Biomass derived carbon material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of battery negative electrode materials, and discloses a biomass derived carbon material as well as a preparation method and application thereof. The surface of the biomass derived carbon material is loaded with nano-clusters or nano-particles of a metal simple substance or a metal compound. The preparation method comprises the following steps: mixing a biomass precursor and a metal salt, and carrying out one-step pyrolysis to obtain the biomass derived carbon material. The biomass derived carbon material can be used as an alkali metal ion battery negative electrode material. Through the unique technical means of loading the metal simple substance / metal compound with the nano-cluster or nano-particle form on the surface of the biomass charcoal, the fast charging performance of the negative electrode material is practically and effectively improved. The battery prepared from the negative electrode material shows excellent comprehensive performance, and has excellent key performance indexes such as charge-discharge efficiency, cycle stability and energy density.

Description

Technical Field

[0001] The present invention relates to the technical field of battery anode materials, and particularly to a biomass-derived carbon material, a preparation method thereof, and an application thereof. Background Art

[0002] Alkali metal ion batteries have been widely used in fields such as electric vehicles and portable electronic devices due to their advantages such as high energy density and long cycle life. However, with the improvement of living standards, people have put forward higher requirements for the fast charging performance of electronic devices. The fast charging characteristics of batteries mainly depend on the anode material, and there are still obvious deficiencies in the fast charging performance of existing anode materials. Under fast charging conditions, various polarizations inside the battery will cause the precipitation of alkali metals on the anode surface, which will not only cause irreversible capacity loss of the battery, reduce the overall capacity and cycle life, but also may further form alkali metal dendrites. The growth of dendrites may cause internal short circuits in the battery, and in severe cases, it may lead to safety accidents such as rapid heating, ignition, and even explosion of the battery. Especially in the case of a limited N / P ratio, this situation is more serious. Therefore, the development of high-performance fast-charging anode materials is of great significance for promoting the large-scale application of alkali metal ion batteries.

[0003] Biomass has become an ideal precursor for preparing fast-charging anode materials for alkali metal ion batteries due to its natural morphological structure and chemical composition. When the biomass carbon prepared by pyrolysis is used as the anode of an alkali metal ion battery, it can provide abundant reaction sites for storing alkali metal ions. However, current biomass carbon anode materials still face many challenges in practical applications: their capacity for storing alkali metals is generally low, the Coulomb efficiency of the first cycle is not ideal, especially under fast charging conditions, the precipitation of alkali metals on the anode surface leads to low reversible capacity and limited cycle life, and it may further form alkali metal dendrites, triggering safety accidents, and it is difficult to meet the actual needs. Metal elements and metal compounds have good alkali metal affinity, can effectively reduce the desolvation energy barrier of alkali metal ions, accelerate the rapid diffusion of alkali metal ions on the anode surface, can also provide additional capacity, and inhibit the precipitation of alkali metals and the formation of dendrites. Applying them to the anode material can significantly improve the fast charging performance of the anode material. Therefore, designing a simple and efficient scheme to achieve the uniform loading of metal elements or metal compounds on the surface of biomass carbon, so as to prepare a fast-charging anode material, is of great significance for promoting the large-scale application of alkali metal ion batteries. Summary of the Invention

[0004] The present invention aims to solve the technical problems that the reversible capacity of the whole battery is low and the cycle life is limited due to the precipitation of alkali metals on the anode surface under fast charging and limited N / P conditions of existing alkali metal ion battery anode materials, and provides a biomass-derived carbon material, a preparation method thereof, and an application thereof.

[0005] In the present invention, the fast charging condition means charging the battery to 80% at a rate of 4C; the limited N / P means the N / P ratio is 1 - 2, or 1 - 1.5.

[0006] To achieve the above object, a first aspect of the present invention provides a biomass-derived carbon material, wherein nano-clusters or nano-particles of a metal element or a metal compound are loaded on the surface of the biomass-derived carbon material.

[0007] A second aspect of the present invention provides a preparation method of the biomass-derived carbon material according to the first aspect, wherein the method includes: mixing a biomass precursor and a metal salt and then performing one-step pyrolysis to obtain the biomass-derived carbon material.

[0008] A third aspect of the present invention provides the biomass-derived carbon material obtained by the preparation method described in the second aspect.

[0009] A fourth aspect of the present invention provides the application of the biomass-derived carbon material described in the first aspect or the third aspect as a negative electrode material for an alkali metal ion battery.

[0010] A fifth aspect of the present invention provides an alkali metal ion battery, wherein the alkali metal ion battery uses the biomass-derived carbon material described in the first aspect or the third aspect as a negative electrode material.

[0011] Through the above technical solutions, the beneficial technical effects obtained by the present invention are as follows:

[0012] (1) For the metal element or metal compound loaded in the biomass-derived carbon material provided by the present invention, when the loading amount is relatively low, its size is smaller and the dispersibility is better.

