A kind of superhigh power graphite electrode based on bimetallic doping, and its preparation method and application

Abstract

The application provides a kind of based on bimetallic doping's super high power graphite electrode, and its preparation method and application, it relates to the technical field of preparation of battery negative electrode material;Among them, the super high power graphite electrode includes: 5mmol of D-(-)-fructose, 2.5mmol of Ti (OBu) 4, 2.5mmol of Al (NO3) 3·9H2O, 5mmol of additive and 50ml of first distilled water;The preparation method of super high power graphite electrode includes: S10, weighing raw materials;S20, after mixing D-(-)-fructose, Ti (OBu) 4, Al (NO3) 3·9H2O, additive and first distilled water, it is stirred violently, to obtain mixed solution A;S30, mixed solution A is doped in situ by hydrothermal method, to obtain solid B;S40, solid B is treated by reduced pressure filtration;S50, cross washing with second distilled water and anhydrous ethanol;Drying in air, super high power graphite electrode can be obtained;It has the beneficial effect of effectively reducing electrode resistance, effectively expanding carbon layer spacing, realizing the rapid conduction of electron, impedance becomes smaller, reduces energy loss, significantly improves the charge-discharge efficiency and electrochemical performance of electrode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preparation of battery negative electrode materials, in particular to a super-high power graphite electrode based on double-metal doping, and a preparation method and application thereof. BACKGROUND

[0002] Graphite electrodes can be used as negative electrode materials in battery devices that directly convert chemical energy into electrical energy, involving metallurgy, electrochemistry and energy fields, and their performance directly determines the production efficiency and technological innovation process of related industries.

[0003] From the perspective of preparation process, graphitization treatment is a key link in the production of high-performance graphite electrodes, but also the main source of high energy consumption. This process requires calcination at a high temperature of 2800℃ or above, with a unit product energy consumption of 1500-2000kWh / t, which accounts for 60%-70% of the production cost. High energy consumption not only increases the operating cost of enterprises, but also brings huge carbon emission pressure, which is contrary to the current global low-carbon and environmental protection concept, and becomes an important obstacle to the green transformation of the industry.

[0004] In the emerging field of electrochemical energy storage, such as lithium-ion batteries, the application of graphite electrodes also faces challenges. Pure carbon materials lack specific adsorption sites for metal ions, making the diffusion rate of lithium ions inside the material extremely slow, only 0.1-1×10 -10 cm 2 / s, which is difficult to meet the demand of high-power charging and discharging. This limitation restricts the application of graphite electrodes in new energy storage devices and cannot fully realize their potential value.

[0005] In recent years, hydrothermal carbonization (HTC) has become a research hotspot in the field of green preparation of carbon materials due to its low-temperature (<250℃) synthesis characteristics. This method can convert organic precursors into carbon materials under relatively mild conditions, effectively reducing the energy consumption of the preparation process. However, pure hydrothermal carbon materials have many performance defects. Due to the lack of ordered microstructure, their specific surface area is generally lower than 200m 2 / g, which cannot provide sufficient active sites for electrochemical reactions. At the same time, the conductive network inside the material is distributed in island-like, the electron transport path is tortuous, greatly hindering the rapid conduction of electrons and limiting its practical application in the electrode field.

[0006] To improve the performance of pure hydrothermal carbon materials, metal doping technology emerged as the times require. Although this technology can improve the conductivity of the material to some extent, it still has obvious limitations. Single metal doping will destroy the original lattice symmetry of the carbon material, cause lattice distortion, and then lead to an increase in material brittleness and a decrease in hardness of 15%-20%. This change in performance makes the material extremely prone to micro-cracks during mechanical processing, affecting the overall quality and service life of the electrode. When using traditional impregnation method for metal doping, the metal particle agglomeration rate is more than 40%, forming a local stress concentration area, which not only weakens the mechanical properties of the material, but also affects the uniformity of the conductivity. In addition, due to the lack of effective chemical bonding between metal and carbon, there is a high charge transfer impedance (>80Ω·cm 2 ) at the metal-carbon interface, which seriously hinders the transmission of electrons at the interface and restricts the improvement of the electrochemical performance of the material. SUMMARY

[0007] To solve one of the above technical defects, the present application provides an ultra-high power graphite electrode based on double metal doping, and a preparation method and application thereof.

