-transfer complex. The complex contains a dense electron cloud, which flows between the two molecules, which is conducive to the free movement of electrons, thereby improving the electronic conductivity of the organic cathode material.

[0009] As a further embodiment, the molar ratio of Li4C8H2O6 to TCNQ in the organic cathode material is (1-2):(1-2).

[0010] As a further embodiment, the molar ratio of Li4C8H2O6 to TCNQ in the organic cathode material is 1:2.

[0011] As a further embodiment, the organic cathode material has characteristic peaks at 10.5°, 15.1°, 16.7°, 21.3°, 26.6°, 27.8°, 30.2°, 32.2°, and 38.3° in its X-ray powder diffraction pattern expressed at a diffraction angle of 2θ.

[0012] The present invention also provides a method for preparing the organic cathode material, the method comprising weighing Li4C8H2O6 and TCNQ according to the molar ratio of Li4C8H2O6 and TCNQ respectively, then adding them to a solvent, stirring, and drying to obtain the organic cathode material of the present invention.

[0013] As a further embodiment, the solvent comprises 1,3-dioxolane; the molar ratio of Li4C8H2O6 to TCNQ is (1-2):(1-2). Choosing a suitable solvent and the molar ratio of Li4C8H2O6 to TCNQ is beneficial for obtaining organic cathode materials with better electronic conductivity. Furthermore, organic cathode materials used in solid-state batteries can maintain relatively stable capacity at high rates.

[0014] As a further option, the stirring time is 40h-55h.

[0015] As a further embodiment, the drying temperature is 70℃-90℃, and the drying time is 10h-14h.

[0016] The present invention also provides a cathode having the aforementioned organic cathode material. In the art, during battery discharge, the cathode represents the positive electrode of the battery, and the anode represents the negative electrode of the battery.

[0017] As a further embodiment, the cathode also includes a conductive agent and a sulfide solid electrolyte.

[0018] As a further option, the organic cathode material accounts for 15%-25% of the cathode by mass.

[0019] As a further embodiment, the conductive agent includes one or more of graphene, conductive carbon black, conductive graphite, carbon fiber, carbon nanotubes, multi-arm carbon nanotubes, Ketjen black, porous carbon, carbon cloth, graphite, hard carbon, coke, soft carbon, acetylene black, carbon whiskers, and needle coke.

[0020] As a further embodiment, the sulfide solid electrolyte includes one or more of crystalline sulfide solid electrolytes and microcrystalline glassy sulfide solid electrolytes.

[0021] As a further embodiment, the crystalline sulfide solid electrolyte includes one or more of sulfides with a silver-germanium sulfide structure and sulfides with a Thio-LiSICON structure.

[0022] As a further embodiment, the sulfides of the soursilgermanium ore structure include Li6PS5Cl (lithium-sulfur-phosphorus-chlorine electrolyte).

[0023] As a further embodiment, the sulfide with the Thio-LiSICON structure includes Li 10 GeP2S 12 Based on Li 10 GeP2S 12 The sulfide solid electrolyte obtained after element doping.

[0024] As a further embodiment, the doped element includes one or more of Al, Si, Ga, Sn, N, O, Cl, Br, and I.

[0025] More preferably, the microcrystalline glassy sulfide solid electrolyte includes one or more of the following: sulfides based on the Li2S-P2S5 system and multi-component sulfides obtained by elemental doping of sulfides based on the Li2S-P2S5 system.

[0026] The present invention also provides an all-solid-state battery or electrochemical device having the cathode.

[0027] As a further option, the all-solid-state battery includes a sulfide solid-state battery or a halide solid-state battery.

[0028] As a further option, the all-solid-state battery can be applied to 3C products, including but not limited to computers, tablets, mice, mobile phones, digital cameras, Walkmans, electronic dictionaries, digital audio players, smartwatches, MP3 players, MP4 players, radios, and Bluetooth headsets.

[0029] As a further embodiment, the electrochemical device can be used in end-consumer products, including but not limited to mobile phones, laptops, pen input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, and portable printers.