[0013] (2) By the unique technical means of loading metal elements / metal compounds in the form of nano-clusters or nano-particles on the surface of biomass carbon, the present invention effectively improves the fast charging performance of the negative electrode material. Through test verification, the battery made of this negative electrode material shows excellent comprehensive performance, and performs outstandingly in key performance indicators such as charge and discharge efficiency, cycle stability, and energy density. This makes the battery have extremely broad research and application prospects in actual battery application fields such as electric vehicles and mobile electronic devices.

[0014] (3) The preparation method provided by the present invention has remarkable simplicity, and the preparation conditions are mild and easy to accurately control. Description of the Drawings

[0015] Figure 1 is the TEM image of the cellulose-derived carbon material prepared in Example 1 of the present invention.

[0016] Figure 2XRD pattern of the cellulose-derived carbon material prepared in Example 1 of the present invention

[0017] Figure 3 Raman spectrum of the cellulose-derived carbon material prepared in Example 1 of the present invention.

[0018] Figure 4 Comparison chart of the cycling performance of the carbon materials prepared in Example 1 and Comparative Examples 1-2 of the present invention in a sodium-ion half-cell.

[0019] Figure 5 Comparison chart of the long-term cycling performance of the carbon materials prepared in Example 1 and Comparative Examples 1-2 of the present invention in a sodium-ion full cell. Detailed implementation manners

[0020] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0021] The first aspect of the present invention provides a biomass-derived carbon material, wherein nanoclusters or nanoparticles of a metal element or a metal compound are loaded on the surface of the biomass-derived carbon material.

[0022] The biomass-derived carbon material provided by the present invention is uniformly loaded with nanoclusters or nanoparticles of a metal element or a metal compound on its surface. When used as the negative electrode material of an alkali metal ion battery, it can significantly improve the reversible capacity and cycle life of the alkali metal ion battery under fast charging and limited N / P conditions. During the charge and discharge process, the metal element or metal compound has good alkali metal affinity, can effectively reduce the desolvation energy barrier of alkali metal ions, accelerate the rapid diffusion of alkali metal ions on the surface of the negative electrode, and can also provide additional capacity and inhibit the precipitation of alkali metal and the formation of dendrites. In the present invention, the existence of the metal element or metal compound in the form of nanoclusters or nanoparticles can provide more reaction sites, significantly shorten the ion diffusion distance, and show a small volume change during the charge and discharge process, which helps to maintain the stability of the electrode structure. At the same time, the nanoclusters or nanoparticles in this form form a tight interfacial contact with the biomass carbon matrix, effectively reducing the interfacial resistance and improving the electron conduction efficiency.

[0023] In some embodiments of the present invention, the loading amount of the elemental metal or metal compound is 1-50 wt%, such as 1 wt%, 5.24 wt%, 5.84 wt%, 5.93 wt%, 6.17 wt%, 6.79 wt%, 8.51 wt%, 8.54 wt%, 8.75 wt%, 12.43 wt%, 27.64 wt%, 35 wt%, 50 wt%, and any value within the range composed of any two of the above values. Preferably, it is 5-40 wt%, and more preferably 5.24-27.64 wt%.

[0024] In some embodiments of the present invention, the diameter of the nanoclusters is 1-10 nm, preferably 1-4 nm, or 1-2 nm, or 2-4 nm, or 3-4 nm.

[0025] In some embodiments of the present invention, the diameter of the nanoparticles is 1-100 nm, preferably 10-100 nm, more preferably 2-30 nm, or 12-18 nm, or 32-78 nm, or 15-24 nm, or 2-4 nm.

[0026] In some embodiments of the present invention, the biomass-derived carbon material uses a biomass precursor selected from at least one of cellulose, chitosan, starch, collagen, tannic acid, lignin, and oxalic acid. Preferably, it is at least one of sulfonated cellulose, sulfonated starch, sulfonated tannic acid, and phosphated cellulose.

[0027] In some embodiments of the present invention, the biomass precursor used for the biomass-derived carbon material contains functional groups, and the functional groups are selected from at least one of sulfonic acid group (-SO 3 H), phosphoric acid group (-PO 4 3- ), amino group (-NH 2 ), carboxyl group (-COOH), hydroxyl group (-OH), mercapto group (-SH), nitro group (-NO 2 ), and pyridyl group (C 5 H 4 N-). Preferably, it is sulfonic acid group and / or phosphoric acid group.

[0028] In some embodiments of the present invention, the elemental metal or metal compound is selected from at least one of elemental tin, tin oxide, tin sulfide, elemental copper, copper oxide, copper sulfide, copper phosphide, elemental iron, iron oxide, iron sulfide, iron phosphide, elemental zinc, zinc oxide, zinc sulfide, zinc phosphide, elemental cobalt, cobalt oxide, cobalt sulfide, cobalt phosphide, elemental manganese, manganese oxide, manganese sulfide, manganese phosphide, elemental nickel, nickel oxide, nickel sulfide, nickel phosphide, elemental chromium, chromium oxide, chromium sulfide, chromium phosphide, cadmium oxide, cadmium sulfide, elemental silver, elemental lead, lead oxide, lead sulfide and lead phosphide, preferably at least one of elemental tin, elemental zinc, copper oxide and tin sulfide.