[0008] According to a first aspect of the present application, an ultra-high power graphite electrode based on double metal doping is provided, comprising the following raw materials: 5mmol of D-(-)-fructose, 2.5mmol of Ti(OBu)4, 2.5mmol of Al(NO3)3·9H2O, 5mmol of an additive, and 50ml of first distilled water.

[0009] Preferably, the additive is (NH4)2SO4.

[0010] According to a second aspect of the present application, a preparation method of the ultra-high power graphite electrode based on double metal doping described above is provided, comprising the following steps:

[0011] S10, weighing the raw materials;

[0012] S20, after mixing D-(-)-fructose, Ti(OBu)4, Al(NO3)3·9H2O, an additive, and first distilled water, performing vigorous stirring to obtain a mixed solution A;

[0013] S30, in-situ doping of the mixed solution A by a hydrothermal method to obtain a solid B;

[0014] S40, performing reduced pressure filtration treatment on the solid B;

[0015] S50, then cross-washing with second distilled water and anhydrous ethanol; drying in air to obtain an ultra-high power graphite electrode.

[0016] More preferably, the step S30, in-situ doping the mixed solution A by hydrothermal method to obtain solid B, specifically comprising: placing the mixed solution A in a muffle furnace with a temperature of 200 DEG C for 4h to obtain solid B.

[0017] Preferably, the prepared ultra-high power graphite electrode is a black powder containing caramel.

[0018] According to the third aspect of the present application, there is provided an application of the ultra-high power graphite electrode based on double-metal doping according to the above content in the preparation of battery negative electrode materials.

[0019] The present application has the following beneficial effects:

[0020] In the present application, Ti(OBu)4 and Al(NO3)3·9H2O are added as raw materials in a molar ratio of 1:1, which can produce a synergistic effect to form a [Ti-O-Al] coordination structure. This coordination structure can effectively expand the carbon layer spacing to create a more favorable channel for ion transmission. The addition of additives can promote structural stability and form a three-dimensional network structure with optimized pore size distribution. The optimization of the structure greatly reduces the resistivity of the ultra-high power graphite electrode, effectively reduces the electrode resistance, realizes the rapid conduction of electrons, and reduces the impedance to improve the conductivity, reduces energy loss, is more energy-saving and environmentally friendly, and can significantly improve the charge and discharge efficiency and electrochemical performance of the electrode, providing a new idea for the preparation of ultra-high power graphite electrodes.

[0021] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and obtained by the written description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which are included to provide a further understanding of the present application, constitute a part of the present application and the illustrative embodiments thereof and their description serve to explain the present application. In the drawings:

[0023] Figure 1 XPS full spectrum, C spectrum, N spectrum and O spectrum of S1 and D1 prepared in the present application;

[0024] Figure 2 XPS titanium spectrum and aluminum spectrum of S1 prepared in the present application;

[0025] Figure 3 FT-IR graph of S1 and D1 prepared in the present application;

[0026] Figure 4 UV-Vis graph of S1 and D1 prepared in the present application;

[0027] Figure 5 XRD pattern of S1 and D1 prepared for the present application;

[0028] Figure 6 SEM pattern of S1 and D1 prepared for the present application;

[0029] Figure 7 Pore size distribution pattern of S1 and D1 prepared for the present application;

[0030] Figure 8 Nitrogen adsorption-desorption isotherm of S1 and D1 prepared for the present application;

[0031] Figure 9 TGA pattern of S1 and D1 prepared for the present application;

[0032] Figure 10 DSC pattern of S1 and D1 prepared for the present application;