[0030] As a further embodiment, the electrochemical device can be used in electrical equipment, including large and small electrical equipment. Small electrical equipment includes consumer products, wearable electronic devices, or portable electronic devices; large electrical equipment includes transportation equipment. Transportation equipment includes, but is not limited to, vehicles such as automobiles, motorcycles, electric bicycles, buses, subways, high-speed trains, airplanes, and ships. Wearable electronic devices or portable electronic devices include, but are not limited to, headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, drones, motors, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors. The cathode of this invention is applied in an electrochemical device, which can be housed in the form of an electrochemical device within an electrical equipment. Typically, this electrochemical device includes a battery pack or / and multiple battery modules or / and a single battery module or / and a management system for controlling them.

[0031] The features and beneficial effects of this invention are as follows: the organic cathode material of this invention has ultra-high electronic conductivity, and when the organic cathode material of this invention is used in all-solid-state batteries, the all-solid-state batteries have better electrical performance. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a comparison of the selection of different solvents in this invention, wherein, Figure 1 a is the DC polarization diagram of products with different molar ratios in 1,3-dioxolane and acetonitrile. Figure 1b represents the electronic conductivity of products in 1,3-dioxolane and acetonitrile at different molar ratios; Figure 1 c. Charge-discharge curves of products with different molar ratios in 1,3-dioxolane and acetonitrile; Figure 1 d is a comparison of the cycling performance of DOL (Li4C8H2O6:TCNQ=1:2) and ACN (Li4C8H2O6:TCNQ=1:2).

[0034] Figure 2 The test results for the organic cathode material DOL (Li4C8H2O6:TCNQ = 1:2) of the present invention are shown below. Figure 2 a is a DC polarization diagram of an embodiment and a comparative example of the present invention. Figure 2 b is the electronic conductivity of the embodiments and comparative examples of the present invention. Figure 2 c represents a comparison of the electronic conductivity of organic cathode materials in the embodiments of the present invention with those in other existing literature. Figure 2 d represents the XRD spectra of the embodiments and comparative examples of this invention. Figure 2 e represents the IR spectrum of the materials in the embodiments and comparative examples of this invention.

[0035] Figure 3 The electrical performance test results of the embodiments and comparative examples of the present invention are shown below. Figure 3 a represents the rate performance of the liquid battery in the embodiments and comparative examples of the present invention. Figure 3 b is the charge / discharge curve of the liquid battery in the embodiments and comparative examples of the present invention. Figure 3 c represents the cycle performance of the liquid battery in the embodiments and comparative examples of the present invention. Figure 3 d is the CV curve of the liquid battery in the embodiments and comparative examples of the present invention.

[0036] Figure 4 The electrochemical performance of the embodiments and comparative examples of the present invention in solid-state batteries is shown below. Figure 4 a is the first charge / discharge curve of the embodiments and comparative examples of the present invention in a solid-state battery. Figure 4 b represents the rate performance of the embodiments and comparative examples of the present invention in solid-state batteries. Figure 4 c is the charge / discharge curve of the embodiment of the present invention in a solid-state battery.

[0037] Figure 5 The following are cycle performance and charge / discharge diagrams for embodiments and comparative examples of the present invention, wherein... Figure 5 a represents the cycling performance of the embodiments and comparative examples of the present invention at a rate of 0.5C. Figure 5 b represents the cycling performance of the embodiments and comparative examples of the present invention at a 1C rate. Figure 5 c represents the cycling performance of the embodiments and comparative examples of the present invention at a 2C rate. Figure 5d is a charging / discharging diagram of the embodiments and comparative examples of the present invention at a 2C rate. Detailed Implementation

[0038] To facilitate understanding of the organic cathode material with ultra-high electronic conductivity and its preparation method according to the present invention, a more comprehensive description of the organic cathode material with ultra-high electronic conductivity and its preparation method will be given below, and embodiments of the present invention will be provided, but this does not limit the scope of the present invention.

[0039] The synthesis method of Li4C8H2O6 in this invention includes: the tetralithium salt of 2,5-dihydroxyterephthalic acid (Li4C8H2O6, Li4DHTPA) is prepared by reacting 2,5-dihydroxyterephthalic acid (DHTPA) with lithium methoxide (MeOLi). The raw material DHTPA is commercially available. In a typical synthesis, 2 mL of a MeOLi-based solution (Aldrich, 2.2 M methanol) is added dropwise to 15 mL of a yellow methanol solution containing 198 mg of DHTPA (Aldrich). After reacting for 12 hours, the prepared solid (Li4C8H2O6-CH3OH) is collected by centrifugation, washed repeatedly with absolute methanol by shaking, and then dried overnight under vacuum at 100°C (yield: 98%). The final Li4C8H2O6 is obtained by heating Li4C8H2O6-CH3OH at 220°C. Because Li4DHTPA is sensitive to air and moisture, all operations are performed in an argon-filled glove box, with O2 and H2O concentrations below 1.0 ppm. The raw material Li4C8H2O6 used in this invention is also commercially available.