[0029] The second aspect of the present invention provides a method for preparing the biomass-derived carbon material according to the first aspect, wherein the method includes: mixing the biomass precursor and the metal salt and then performing one-step pyrolysis to obtain the biomass-derived carbon material.

[0030] In the present invention, the biomass-derived carbon material is prepared by simply mixing the biomass precursor containing specific functional groups with the metal salt and performing one-step pyrolysis, and can be used as a fast-charging anode material for alkali metal ion batteries. During the preparation process, the specific functional groups in the biomass precursor coordinate with the metal salt ions to achieve uniform distribution of metal ions on the surface of the biomass. During the pyrolysis process, the metal salt is in-situ reduced by the biomass carbon into elemental metal or metal compound, and is uniformly loaded on the surface of the anode material in the form of nano-clusters or nano-particles.

[0031] In some embodiments of the present invention, the cation of the metal salt is selected from Sn 2+ , Cu 2+ , Fe 2+ , Fe 3+ , Zn 2+ , Co 2+ , Mn 2+ , Ni 2+ , Cr 3+ , Cd 2+ , Ag + and Pb 2+ , preferably at least one of Sn 2+ , Zn 2+ and Cu 2+ .

[0032] In some embodiments of the present invention, the anion of the metal salt is selected from Cl - , Br - , I - , NO 3 - , SO 4 2- , ClO 4- , ClO 3 - , CH 3 COO - and C 6 H 5 O 7 3- at least one of, preferably Cl - and / or NO 3 - .

[0033] In some embodiments of the present invention, the mass ratio of the biomass precursor to the metal salt is 1 - 100:1, preferably 1 - 50:1, and more preferably 10:1.

[0034] In some embodiments of the present invention, the mixing process includes: mixing the biomass precursor, the metal salt and water, stirring for 24 h, then pre-freezing for 10 h and freeze-drying for 24 h to obtain the salt-impregnated biomass precursor. In the present invention, the sample is first frozen into a solid at a low temperature, and then under vacuum and low temperature conditions, the pre-frozen sample is thoroughly dried by sublimation and desorption, that is, freeze-dried.

[0035] In some embodiments of the present invention, the one-step pyrolysis process includes: drying the salt-impregnated biomass precursor, heating up and holding the temperature, and cooling in a protective atmosphere to obtain the biomass-derived carbon material.

[0036] In some embodiments of the present invention, the protective atmosphere is an argon or nitrogen atmosphere;

[0037] In some embodiments of the present invention, the heating rate is 1 - 20 °C / min, preferably 1 - 10 °C / min, and more preferably 5 °C / min;

[0038] In some embodiments of the present invention, the holding temperature is 300 - 3000 °C, preferably 500 - 2000 °C, and more preferably 1000 °C;

[0039] In some embodiments of the present invention, the holding time is 0.5 - 5 h, preferably 1 - 3 h, and more preferably 2 h.

[0040] The third aspect of the present invention provides the biomass-derived carbon material obtained by the preparation method described in the second aspect.

[0041] The fourth aspect of the present invention provides the application of the biomass-derived carbon material described in the first aspect or the third aspect as a negative electrode material for an alkali metal ion battery.

[0042] The fifth aspect of the present invention provides an alkali metal ion battery, wherein the alkali metal ion battery uses the biomass-derived carbon material described in the first aspect or the third aspect as the negative electrode material.

[0043] In some embodiments of the present invention, the alkali metal ion battery is selected from at least one of a sodium ion battery, a lithium ion battery, and a potassium ion battery.

[0044] In the present invention, the biomass-derived carbon material described in the first aspect or the third aspect is mixed uniformly with acetylene black and PVDF (polyvinylidene fluoride) in a mass ratio of (5-10):1:1 (preferably 8:1:1), using NMP (N-methylpyrrolidone) as a solvent, ground uniformly in a mortar, and then uniformly coated on a copper foil and dried in a vacuum oven at 120 °C for 24 h to prepare negative electrode sheets under different treatment conditions.

[0045] In the present invention, the assembly of the alkali metal ion half-cell includes the following steps: assembling the negative electrode sheet with an alkali metal (preferably one of sodium, lithium, and potassium) as the counter electrode to form an alkali metal ion half-cell, with an electrolyte addition amount of 200 μL; the assembly of the alkali metal ion full-cell includes the following steps: assembling the negative electrode sheet with a positive electrode material (preferably one of NVP (sodium vanadium phosphate), LFP (lithium iron phosphate), and KVPF (potassium vanadium fluorophosphate)) to form an alkali metal ion full-cell, with an electrolyte addition amount of 200 μL.