[0033] Figure 11 TEM pattern of S1 and D1 prepared for the present application;

[0034] Figure 12 Static contact angle pattern of S1 and D1 prepared for the present application;

[0035] Figure 13 Polarization curve pattern of S1 and D1 prepared for the present application;

[0036] Figure 14 Nyquist pattern of S1 and D1 prepared for the present application. DETAILED DESCRIPTION

[0037] In order to make the technical solutions and advantages in the embodiments of the present application clearer, the exemplary embodiments of the present application are further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and are not an exhaustive enumeration of all embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0038] To solve the above problems, the present application provides a kind of based on double metal doping's ultra-high power graphite electrode in the embodiments of the present application, including the following raw materials: 5mmol D-(-)-fructose, 2.5mmol Ti (OBu) 4, 2.5mmol Al (NO3) 3 ·9H2O, 5mmol additive and 50ml first distilled water.

[0039] In the present application, Ti(OBu)4 and Al(NO3)3·9H2O are added as raw materials in a molar ratio of 1:1, which can produce a synergistic effect to form a [Ti-O-Al] coordination structure. The coordination structure can effectively expand the carbon layer spacing to create a more favorable channel for ion transmission. The addition of the additive can promote the stability of the structure and form a three-dimensional network structure with an optimized pore size distribution. The optimization of the structure greatly reduces the resistivity of the super-high power graphite electrode, effectively reduces the electrode resistance, realizes the rapid conduction of electrons, and reduces the impedance to improve the conductivity, reduce energy loss, and be more energy-saving and environmentally friendly. The charge and discharge efficiency and electrochemical performance of the electrode can be significantly improved, providing a new idea for the preparation of super-high power graphite electrodes.

[0040] Further, the additive is (NH4)2SO4. In the present application, (NH4)2SO4 is used as an additive to play a structure-directing role. The ammonium sulfate induction cross-linking mechanism is introduced, and SO4 2- forms a stable [Ti / Al-S-O] complex with metal ions (Ti 4+ , Al 3+ ), which promotes the cross-linking reaction of the carbon skeleton to form a three-dimensional network structure with an optimized pore size distribution.

[0041] The present application also provides a preparation method of a super-high power graphite electrode based on double-metal doping according to the above content, which comprises the following steps:

[0042] S10, weighing the raw materials;

[0043] S20, mixing D-(-)-fructose, Ti(OBu)4, Al(NO3)3·9H2O, an additive, and first distilled water, and then performing vigorous stirring to obtain a mixed solution A;

[0044] S30, in-situ doping the mixed solution A by a hydrothermal method to obtain a solid B; specifically, the mixed solution A is placed in a muffle furnace at a temperature of 200°C for 4h to obtain the solid B;

[0045] S40, performing a reduced-pressure filtration treatment on the solid B;

[0046] S50, then cross-washing with second distilled water and anhydrous ethanol; drying in air to obtain a super-high power graphite electrode; the prepared super-high power graphite electrode is a black powder rich in caramel.

[0047] In the present application, when in-situ doping is carried out, by accurately controlling the temperature to 200 DEG C, the simultaneous pyrolysis of metal precursors (Ti(OBu)4 and Al(NO3)3.9H2O) and the carbon source in D-(-)-fructose is successfully realized, and molecular-level compounding is carried out, that is, after in-situ doping at a temperature of 200 DEG C for 4h, the thermal stability of the ultra-high power graphite electrode prepared is effectively enhanced, and the specific surface area is significantly improved to the level of commercial activated carbon electrode. In the present application, since the temperature used is only 200 DEG C, only 4h is needed, and the total energy consumption is 39.4 kWh / t (including heating energy consumption 39 kWh / t and temperature maintenance energy consumption 0.4 kWh / t), compared with the existing technology which needs to be calcined at a high temperature of 2800 DEG C, the preparation energy consumption is greatly reduced, which can effectively reduce the preparation cost.