[0040] Example 1:

[0041] Synthesis of DOL (Li4C8H2O6-TCNQ = 1:2): Li4C8H2O6 and TCNQ were added to 1,3-dioxolane in a molar ratio of 1:2. After stirring for two days, a blue product was generated. The final product was then obtained by drying (drying time was 12 h, drying temperature was 80 °C). TCNQ was purchased from aladdin.

[0042] Example 2:

[0043] Synthesis of DOL (Li4C8H2O6-TCNQ = 1:1): Li4C8H2O6 and TCNQ were added to 1,3-dioxolane in a 1:1 molar ratio. After stirring for two days, a blue product was generated. The final product was then obtained by drying (drying time was 12 h, drying temperature was 80 °C). TCNQ was purchased from aladdin.

[0044] Example 3:

[0045] Synthesis of DOL (Li4C8H2O6-TCNQ = 2:1): Li4C8H2O6 and TCNQ were added to 1,3-dioxolane in a molar ratio of 2:1. After stirring for two days, a blue product was generated. The final product was then obtained by drying (drying time was 12 h, drying temperature was 80 °C). TCNQ was purchased from aladdin.

[0046] Comparative Example 1:

[0047] Synthesis of ACN (Li4C8H2O6-TCNQ = 1:2): Li4C8H2O6 and TCNQ were added to acetonitrile in a molar ratio of 1:2. After stirring for two days, a blue product was generated. The final product was then obtained by drying (drying time was 12 h, drying temperature was 80 °C). TCNQ was purchased from aladdin.

[0048] Comparative Example 2:

[0049] Synthesis of ACN (Li4C8H2O6-TCNQ = 1:1): Li4C8H2O6 and TCNQ were added to acetonitrile in a 1:1 molar ratio. After stirring for two days, a blue product was generated. The final product was then obtained by drying (drying time was 12 h, drying temperature was 80 °C). TCNQ was purchased from aladdin.

[0050] Comparative Example 3:

[0051] Synthesis of ACN (Li4C8H2O6-TCNQ = 2:1): Li4C8H2O6 and TCNQ were added to acetonitrile in a molar ratio of 2:1. After stirring for two days, a blue product was generated. The final product was then obtained by drying (drying time was 12 h, drying temperature was 80 °C). TCNQ was purchased from aladdin.

[0052] Comparative Example 4:

[0053] Material: Li4C8H2O6.

[0054] Comparative Example 5:

[0055] Material TCNQ.

[0056] We also prepared cathodes using different cathode materials. The cathode preparation process included an organic cathode material:Li6PS5Cl:CNTs (carbon nanotubes) ratio of 2:7:1. After weighing each component according to the mass ratio, they were ground in a mortar for 20 minutes to obtain the final composite cathode.

[0057] Synthesis of Li6PS5Cl: 2.14 g Li2S (lithium sulfide), 2.07 g phosphorus pentasulfide (P2S5, 99%, Aladdin), and 0.79 g lithium chloride (LiCl, 99%, Aladdin) were weighed according to the molar ratio and placed into a ball mill jar containing 90 g ZrO2 (zirconia) balls. The ball milling process was carried out at 400 rpm for 24 hours, followed by 48 hours at 600 rpm. The resulting powder was then annealed at 550 °C for 10 hours at a heating rate of 5 °C / min and allowed to cool naturally to room temperature. All the above experiments were conducted under an Ar atmosphere. Li6PS5Cl is also commercially available.

[0058] The composite cathode was assembled into a battery: 80 mg of Li6PS5Cl powder was cold-pressed into a polycarbonate cylinder with an inner wall diameter of 10 mm, and a solid electrolyte particle (SSE particle) was produced at 360 MPa. Next, the composite cathode was uniformly spread on one side of the SSE particle and cold-pressed at 873 MPa for 1 minute. The cathode loading was 1 mg / cm³. 2 Finally, a thin lithium foil is pressed onto the other side of the SSE particles. At 1.8–3.6V with Li... + Between / Li, electrostatic charge / discharge tests were conducted at 55°C using the Land battery testing system at different current densities.