[0046] The electrolyte is 1M NaPF 6 in diglyme, 1M LiPF 6 -EC / DMC / DEC-5% FEC, 1M KPF 6 in diglyme.

[0047] The voltage window of the full-cell is set to one of 2.5-3.8V, 2.5-4.2V, and 2.5-4.8V.

[0048] The half-cell is subjected to charge-discharge performance testing at a rate of 4-20C within a voltage range of 0.01-3V. The first-cycle reversible capacity is 300-2000 mAh / g (preferably 500-1000 mAh / g), and the capacity retention rate is 40-100% (preferably 50-90%) after 500-1000 cycles.

[0049] The full cell was subjected to long cycle testing at a rate of 4-20C under the condition that the N / P ratio was 1-2 (preferably 1-1.5). The reversible capacity of the first cycle was 30-100% (preferably 40-90%) of the theoretical capacity of the cathode material. After 500-2000 (preferably 500-1000) cycles, the capacity retention rate was 50-100% (preferably 50-90%).

[0050] After testing, no alkali metals were precipitated on the surface of the negative electrode during the fast charging process.

[0051] The present invention will be described in detail below through examples.

[0052] For those not specifying specific conditions in the following examples and comparative examples, they were carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they were all conventional products that could be obtained through commercial channels.

[0053] Example 1

[0054] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0055] Sulfonated cellulose (containing sulfonic acid groups) and tin chloride were mixed in water at a mass ratio of 10:1 and stirred for 24 h. Subsequently, the mixed sample was transferred to a freeze dryer, pre-frozen for 10 h, and then freeze-dried for 24 h to obtain a salt-impregnated cellulose precursor. The dried sample was heated to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and held for 2 h. When the sample temperature cooled to room temperature, the sample in the porcelain boat was taken out to obtain a cellulose-derived carbon material with elemental tin loaded on the surface.

[0056] The transmission electron microscope image of the cellulose-derived carbon material is as Figure 1 shown. The elemental tin was uniformly distributed on the cellulose carbon in the form of nanoclusters with a diameter of 1-2 nm. The cellulose-derived carbon material was characterized by XRD and Raman, as Figure 2 and Figure 3 shown. By comparing the PDF card, the characteristic peaks of elemental Sn can be seen, indicating that SnCl 2 underwent an in-situ redox reaction with cellulose carbon during the carbonization process to be converted into elemental Sn. TG testing was carried out on the cellulose-derived carbon. Compared with pure cellulose carbon, the loading amount of elemental tin was about 5.84 wt%.

[0057] Example 2

[0058] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0059] Mix sulfonated starch (containing sulfonic acid groups) and stannous chloride in water at a mass ratio of 10:1, stir for 24 h, and then transfer the mixed sample to a freeze dryer for pre-freezing for 10 h and then freeze-drying for 24 h to obtain the salt-impregnated starch precursor. Heat the dried sample to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain the starch-derived carbon material with elemental tin loaded on the surface.

[0060] Example 3

[0061] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0062] Mix sulfonated tannic acid (containing sulfonic acid groups) and stannous chloride in water at a mass ratio of 10:1, stir for 24 h, and then transfer the mixed sample to a freeze dryer for pre-freezing for 10 h and then freeze-drying for 24 h to obtain the salt-impregnated tannic acid precursor. Heat the dried sample to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain the tannic acid-derived carbon material with elemental tin loaded on the surface.

[0063] Example 4

[0064] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0065] Mix phosphated cellulose (containing phosphoric acid groups) and stannous chloride in water at a mass ratio of 10:1, stir for 24 h, and then transfer the mixed sample to a freeze dryer for pre-freezing for 10 h and then freeze-drying for 24 h to obtain the salt-impregnated cellulose precursor. Heat the dried sample to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain the cellulose-derived carbon material with elemental tin loaded on the surface.

[0066] Example 5

[0067] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0068] Mix sulfonated cellulose (containing sulfonic acid groups) and zinc chloride in water at a mass ratio of 10:1, stir for 24 h, and then transfer the mixed sample to a freeze dryer for pre-freezing for 10 h and then freeze-drying for 24 h to obtain the salt-impregnated cellulose precursor. Heat the dried sample to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain the cellulose-derived carbon material with elemental zinc loaded on the surface.

[0069] Example 6

[0070] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0071] Mix sulfonated cellulose (containing sulfonic acid groups) and copper nitrate in water at a mass ratio of 10:1, stir for 24 h, then transfer the mixed sample to a freeze dryer, pre-freeze for 10 h and then freeze-dry for 24 h to obtain the salt-impregnated cellulose precursor. Heat the dried sample in an argon atmosphere at a heating rate of 5 °C / min to 1000 °C and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain a cellulose-derived carbon material with copper oxide loaded on the surface.