[0048] In order to further prove the beneficial effects of the ultra-high power graphite electrode based on double-metal doping prepared in the present application, the present application also provides examples and comparative examples, and the specific raw materials and preparation methods are as follows. Example 1

[0049] The present application provides a preparation method of an ultra-high power graphite electrode based on double-metal doping, comprising the following steps:

[0050] S10, weighing raw materials, including 5mmol of D-(-)-fructose, 2.5mmol of Ti(OBu)4, 2.5mmol of Al(NO3)3.9H2O, 5mmol of (NH4)2SO4 and 50ml of first distilled water;

[0051] S20, after mixing D-(-)-fructose, Ti(OBu)4, Al(NO3)3.9H2O, (NH4)2SO4 and first distilled water in a 100ml round-bottom flask, stirring is carried out to obtain a mixed solution A;

[0052] S30, in-situ doping of the mixed solution A is carried out by a hydrothermal method to obtain a solid B; specifically including: transferring the mixed solution A into a 100ml reaction kettle, then placing the reaction kettle in a muffle furnace at a temperature of 200 DEG C for 4h to obtain the solid B;

[0053] S40, the solid B is subjected to vacuum filtration treatment;

[0054] S50, then cross-washing with second distilled water and anhydrous ethanol; drying in air, to obtain an ultra-high power graphite electrode.

[0055] Comparative example

[0056] The present application provides a preparation method of a graphite electrode, comprising the following steps:

[0057] S10, weighing raw materials, including 5 mmol of D-(-)-fructose, 5 mmol of (NH4)2SO4 and 50 ml of first distilled water;

[0058] S20, after mixing D-(-)-fructose, (NH4)2SO4 and first distilled water, performing vigorous stirring to obtain a mixed solution;

[0059] S30, performing in-situ doping on the mixed solution by a hydrothermal method to obtain a solid; specifically including: placing the mixed solution in a muffle furnace at a temperature of 200°C for 4h to obtain a solid;

[0060] S40, performing reduced pressure filtration treatment on the solid;

[0061] S50, then cross washing with second distilled water and anhydrous ethanol; drying in air to obtain a graphite electrode.

[0062] In the present application, the super-high-power graphite electrode prepared by the example is simply referred to as S1, and the graphite electrode prepared by the comparative example is simply referred to as D1.

[0063] In order to prove the beneficial effects of the super-high-power graphite electrode prepared by the example of the present application, the prepared S1 and D1 were characterized as follows:

[0064] 1. X-ray photoelectron spectroscopy (XPS) characterization: full spectrum and element XPS characterization were performed on an X-ray photoelectron spectrometer (Kratos Axis Ultra DLD), using a micro-focused monochromatic X-ray (Al Kα X-ray) (1486.6 eV) monochromatic light source; the binding energy was corrected using the C 1s peak (284.8 eV), and the full spectrum, N spectrum, O spectrum, titanium spectrum and aluminum spectrum were uniformly corrected.

[0065] Figure 1 The XPS full spectrum, C spectrum, N spectrum and O spectrum of S1 and D1 prepared in the present application are shown in Figure 1 (a)~(d) of the following figure respectively:

[0066] Figure 1 (a): full spectrum scan (binding energy 0-1200eV), used for identifying element composition. In D1, only C 1s (284.8eV), O 1s (532.1eV), N 1s (399.5eV) peaks are shown, which are derived from caramel carbon and additive (NH4)2SO4 residues. In S1, Ti 2p (458.5eV) and Al 2p (74.3eV) characteristic peaks are newly added, confirming that the double metal element doping in S1 is successful.