[0059] We also obtained the battery and conducted electrical performance tests.

[0060] Analysis of verification results:

[0061] We have successfully prepared an organic cathode material with ultra-high electronic conductivity using the method of this invention. In this organic cathode, Li4C8H2O6 is an excellent electron donor, while TCNQ, as an acceptor molecule, exhibits good electron-deficient properties. Li4C8H2O6 and TCNQ form a charge-transfer complex with a dense electron cloud that flows between the two molecules, facilitating free electron movement. Using this organic cathode material in solid-state batteries allows for better utilization of the organic cathode material even at high rates, resulting in a better discharge specific capacity.

[0062] In this invention, the molar ratio of Li4C8H2O6 to TCNQ is crucial for the stability of the formed organic cathode material at high rates. A suitable molar ratio leads to higher electronic conductivity. Furthermore, selecting a more suitable solvent is beneficial for the organic cathode material to achieve a higher discharge specific capacity. The solvent needs to dissolve both Li4C8H2O6 and TCNQ and promote the formation of charge-transfer complexes between them. On the other hand, the solvent must not bind to the formed organic cathode material. 1,3-Dioxolane and acetonitrile (ACN) were used as solvents for the formation of charge-transfer complexes between Li4C8H2O6 and TCNQ because they are stable to both materials and have good solubility. Then, charge-transfer complexes were formed in two solvents at three different molar ratios: Li4C8H2O6:TCNQ = 2:1, 1:1, and 1:2, respectively. We named the synthesized charge-transfer complexes according to the type of solvent and the molar ratio of the two materials. For example, the charge-transfer complex formed in 1,3-dioxolane solvent (DOL) with a molar ratio of Li4C8H2O6:TCNQ = 1:2 was named DOL(Li4C8H2O6:TCNQ = 1:2). Therefore, we synthesized a total of six charge-transfer complexes based on two solvents and three molar ratios, such as... Figure 1 As shown in a ( Figure 1 In A2B1, ACN and DOL represent the solvents acetonitrile and 1,3-dioxolane, respectively. In A2B1, A represents Li4C8H2O6, and B represents TCNQ. The numbers in A2B1 represent the molar ratio, which is 2:1 for Li4C8H2O6 and TCNQ, and so on. The electronic conductivity of these six materials was tested using a 15000s DC polarization method to obtain a stable current. The electronic conductivity of these six materials was then calculated. Figure 1 As shown in b. From Figure 1 a and Figure 1 In step b, we found that the charge-transfer complex exhibited the highest conductivity in both solvents at a Li4C8H2O6:TCNQ ratio of 1:2. High electronic conductivity ensures smooth electron transport within the electrode; therefore, compared to composites with other ratios, the Li4C8H2O6:TCNQ = 1:2 composite demonstrates better rate performance and higher capacity. We further tested the charge-discharge specific capacity of these two charge-transfer complexes, and the results are as follows... Figure 1 c- Figure 1As shown in Figure d, it can be seen that the DOL (Li4C8H2O6:TCNQ=1:2) material has a higher discharge specific capacity. The ACN (Li4C8H2O6:TCNQ=1:2) electrode decomposes at 3.28V. We believe this may be because some ACN molecules are bound to ACN (Li4C8H2O6:TCNQ=1:2), and ACN is prone to decomposition under high voltage. We further optimized the molar ratio of Li4C8H2O6:TCNQ to 1:2.