[0072] Example 7

[0073] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0074] Mix sulfonated cellulose (containing sulfonic acid groups) and stannous chloride in water at a mass ratio of 1:1, stir for 24 h, then transfer the mixed sample to a freeze dryer, pre-freeze for 10 h and then freeze-dry for 24 h to obtain the salt-impregnated cellulose precursor. Heat the dried sample in an argon atmosphere at a heating rate of 5 °C / min to 1000 °C and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain a cellulose-derived carbon material with elemental tin loaded on the surface.

[0075] Example 8

[0076] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0077] Mix sulfonated cellulose (containing sulfonic acid groups) and stannous chloride in water at a mass ratio of 10:1, stir for 24 h, then transfer the mixed sample to a freeze dryer, pre-freeze for 10 h and then freeze-dry for 24 h to obtain the salt-impregnated cellulose precursor. Heat the dried sample in an argon atmosphere at a heating rate of 10 °C / min to 1000 °C and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain a cellulose-derived carbon material with elemental tin loaded on the surface.

[0078] Example 9

[0079] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0080] Mix sulfonated cellulose (containing sulfonic acid groups) and stannous chloride in water at a mass ratio of 10:1, stir for 24 h, then transfer the mixed sample to a freeze dryer, pre-freeze for 10 h and then freeze-dry for 24 h to obtain the salt-impregnated cellulose precursor. Heat the dried sample in an argon atmosphere at a heating rate of 5 °C / min to 500 °C and hold for 2 h. When the sample temperature cools to room temperature, take out the sample in the porcelain boat to obtain a cellulose-derived carbon material with tin sulfide loaded on the surface.

[0081] Example 10

[0082] This example is used to illustrate the preparation of biomass-derived carbon materials.

[0083] Sulfonated cellulose (containing sulfonic acid groups) and tin chloride were mixed in water at a mass ratio of 10:1, and stirred for 24 h. Subsequently, the mixed sample was transferred to a freeze dryer, pre-frozen for 10 h, and then freeze-dried for 24 h to obtain a salt-impregnated cellulose precursor. The dried sample was heated to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and held for 3 h. When the sample temperature cooled to room temperature, the sample in the porcelain boat was taken out to obtain a cellulose-derived carbon material with elemental tin loaded on the surface.

[0084] Comparative Example 1

[0085] Pure cellulose (without functional groups) and tin chloride were mixed in water at a mass ratio of 10:1, and stirred for 24 h. Subsequently, the mixed sample was transferred to a freeze dryer, pre-frozen for 10 h, and then freeze-dried for 24 h to obtain a salt-impregnated cellulose precursor. The dried sample was heated to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and held for 2 h. When the sample temperature cooled to room temperature, the sample in the porcelain boat was taken out to obtain a cellulose-derived carbon material with elemental tin loaded on the surface.

[0086] Comparative Example 2

[0087] Kuraray Type-2 coconut shell hard carbon material from Japan.

[0088] Comparative Example 3

[0089] Sulfonated cellulose (containing sulfonic acid groups) was heated to 1000 °C at a heating rate of 5 °C / min in an argon atmosphere and held for 2 h. When the sample temperature cooled to room temperature, the sample in the porcelain boat was taken out to obtain a pure cellulose carbon material.

[0090] Test Example 1

[0091] The biomass-derived carbon materials prepared in Examples 1-10 and the carbon materials of Comparative Examples 1-3 were subjected to TEM and TG tests to obtain the loading characteristics of elemental metals or metal compounds. The experimental results are shown in Table 1.

[0092] Table 1

[0093]

[0094]

[0095] Test Example 2

[0096] The biomass-derived carbon materials prepared in Examples 1-10 and the carbon materials in Comparative Examples 1-3 were uniformly mixed with acetylene black and PVDF in a mass ratio of 8:1:1, and NMP was used as a solvent. After being uniformly ground in a mortar, the mixture was uniformly scraped onto a copper foil and dried in a vacuum oven at 120°C for 24 hours to prepare negative electrode sheets under different treatment conditions.

[0097] The negative electrode sheets obtained in Examples 1-10 and Comparative Examples 1-3 were treated with 1M NaPF 6 In diglyme is the electrolyte for assembling sodium ion batteries, and the amount of electrolyte added is 200μL. The negative electrode sheet is assembled with sodium metal as the counter electrode to obtain a sodium ion half-cell for charge and discharge performance testing. The test results are as follows Figure 4 The negative electrode sheet was used as the negative electrode of the full battery, NVP was used as the positive electrode, and the sodium ion full battery was assembled under the condition of N / P ratio of 1.1 for long cycle performance test. The test results are shown in Figure 5 shown.

[0098] The cycle life in this test example and the following test examples refers to the absence of abnormal phenomena such as short circuit or voltage fluctuation within the number of cycles; the capacity retention rate refers to the capacity retention rate under the corresponding cycle life.

[0099] (1) The prepared sodium ion half-cell was tested for charge and discharge performance at a rate of 4C in the voltage range of 0.01-3V. The test results are shown in Table 2.