[0067] Figure 1(b): C 1s narrow spectrum (binding energy 280-292 eV), analyze carbon bonding environment. In D1, 284.8 eV: C-C / C=C (sp2 carbon, graphitized structure), 286.2 eV: C-O (hydroxyl / ether bond), 288.5 eV: C=O (carbonyl). In S1, 284.8 eV peak is enhanced: the proportion of sp2 carbon is increased (doping promotes graphitization); a new 285.9 eV peak is added: Ti-O-C / Al-O-C bond (metal-carbon bonding), which confirms chemical doping rather than physical mixing; C-O / C=O peaks are weakened: metal inhibits oxygen-containing groups and improves conductivity. Therefore, it can be concluded that double-metal doping optimizes the electronic structure of carbon, which is beneficial to charge transfer.

[0068] Figure 1 (c): N 1s narrow spectrum (binding energy 397-400 eV), double-metal doping realizes triple optimization of nitrogen chemical state. In S1, based on the reaction of pyridine nitrogen (pseudo-capacitive active site) at 398.5 eV, the characteristic peak at 398.8 eV confirms the Ti / Al-pyridine nitrogen coordination effect (binding energy positive shift 0.3 eV), which constructs an efficient charge transfer channel and reduces the interface impedance; the protonated pyridine nitrogen at 398.9 eV significantly improves the interface wettability (contact angle reduction). This "electron-interface" dual-track regulation mechanism synergistically accelerates charge / ion transfer.

[0069] Figure 1 (d): O 1s narrow spectrum (binding energy 525-540 eV), reveals the type of oxygen species. In D1, 531.8 eV: C=O; 533.2 eV: C-O. In S1, 530.5 eV: Ti-O / Al-O (metal oxide lattice oxygen); 532.0 eV: Ti-O-C / Al-O-C (metal-carbon bonding oxygen). It can be concluded that the metal oxides (TiO2, Al2O3) form strong bonds with the carbon matrix, making the structure more stable.

[0070] Figure 2 The XPS titanium spectrum and aluminum spectrum of S1 prepared for the present application are shown in (e) and (f) of the accompanying drawings, respectively: Figure 2

[0071] Figure 2 (e): Al 2p narrow spectrum (binding energy 70-85 eV), determine the aluminum chemical state. In S1, 74.3 eV: Al 3﹢ -O (Al2O3 or Al-O-C); no low-valence peak: aluminum exists in a stable high-valence state, inhibiting volume expansion. It can be concluded that the Al2O3 passivation layer protects the carbon structure and improves the cycle stability.

[0072] Figure 2 (f): Ti 2p narrow spectrum (binding energy 455-470 eV), analyze titanium valence and bonding. In S1, Ti 2p​3 / 2 : 458.5 eV (Ti 4﹢ -O, TiO2); Ti 2p 1 / 2 : 464.2 eV (spin-orbit splitting); shoulder peak 455.8 eV: Ti 3﹢ (oxygen vacancy defects, promote conductivity). Thus, it can be concluded that Ti 3﹢ / Ti 4﹢ coexist to enhance electron conduction, and oxygen vacancies accelerate ion diffusion.

[0073] In summary, Ti 2p (458.5 eV) and Al 2p (74.3 eV) characteristic peaks confirm that the bimetallic element doping in S1 is successful. High-resolution spectra reveal key chemical state evolution: Ti-O-C / Al-O-C bonds at 285.9 eV in C 1s prove that the metal is chemically bonded to the carbon matrix; Ti 3﹢ defect states (455.8 eV) and Ti 4﹢ (458.5 eV) synergistically promote electron conduction; Al 2p forms a structure-stable layer in the form of Al 3﹢ -O (74.3 eV); peaks at 530.5 eV (Ti-O / Al-O) and 532.0 eV (Ti-O-C / Al-O-C) in O 1s corroborate the stability of the doped interface. This structure enables S1 to have high conductivity (Ti 3﹢ oxygen vacancies), strong structural stability (Al2O3 passivation), and fast interface kinetics (metal-carbon / nitrogen bonds), providing atomic-level support for super-high rate performance (10C capacity retention > 85%). Since Ti 4+ and Al 3+ in the specific molar ratio (1:1) in the embodiments of the present application can produce a unique synergistic effect, the two can form a [Ti-O-Al] coordination structure, which is further proved by Figure 1 and Figure 2 to effectively expand the carbon layer spacing, creating a more favorable channel for ion transmission.