[0063] Building upon the aforementioned work, we further investigated the performance of the organic cathode material of this invention using DOL (Li4C8H2O6:TCNQ = 1:2) as an example. The charge-transfer complex DOL (Li4C8H2O6:TCNQ = 1:2) was successfully synthesized from Li4C8H2O6 and TCNQ in a 1,3-dioxolane solvent, exhibiting an electronic conductivity of 7 × 10⁻⁶. -5 S / cm, hereinafter named Li4C8H2O6-TCNQ. The electronic conductivity (e.g., S / cm) of Li4C8H2O6 and TCNQ was also measured using the DC polarization method. Figure 2 As shown in a), the electronic conductivity of Li4C8H2O6 is 1×10⁻⁶. -7 S / cm, the electronic conductivity of TCNQ is 5 × 10⁻⁶. -8 S / cm (e.g.) Figure 2 (As shown in b). This indicates that the electronic conductivity of the charge-transfer complex Li4C8H2O6-TCNQ is 1000 times higher than that of Li4C8H2O6 and TCNQ alone. From Figure 2 As can be seen, the electronic conductivity of Li4C8H2O6-TCNQ is significantly higher than that of common organic cathode materials in the prior art, indicating that the organic cathode material of this invention possesses ultra-high electronic conductivity. We believe that the enhanced electronic conductivity of the charge-transfer complex of this invention is due to the formation of an enhanced electron cloud between Li4C8H2O6 and TCNQ through π-π interactions, thereby establishing an electron transport channel and improving the conductivity of the material.

[0064] To verify that the Li4C8H2O6-TCNQ material is a charge-transfer complex, rather than a mixture of Li4C8H2O6 and TCNQ, we performed XRD and infrared spectroscopy analyses on these three materials. Figure 2 In the XRD pattern of d, it can be seen that the O peak position of Li4C8H2O6-TCNQ is roughly the same as that of Li4C8H2O6 and TCNQ. However, this peak disappears at around 25° and a new peak appears at around 16°. This proves that Li4C8H2O6-TCNQ maintains the basic structure of Li4C8H2O6 and TCNQ, while generating interactions and producing a new structure. Figure 2e shows the infrared spectra of the three materials. The C≡N absorption peak of Li₄C₈H₂O₆-TCNQ is shown at 2204 cm⁻¹. -1 The C≡N absorption peak of TCNQ (2222 cm⁻¹) is similar to that of TCNQ. -1 Compared to ), the redshift was 18cm. -1 This is due to the donation of O electrons from Li4C8H2O6. In Li4C8H2O6-TCNQ, there is a C≡N related CC absorption peak (1182 cm⁻¹). -1 The corresponding absorption peak in TCNQ (1125 cm⁻¹) -1 Compared to the previous year, the blue color shifted by 57cm. -1 Because the O electron cloud of Li4C8H2O6 flows to TCNQ, it weakens the influence of C≡N on CC, thus strengthening the CC bond energy. Simultaneously, the CO absorption peak of Li4C8H2O6-TCNQ (1325 cm⁻¹) is observed. -1 ) and Li4C8H2O6 (1231cm) -1 Compared to the previous year, the blue color shifted by 94cm. -1 This fully demonstrates that there is an O-electron interaction between the charge-transfer complex Li4C8H2O6-TCNQ and Li4C8H2O6-TCNQ, with the electron cloud flowing between them.

[0065] We also conducted electrical performance tests on the embodiments of the present invention and the comparison, and the results are as follows: Figure 3 As shown. Among them, Figure 3 The rate performance of Li4C8H2O6, TCNQ, and the charge-transfer complex Li4C8H2O6-TCNQ is shown. It can be seen that the rate performance of the Li4C8H2O6-TCNQ electrode is significantly improved. The capacities of the Li4C8H2O6-TCNQ composite material at 0.1C, 0.5C, 2C, and 10C are 166.9 mAh / g, 150.1 mAh / g, 126.7 mAh / g, and 107.9 mAh / g, respectively (e.g., ...). Figure 3 (As shown in a). Li4C8H2O6, TCNQ, and other proportions of the charge-transfer complex Li4C8H2O6-TCNQ exhibit lower capacities due to their lower electronic conductivity. From Figure 3 As can be seen from the charge-discharge curves of b, the Li4C8H2O6-TCNQ, Li4C8H2O6 and TCNQ electrodes all exhibit stable charge-discharge, but the discharge capacity of Li4C8H2O6-TCNQ is higher than all of them, which is due to its improved electronic conductivity. Figure 3 c shows the cycling performance of the three materials, and it can be seen that Li4C8H2O6-TCNQ has a higher initial discharge capacity in the liquid battery. Figure 3Figure d shows the CV curves of the three materials. It can be seen that two of the four peaks of Li4C8H2O6-TCNQ (2.85V, 3.33V) are consistent with the peaks of TCNQ, while the other two peaks (2.5V, 2.7V) originate from Li4C8H2O6. Compared with the two original materials, the oxidation peak of Li4C8H2O6-TCNQ is shifted to a lower voltage, while the reduction peak is shifted to a higher voltage. The decrease in electrode polarization further demonstrates the enhanced electronic conductivity of the charge-transfer complex.