[0100] Table 2

[0101]

[0102] It can be seen from the above test results that the half-cell assembled with the biomass-derived carbon material prepared in Examples 1-10 can reach a first-cycle reversible capacity of more than 562.14 mAh / g at a rate of 4C, a cycle life of more than 522 cycles, and a capacity retention rate of more than 53.84%. By adjusting the material ratio and reaction conditions, the first-cycle reversible capacity of the half-cell can reach 860.14 mAh / g at a rate of 4C, the cycle life can reach more than 800 cycles, and the capacity retention rate can reach 77.36%, which is significantly better than the carbon material of Comparative Examples 1-3. When the diameter of the loaded metal element or metal compound increases, the reversible capacity and cycle life of the half-cell are significantly reduced.

[0103] (2) The prepared sodium ion full battery was subjected to a long cycle performance test at a rate of 4C, with the voltage window set to 2.5-3.8V. The test results are shown in Table 3.

[0104] Table 3

[0105]

[0106]

[0107] It can be seen from the above test results that the full battery assembled with the biomass-derived carbon material prepared in Examples 1-10 can reach a first-cycle reversible capacity of more than 93.47 mAh / g at a rate of 4C, a cycle life of more than 537 cycles, a capacity retention rate of more than 58.34%, and an average coulombic efficiency of more than 96.54%. By adjusting the material ratio and reaction conditions, the first-cycle reversible capacity of the full battery at a rate of 4C can reach 102.56 mAh / g, a cycle life of more than 700 cycles, a capacity retention rate of 85.54%, and an average coulombic efficiency of 99.45%, which is significantly better than the carbon material of Comparative Examples 1-3. When the diameter of the loaded metal element or metal compound increases, the reversible capacity, cycle life, capacity retention rate and average coulombic efficiency of the full battery are significantly reduced.

[0108] (3) The sodium ion full batteries prepared in Examples 1-10 and Comparative Examples 1-3 were cycled for 20 cycles at a rate of 4C, and then the negative electrode sheets were disassembled and taken out for SEM testing to observe whether sodium was precipitated on the negative electrode surface. The test results are shown in Table 4.

[0109] Table 4

[0110]

[0111]

[0112] It can be seen from the above test results that after the full batteries assembled with the biomass-derived carbon materials of Examples 1-10 were cycled 20 times at a rate of 4C, there was no sodium precipitation on the negative electrode surface, while the carbon materials of Comparative Examples 1-3 all produced sodium precipitation during the cycle process, indicating that metal elements or metal compounds in the form of nanoclusters or nanoparticles can significantly inhibit the sodium precipitation on the negative electrode surface under fast charging conditions.

[0113] Test Example 3

[0114] The biomass-derived carbon materials prepared in Examples 1-10 and the carbon materials in Comparative Examples 1-3 were uniformly mixed with acetylene black and PVDF in a mass ratio of 8:1:1, and NMP was used as a solvent. After being uniformly ground in a mortar, the mixture was uniformly scraped onto a copper foil and dried in a vacuum oven at 120°C for 24 hours to prepare negative electrode sheets under different treatment conditions.

[0115] The negative electrode sheets obtained in Examples 1-10 and Comparative Examples 1-3 were heated to 1M LiPF 6-EC / DMC / DEC-5%FEC was used as the electrolyte to assemble a lithium-ion battery, and the amount of electrolyte added was 200μL. The negative electrode sheet was used as the negative electrode of the full battery, and LFP was used as the positive electrode. The lithium-ion full battery was assembled under the condition of an N / P ratio of 1.1 for long-cycle performance testing.

[0116] (1) The prepared lithium ion half-cell was subjected to a charge and discharge performance test at a rate of 4C within a voltage range of 0.01-3V. The test results are shown in Table 5.

[0117] Table 5

[0118]

[0119]

[0120] It can be seen from the above test results that the half-cell assembled with the biomass-derived carbon material prepared in Examples 1-10 can reach a first-cycle reversible capacity of more than 593.24 mAh / g at a rate of 4C, a cycle life of more than 568 cycles, and a capacity retention rate of more than 51.24%. By adjusting the material ratio and reaction conditions, the first-cycle reversible capacity of the half-cell can reach 884.25 mAh / g at a rate of 4C, the cycle life can reach more than 834 cycles, and the capacity retention rate can reach 81.24%, which is significantly better than the carbon material of Comparative Examples 1-3. When the diameter of the loaded metal element or metal compound increases, the reversible capacity and cycle life of the half-cell are significantly reduced.

[0121] (2) The prepared lithium-ion full battery was subjected to a long cycle performance test at a rate of 4C, with the voltage window set to 2.5-4.2V. The test results are shown in Table 6.