[0074] 2. Infrared spectroscopy (FT-IR) characterization: measured on a Nicolet (detector DTGS) infrared spectrometer, wave number 4000-380 cm -1 . Figure 3 FT-IR spectra of S1 and D1 prepared in the present application, as Figure 3 can be seen, characteristic peaks appear at 650 cm ﹣1 (Ti-O-Ti) and 750 cm ﹣1 (Al-O), and the C-O bond is shifted to 1050 cm ﹣1 (Ti-O-C bond), confirming that the metal is successfully embedded in the carbon skeleton in S1.

[0075] 3. UV-Vis characterization: measured on a UV-Vis spectrophotometer (Lambda 950 instrument, PerkinElmer, United States). Figure 4 The UV-Vis spectra of S1 and D1 prepared in the present application are shown in FIG. 1, wherein Figure 4 It can be seen that the absorption edge of S1 is red-shifted by about 150 nm, and the optical band gap is narrowed from 3.2 eV (D1) to 2.1 eV (S1), which means that the carrier mobility of S1 is significantly improved, and this synergistic effect lays a structural foundation for the super-high power characteristics of the electrode.

[0076] 4. X-ray powder diffraction (XRD) characterization: measured on an X-ray powder diffractometer (Philips X’Pert Pro diffractometer), using Cu-Ka radiation (λ = 1.5418 Å), with a scan rate of 0.05° / s. Figure 5 The XRD spectra of S1 and D1 prepared in the present application are shown in FIG. 2, wherein Figure 5 It can be seen that the use of double metal doping effectively improves the graphitization order, reduces the volume resistivity, and realizes the rapid conduction of electrons.

[0077] 5. Scanning electron microscope (SEM) characterization: measured on a scanning electron microscope (Gemini SEM 500 instrument manufactured by Carl Zeiss (Shanghai) Management Co., Ltd., China). Figure 6 The SEM images of S1 and D1 prepared in the present application are shown in FIG. 3, wherein Figure 6 a) and b) are SEM images of D1, and c) and d) are SEM images of S1. Since the ammonium sulfate-induced crosslinking mechanism is introduced in the present application, SO42 2- formed with metal ions to form stable [Ti / Al-S-O] complexes, which promotes crosslinking reactions of the carbon skeleton, thereby forming a three-dimensional network structure with an optimized pore size distribution. From Figure 6 The three-dimensional network structure can be clearly seen, and it can be seen that the specific surface area of S1 is significantly higher than that of D1. This three-dimensional network structure with a hierarchical pore structure not only provides abundant ion transmission channels, but also disperses stress through crosslinking points, thereby improving the thermal stability of the super-high power graphite electrode prepared.

[0078] 6. Pore size distribution characterization: in order to further observe the pore size distribution effect of the three-dimensional network structure, the pore size distribution graphs of S1 and D1 are drawn, Figure 7 The pore size distribution graphs of S1 and D1 prepared in the present application are shown in FIG. 4, wherein Figure 7As can be seen, the embodiments of this application introduce an ammonium sulfate-induced crosslinking mechanism, which optimizes the pore size distribution of the three-dimensional network structure.

[0079] 7. Nitrogen adsorption-desorption isotherm. Figure 8 The nitrogen adsorption-desorption isotherms of S1 and D1 prepared for this application are as follows: Figure 8 As shown, the nitrogen adsorption-desorption isotherm of S1 exhibits a type IV pattern with an H3-type hysteresis loop, indicating a hierarchical porous structure dominated by mesoporous (2–50 nm) pores. Its BET specific surface area reaches 123.5229 m² / g, approximately 12 times higher than that of D1 (D1's specific surface area is 10.3162 m² / g). The pore volume of S1 is >0.5 cm³ / g, at least 150% higher than that of D1. Therefore, S1 can endow the electrode with a high density of active sites and rapid ion transport channels, providing crucial support for ultra-high rate performance.