[0066] We then compared the electrochemical performance of the embodiments and comparative examples of the present invention in solid-state batteries. Since increased electronic conductivity may lead to the decomposition of sulfide electrolytes, we compared the charge and discharge capabilities of Li4C8H2O6-TCNQ with Li6PS5Cl and Li3InCl6 as electrolytes, respectively. (The remaining text appears to be incomplete and requires further context.) Figure 4 As shown in Figure a, the battery using Li6PS5Cl as the electrolyte exhibits an initial specific capacity of 192.2 mAh / g, while the battery using Li3InCl6 as the electrolyte exhibits an initial capacity of 206.8 mAh / g, which is higher than that of Li6PS5Cl. Furthermore, the first coulombic efficiency of the electrode using Li3InCl6 is as high as 99.35%, while the first coulombic efficiency of the electrode using Li6PS5Cl is only 87.38%, indicating that Li3InCl6 has better interfacial stability with the organic cathode material of this invention. Therefore, we will use Li3InCl6 as the electrolyte. Figure 4 b shows the rate performance of the three materials, and it can be seen that the rate performance of the Li4C8H2O6-TCNQ composite material is superior to that of the two original materials. The capacities of the Li4C8H2O6-TCNQ composite material at 0.1C, 0.5C, 2C, and 10C are 203.5 mAh / g, 155.8 mAh / g, 127.7 mAh / g, and 65.1 mAh / g, respectively. Figure 4 (as shown in b), its charge-discharge curve is as follows: Figure 4 As shown in c.

[0067] Furthermore, we investigated the cycling stability of the three electrode materials at higher rates (0.5C, 1C, 2C). Figure 5As can be seen, the discharge specific capacities exhibited by the Li4C8H2O6 and TCNQ electrodes at 0.5C were 68.4 mAh / g and 115.8 mAh / g, respectively. However, the Li4C8H2O6-TCNQ electrode achieved a discharge specific capacity of 172.1 mAh / g, significantly higher than the former two, which is an advantage brought about by the increased electronic conductivity. At 1C, the Li4C8H2O6, TCNQ, and Li4C8H2O6-TCNQ electrodes exhibited discharge specific capacities of 56.6 mAh / g, 89.3 mAh / g, and 130.4 mAh / g, respectively. Figure 5 b). Under 2C conditions, the Li4C8H2O6, TCNQ, and Li4C8H2O6-TCNQ electrodes exhibited discharge specific capacities of 46.8 mAh / g, 74.2 mAh / g, and 121.7 mAh / g, respectively. Figure 5 c). After 100 cycles, the discharge specific capacity of Li4C8H2O6-TCNQ at all three discharge rates remained higher than that of the two original materials, indicating that the Li4C8H2O6-TCNQ composite material exhibited a clear advantage over the two original materials. Figure 5 As can be seen, at 2C, the discharge plateau of Li4C8H2O6-TCNQ is significantly higher than that of Li4C8H2O6 and TCNQ. This indicates that at high discharge rates, the present invention exhibits more significant electrical performance, and the organic cathode material of the present invention has higher conductivity at high rates; while the comparative examples Li4C8H2O6 and TCNQ show more significant battery polarization. Compared with methods relying on external conductive agents, methods that improve the intrinsic electronic conductivity of organic electrodes have more promising applications.

[0068] In summary, we developed a charge-transfer complex to improve the intrinsic electronic conductivity of Li4C8H2O6 and applied it to solid-state batteries to overcome its low electronic conductivity and solubility tendency in liquid electrolytes. We obtained the charge-transfer complex by combining Li4C8H2O6 with TCNQ at room temperature using 1,3-dioxolane (DOL) as the solvent. Here, Li4C8H2O6 acts as the electron donor, and TCNQ acts as the electron acceptor. Their combination forms an enhanced electron cloud through π-π interactions, establishing an electron transport channel and thus promoting electron transport. The electronic conductivity of the charge-transfer complex Li4C8H2O6-TCNQ reached 7 × 10⁻⁶. -5 The S / cm ratio is 1000 times higher than that of the two original materials; the discharge specific capacity increases to 172 mAh / g at 0.5C, an improvement of about 2 times, and stable cycling at 2C reaches 100. These results demonstrate that charge-transfer complexes offer new development opportunities for the practical application of sulfide-based all-solid-state lithium metal batteries with organic cathodes.