[0122] Table 6

[0123]

[0124]

[0125] It can be seen from the above test results that the full battery assembled with the biomass-derived carbon material prepared in Examples 1-10 can reach a first-cycle reversible capacity of more than 102.75 mAh / g at a rate of 4C, a cycle life of more than 627 cycles, a capacity retention rate of more than 60.28%, and an average coulombic efficiency of more than 94.64%. By adjusting the material ratio and reaction conditions, the first-cycle reversible capacity of the full battery at a rate of 4C can reach 133.24 mAh / g, a cycle life of more than 788 cycles, a capacity retention rate of 88.91%, and an average coulombic efficiency of 99.74%, which is significantly better than the carbon material of Comparative Examples 1-3. When the diameter of the loaded metal element or metal compound increases, the reversible capacity, cycle life, capacity retention rate and average coulombic efficiency of the full battery are significantly reduced.

[0126] (3) The lithium-ion full batteries prepared in Examples 1-10 and Comparative Examples 1-3 were cycled for 20 cycles at a rate of 4C, and then the negative electrode sheets were disassembled and tested by SEM to observe whether lithium was deposited on the negative electrode surface. The test results are shown in Table 7.

[0127] Table 7

[0128] Number Whether lithium is deposited on the negative electrode surface Example 1 No Example 2 No Example 3 No Example 4 No Example 5 No Example 6 No Example 7 No Example 8 No Example 9 No Example 10 No Comparative Example 1 Yes Comparative Example 2 Yes Comparative Example 3 Yes

[0129] It can be seen from the above test results that the full batteries assembled with biomass-derived carbon materials of Examples 1-10 showed no lithium deposition on the surface after 20 cycles at a rate of 4C, while the carbon materials of Comparative Examples 1-3 all produced lithium deposition during the cycle process, indicating that metal elements or metal compounds in the form of nanoclusters or nanoparticles can significantly inhibit lithium deposition on the negative electrode surface under fast charging conditions.

[0130] Test Example 4

[0131] The biomass-derived carbon materials prepared in Examples 1-10 and the carbon materials in Comparative Examples 1-3 were uniformly mixed with acetylene black and PVDF in a mass ratio of 8:1:1, and NMP was used as a solvent. After being uniformly ground in a mortar, the mixture was uniformly scraped onto a copper foil and dried in a vacuum oven at 120°C for 24 hours to prepare negative electrode sheets under different treatment conditions.

[0132] The negative electrode sheets obtained in Examples 1-10 and Comparative Examples 1-3 were heated to 1M KPF 6 In diglyme was used as the electrolyte to assemble a potassium ion battery, and the amount of electrolyte added was 200 μL. The negative electrode sheet was used as the negative electrode of the full battery, and KVPF was used as the positive electrode. The potassium ion full battery was assembled under the condition of an N / P ratio of 1.2 for long cycle performance testing.

[0133] (1) The prepared potassium ion half-cell was subjected to a charge and discharge performance test at a rate of 4C in the voltage range of 0.01-3V. The test results are shown in Table 8.

[0134] Table 8

[0135]

[0136]

[0137] It can be seen from the above test results that the half-cell assembled with the biomass-derived carbon material prepared in Examples 1-10 can reach a reversible capacity of more than 508.73 mAh / g at a rate of 4C, a cycle life of more than 506 cycles, and a capacity retention rate of more than 53.72%. By adjusting the material ratio and reaction conditions, the first reversible capacity of the half-cell can reach 749.95 mAh / g at a rate of 4C, the cycle life can reach more than 724 cycles, and the capacity retention rate can reach 69.54%, which is significantly better than the carbon material of Comparative Examples 1-3. When the diameter of the loaded metal element or metal compound increases, the reversible capacity and cycle life of the half-cell are significantly reduced.

[0138] (2) The prepared potassium ion full battery was subjected to a long cycle performance test at a rate of 4C, with the voltage window set to 2.5-4.8V. The test results are shown in Table 9.

[0139] Table 9

[0140]

[0141]

[0142] It can be seen from the above test results that the full battery assembled with the biomass-derived carbon material prepared in Examples 1-10 can reach a first-cycle reversible capacity of more than 69.54 mAh / g at a rate of 4C, a cycle life of more than 509 cycles, a capacity retention rate of more than 52.06%, and an average coulombic efficiency of more than 92.72%. By adjusting the material ratio and reaction conditions, the first-cycle reversible capacity of the full battery at a rate of 4C can reach 85.75 mAh / g, a cycle life of more than 643 cycles, a capacity retention rate of 74.32%, and an average coulombic efficiency of 99.46%, which is significantly better than the carbon material of Comparative Examples 1-3. When the diameter of the loaded metal element or metal compound increases, the reversible capacity, cycle life, capacity retention rate and average coulombic efficiency of the full battery are significantly reduced.

[0143] (3) The potassium ion full batteries prepared in Examples 1-10 and Comparative Examples 1-3 were cycled for 20 cycles at a rate of 4C, and then the negative electrode sheets were disassembled and taken out for SEM testing to observe whether potassium was deposited on the negative electrode surface. The test results are shown in Table 10.