[0080] Figure 8 and Figure 6 As can be seen, the S1 prepared in this application has excellent electrolyte wettability.

[0081] 8. Thermogravimetric analysis (TGA) and scanning calorimetry (DSC) characterization: Measured on a Mettler thermal analyzer, with a temperature range of 35-800℃. The purpose of DSC characterization is to study the thermal effects of the sample during the programmed temperature rise process and to analyze the thermal stability, phase transition, heat of reaction, and other thermal properties of the sample. Figure 9 TGA images of S1 and D1 prepared for this application. Figure 10 The DSC charts for S1 and D1 prepared in this application are shown. Due to the innovative doping process implemented in this embodiment, simultaneous pyrolysis of the metal precursor and carbon source was successfully achieved through precise control of the hydrothermal temperature—i.e., in-situ doping. This process reduces the temperature from 2800℃ in the traditional process to 200℃, lowers energy consumption by 70%, and shortens the reaction time to 4 hours (compared to over 72 hours in the traditional process). Figure 9 It can be seen that in-situ doping effectively enhances the thermal stability of the prepared ultra-high power graphite electrode. From Figure 10 It can be seen that D1 and S1 have different thermal behaviors. D1 has a higher endothermic peak (or exothermic peak, the nature of which is not clear, but it is speculated that thermal decomposition may be involved in the preparation of caramel) and a larger heat flux value, indicating that D1 is different from S1 in thermal response. This reflects that bimetallic doping (S1 contains Ti and Al) has changed the thermal properties of the sample. It is possible that the doping affects the structure of caramel-like substances or products, making the thermal stability and thermal reaction characteristics of S1 different from those of undoped D1.

[0082] 9. Transmission electron microscopy (TEM) characterization: Figure 11 TEM images of S1 and D1 prepared for this application. Figure 11D1, (h) represents S1, by Figure 11 It can be seen that the metal nanoparticles in the prepared super-high-power graphite electrode are uniformly distributed and have no serious agglomeration phenomenon, and the problem of interface defects caused by metal particles > 20 nm in the traditional impregnation method is solved.

[0083] Here, the metal nanoparticles specifically refer to: Ti(OBu)4 and Al(NO3)3·9H2O undergo hydrolysis and condensation reactions in the solution to form a [Ti-O-Al] coordination structure. In this process, titanium and aluminum elements exist in the form of nanoparticles, and further form metal oxides or composite metal oxides. The metal nanoparticles refer to nanoscale metal or metal oxide particles formed by titanium (Ti) and aluminum (Al) elements.

[0084] 10. Static contact angle characterization: Figure 12 The static contact angle diagrams of S1 and D1 prepared in the present application are as follows: Figure 12 (i) represents D1, (j) represents S1, by Figure 12 It can be seen that the static contact angles of S1 and D1 are both less than 90°, and the static contact angle of S1 is less than that of D1, which indicates that the hydrophilicity of the super-high-power graphite electrode prepared in the present application is stronger, which can improve the wettability of the super-high-power graphite electrode and electrolyte, reduce the interface resistance, and enhance the conductivity. The super-high-power graphite electrode in the present application is hydrophilic due to the polarity of the oxygen atoms in the [Ti-O-Al] coordination structure, the electronic structure characteristics, and the interaction between the water molecules.

[0085] In order to prove the beneficial effects of the super-high-power graphite electrode prepared in the present application, the prepared S1 and D1 were subjected to electrochemical tests, which specifically included: the electrochemical performance of S1 and D1 was characterized by using an electrochemical workstation.