[0069] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

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Claims

1. An organic cathode material with ultra-high electronic conductivity, characterized in that, The organic cathode material is Li4C8H2O6-TCNQ, which is a charge-transfer complex formed by the raw material Li4C8H2O6 and TCNQ.

2. The organic cathode material with ultra-high electronic conductivity according to claim 1, characterized in that, The molar ratio of Li4C8H2O6 to TCNQ in the organic cathode material is (1-2):(1-2).

3. The organic cathode material with ultra-high electronic conductivity according to claim 1, characterized in that, The molar ratio of Li4C8H2O6 to TCNQ in the organic cathode material is 1:

2.

4. The organic cathode material with ultra-high electronic conductivity according to claim 1, characterized in that, The organic cathode material has an electronic conductivity on the order of 10. -5 .

5. An organic cathode material with ultra-high electronic conductivity according to claim 1, characterized in that, The organic cathode material exhibits characteristic peaks at 10.5°, 15.1°, 16.7°, 21.3°, 26.6°, 27.8°, 30.2°, 32.2°, and 38.3° in its X-ray powder diffraction pattern expressed at a diffraction angle of 2θ.

6. A method for preparing the organic cathode material according to any one of claims 1-5, characterized in that, The preparation method includes weighing Li4C8H2O6 and TCNQ according to the molar ratio of Li4C8H2O6 to TCNQ, then adding them to a solvent, stirring, and drying to obtain an organic cathode material.

7. The preparation method according to claim 6, characterized in that, The solvent includes 1,3-dioxolane; the molar ratio of Li4C8H2O6 to TCNQ is (1-2):(1-2).

8. The preparation method according to claim 6, characterized in that, The stirring time is 40-55 hours; the drying temperature is 70-90°C; and the drying time is 10-14 hours.

9. A cathode, characterized in that, The cathode has the organic cathode material according to any one of claims 1-5.

10. The cathode according to claim 9, characterized in that, The cathode also includes a conductive agent and a sulfide solid electrolyte.

11. The cathode according to claim 9, characterized in that, By mass, the organic cathode material accounts for 15%-25% of the total mass of the cathode.

12. The cathode according to claim 10, characterized in that, The conductive agent includes one or more of the following: graphene, conductive carbon black, conductive graphite, carbon fiber, carbon nanotubes, multi-arm carbon nanotubes, Ketjen black, porous carbon, carbon cloth, graphite, hard carbon, coke, soft carbon, acetylene black, carbon whiskers, and needle coke.

13. The cathode according to claim 10, characterized in that, The sulfide solid electrolyte includes one or more of crystalline sulfide solid electrolytes and microcrystalline glassy sulfide solid electrolytes.

14. The cathode according to claim 13, characterized in that, The crystalline sulfide solid electrolyte includes one or more of the following: sulfides with a sulfide-silver-germanium structure and sulfides with a Thio-LiSICON structure.

15. The cathode according to claim 14, characterized in that, The sulfides in the sulfide-silver-germanium ore structure include Li6PS5Cl.

16. The cathode according to claim 14, characterized in that, The sulfides with the Thio-LiSICON structure include Li 10 GeP2S 12 Based on Li 10 GeP2S 12 The sulfide solid electrolyte obtained after element doping.

17. The cathode according to claim 16, characterized in that, The doping elements include one or more of Al, Si, Ga, Sn, N, O, Cl, Br, and I.

18. The cathode according to claim 13, characterized in that, The microcrystalline glassy sulfide solid electrolyte includes one or more of the following: sulfides based on the Li2S-P2S5 system, and multi-component sulfides obtained by elemental doping of sulfides based on the Li2S-P2S5 system.

19. An all-solid-state battery, characterized in that, The all-solid-state battery has the cathode as described in claim 9.

20. The all-solid-state battery according to claim 19, characterized in that, The all-solid-state battery includes sulfide solid-state batteries or halide solid-state batteries.

21. An electrochemical device, characterized in that, The electrochemical device has the cathode as described in claim 9.

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