[0144] Table 10

[0145]

[0146]

[0147] From the above test results, it can be seen that after 20 cycles at a rate of 4C, there is no potassium precipitation on the surface of the all-battery assembled with the biomass-derived carbon materials of Examples 1-10, while potassium precipitation occurs during the cycling of the carbon materials of Comparative Examples 1-3, indicating that metallic elements or metal compounds in the form of nanoclusters or nanoparticles can significantly inhibit potassium precipitation on the surface of the negative electrode under fast charging conditions.

[0148] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A biomass-derived carbon material, characterized in that: The surface of the biomass-derived carbon material is loaded with nanoclusters or nanoparticles of metal elements or metal compounds.

2. The biomass-derived carbon material according to claim 1, wherein The loading amount of the metal element or metal compound is 1-50wt%, preferably 5-40wt%, and more preferably 5.24-27.64wt%; Preferably, the diameter of the nanocluster is 1-10 nm, preferably 1-4 nm; Preferably, the diameter of the nanoparticles is 1-100 nm, preferably 10-100 nm, and more preferably 2-30 nm.

3. The biomass-derived carbon material according to claim 1 or 2, wherein: The biomass precursor used in the biomass-derived carbon material is selected from at least one of cellulose, chitosan, starch, collagen, tannic acid, lignin and oxalic acid, preferably at least one of sulfonated cellulose, sulfonated starch, sulfonated tannic acid and phosphated cellulose; Preferably, the biomass precursor used in the biomass-derived carbon material contains a functional group, and the functional group is selected from at least one of a sulfonic acid group, a phosphoric acid group, an amino group, a carboxyl group, a hydroxyl group, a thiol group, a nitro group and a pyridyl group, preferably a sulfonic acid group and / or a phosphoric acid group; Preferably, the metal element or metal compound is selected from at least one of elemental tin, tin oxide, tin sulfide, elemental copper, copper oxide, copper sulfide, copper phosphide, elemental iron, iron oxide, iron sulfide, iron phosphide, elemental zinc, zinc oxide, zinc sulfide, zinc phosphide, elemental cobalt, cobalt oxide, cobalt sulfide, cobalt phosphide, elemental manganese, manganese oxide, manganese sulfide, manganese phosphide, elemental nickel, nickel oxide, nickel sulfide, nickel phosphide, elemental chromium, chromium oxide, chromium sulfide, chromium phosphide, cadmium oxide, cadmium sulfide, elemental silver, elemental lead, lead oxide, lead sulfide and lead phosphide, and is preferably at least one of elemental tin, elemental zinc, copper oxide and tin sulfide.

4. A method for preparing a biomass-derived carbon material according to any one of claims 1 to 3, characterized in that: The method comprises: mixing a biomass precursor and a metal salt and then performing a one-step pyrolysis to obtain the biomass-derived carbon material.

5. The preparation method according to claim 4, wherein The cation of the metal salt is selected from Sn 2+ , Cu 2+ , Fe 2+ , Fe 3 + 、Zn 2+ 、Co 2+ , Mn 2+ 、Ni 2+ Cr 3+ 、Cd 2+ 、Ag + and Pb 2+ At least one of, preferably Sn 2+ 、Zn 2+ and Cu 2+ At least one of; Preferably, the anion of the metal salt is selected from Cl - Br - ,I - 、NO3 - 、SO4 2- 、ClO4 - 、ClO3 - 、CH3COO - and C6H5O7 3- At least one of, preferably Cl - and / or NO3 - .

6. The preparation method according to claim 4 or 5, wherein: The mass ratio of the biomass precursor to the metal salt is 1-100:1, preferably 1-50:1, and more preferably 10:1; Preferably, the mixing process comprises: mixing the biomass precursor, the metal salt and water and stirring for 24 hours, and then pre-freezing for 10 hours and freeze-drying for 24 hours to obtain the salt-soaked biomass precursor.

7. The preparation method according to claim 6, wherein: The one-step pyrolysis process comprises: drying the salt-soaked biomass precursor, heating and keeping the temperature in a protective atmosphere, and cooling to obtain the biomass-derived carbon material; Preferably, the protective atmosphere is an argon or nitrogen atmosphere; Preferably, the heating rate is 1-20°C / min, preferably 1-10°C / min, and more preferably 5°C / min; Preferably, the insulation temperature is 300-3000°C, preferably 500-2000°C, and more preferably 1000°C; Preferably, the insulation time is 0.5-5h, preferably 1-3h, and more preferably 2h.

8. The biomass-derived carbon material obtained according to the preparation method of claims 4-7.

9. Use of the biomass-derived carbon material according to claims 1-3 or claim 8 as a negative electrode material for alkali metal ion batteries.

10. An alkali metal ion battery, characterized in that: The alkali metal ion battery uses the biomass-derived carbon material of claims 1 to 3 or claim 8 as the negative electrode material; Preferably, the alkali metal ion battery is selected from at least one of a sodium ion battery, a lithium ion battery and a potassium ion battery.

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