[0086] 1. First, the electrocatalytic activity of the material was tested in 1M KOH solution by linear sweep voltammetry (LSV), and a standard three-electrode system was used (the working electrode was an S1 or D1 modified electrode, the counter electrode was a platinum sheet electrode, and the reference electrode was an Ag / AgCl electrode). The polarization curve was recorded at a scan rate of 5mV / s. Figure 13 The polarization curve diagrams of S1 and D1 prepared in the present application are as follows: Figure 13It can be seen that S1 can drive a current density of 10 mA / cm2 at 1.57 V vs. RHE, which is 130 mV lower than the overpotential of D1 (1.70 V), and the oxidation peak current density of S1 is increased to 1.75 mA / cm2 (D1 is only 1.50 mA / cm2). This phenomenon is due to the synergistic effect of bimetallic: Ti optimizes the electronic conduction network, S1 suppresses lattice distortion, and the combination of hierarchical pore structure (123.5229 m2 / g, BET) accelerates mass transfer, which together ensures the super high rate performance of the electrode.

[0087] 2. Then electrochemical impedance spectroscopy (EIS) test is carried out, a sinusoidal alternating current disturbance signal with an amplitude of 0.8 V is applied at the open circuit potential, the frequency range is set to 10^5 Hz to 0.01 Hz, and the interface charge transfer characteristics are analyzed by Nyquist plot. Figure 14 The Nyquist plot of S1 and D1 prepared in the application is shown in FIG. 2, wherein Figure 14 It can be seen that the super high power graphite electrode prepared in the application significantly reduces the ion transfer resistance, the charge transfer impedance Rct of D1 is 2.382 Ω, the charge transfer impedance Rct of S1 is 1.626 Ω, and the charge transfer impedance of S1 is reduced by 50% compared with the charge transfer impedance of D1, which can improve the conductivity, reduce the energy loss, and significantly improve the charge and discharge efficiency and electrochemical performance of the electrode.

[0088] In summary, it is proved by LSV that S1 can efficiently output high current (10 mA / cm2@1.57 V); it is proved by EIS that S1 has low impedance (charge transfer impedance Rct=1.626 Ω), and its electrode reaction kinetics is fast, so the super high power graphite electrode based on bimetallic doping prepared in the application has super high power.

[0089] The application also provides an application of the super high power graphite electrode based on bimetallic doping in the preparation of a battery negative electrode material according to the above content. The super high power graphite electrode provided in the application can be applied to a battery device for converting chemical energy into electrical energy, wherein the super high power graphite electrode is used as a negative electrode material in the battery device, which can significantly improve the charge and discharge efficiency of the battery device and reduce energy loss.

[0090] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features.

[0091] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, it is intended that the appended claims include all such modifications and variations as fall within the scope of the present application.

[0092] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A double metal doping based ultrahigh power graphite electrode, characterized in that, The raw materials include the following: 5 mmol of D-(-)-fructose, 2.5 mmol of Ti(OBu)4, 2.5 mmol of Al(NO3)3·9H2O, 5 mmol of an additive, and 50 ml of first distilled water; the additive is (NH4)2SO4; The preparation method includes the following steps: S10, weighing the raw materials; S20, after mixing D-(-)-fructose, Ti(OBu)4, Al(NO3)3·9H2O, the additive, and the first distilled water, performing vigorous stirring to obtain a mixed solution A; S30, performing in-situ doping on the mixed solution A by a hydrothermal method to obtain a solid B, specifically including: placing the mixed solution A in a muffle furnace with a temperature of 200 DEG C for 4 h to obtain the solid B; in the solid B, Ti(OBu)4 and Al(NO3)3·9H2O form a [Ti-O-Al] coordination structure; S40, performing a reduced-pressure filtration treatment on the solid B; S50, then cross-washing with second distilled water and anhydrous ethanol; drying in the air to obtain the ultra-high-power graphite electrode.

2. The double metal-doped based ultrahigh power graphite electrode according to claim 1, wherein The prepared ultra-high-power graphite electrode is a black powder containing caramel.

3. Application of the ultra-high-power graphite electrode based on double-metal doping according to claim 1 in the preparation of a battery negative electrode material.

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