Preparation method of biomass charcoal anchored sea urchin-like Ni, Co-MOF, biomass charcoal and application thereof in supercapacitor
By combining porous carbon from waste corn cobs with sea urchin-like Ni,Co-MOF using a solvothermal method, the problems of capacitance, conductivity, and stability of supercapacitor electrode materials were solved, achieving the preparation of high-performance, low-cost electrode materials and improving the energy and power density of supercapacitors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHEAST FORESTRY UNIV
- Filing Date
- 2022-08-30
- Publication Date
- 2026-07-07
AI Technical Summary
Existing MOF/carbon-based composite materials used as electrode materials for supercapacitors suffer from insufficient capacitance, conductivity, and cycle stability, as well as high preparation costs, complex processes, easy metal agglomeration, and poor electrochemical performance.
A simple solvothermal method was used to combine porous char derived from waste corn cobs with sea urchin-like Ni,Co-MOF. By anchoring the sea urchin-like Ni,Co-MOF with biochar, the specific surface area and active sites of the material were increased, agglomeration was prevented, and the conductivity and electrochemical performance were improved.
This improved the specific capacitance, energy density, and power density of supercapacitors, enhanced cycle stability, and reduced manufacturing costs.
Smart Images
Figure CN115547704B_ABST
Abstract
Description
Technical Field
[0001] This invention pertains to the assembly technology of novel renewable and clean energy storage devices, and relates to a method for preparing biochar-anchored sea urchin-shaped Ni,Co-MOF, the biochar-anchored sea urchin-shaped Ni,Co-MOF prepared by this method, and the application of biochar-anchored sea urchin-shaped Ni,Co-MOF in supercapacitors. Background Technology
[0002] With the increasing severity of environmental pollution and fossil resource shortages, the development and design of renewable, green, and sustainable clean technologies and materials have become imperative. Supercapacitors, as novel energy storage devices, have attracted significant interest in fields such as electronics, electric vehicles, smart networks, defense, and aerospace due to their high power density, high energy density, long cycle life, and fast charge / discharge speed. Electrodes, as key components of supercapacitors, directly affect capacitor performance. Therefore, selecting, developing, and designing high-performance, highly stable electrode materials for supercapacitors is one of the important directions for energy storage development.
[0003] Metal-organic frameworks (MOFs) are porous crystalline framework materials formed by coordination bonding of metals / metal clusters with organic ligands. Due to the tunability of the organic ligands and metal nodes, MOFs possess advantages such as large specific surface area, tunable porosity, and structural diversity. Controllable structures and tunable porosity can yield more active sites conducive to energy conversion, making them promising electrode materials. Even so, the relatively small capacitance, poor conductivity, and cycling stability of MOFs still limit their application in electrochemical energy storage. Therefore, combining conductive and stable materials with MOFs to construct composite materials is a highly effective solution.
[0004] Existing technologies such as NiCo-MOF / MWCNT (Solvothermal synthesis of flower-string-like NiCo-MOF / MWCNT composites as a high-performance supercapacitor electrode material, Journal of Solid State Chemistry 277(2019)575–586, doi: 10.1016 / j.jssc.2019.07.019) and NiCo-MOF@GO (2D / 2D NiCo-MOFsg-1O hybrid nanosheets for high-performance asymmetrical supercapacitor, Diamond & Related Materials 115(2021)108358, doi: 10.1016 / j.diamond.2021.108358) have improved the capacitance, conductivity, and cycle stability of MOF materials when used as electrode materials for supercapacitors, but they still cannot achieve the ideal results. To realize the practical application of supercapacitors, further improvements are needed in the specific capacitance, energy density / power density, and cycle stability of these electrode materials. Furthermore, the MOF / carbon-based electrode materials prepared above suffer from high manufacturing costs, complex processes, easy metal agglomeration, and poor electrochemical performance. Therefore, constructing simple, inexpensive, green, sustainable, and high-performance MOF composite materials remains a key research focus and challenge.
[0005] To address the shortcomings of existing technologies, this invention utilizes a simple one-step solvothermal method to prepare high-performance supercapacitor electrode materials using green, renewable, and low-cost waste corn cob-derived porous carbon (CPC) and urchin-like Ni,Co-MOF. The stable support and protection of the urchin-like Ni,Co-MOF by CPC not only increases the specific surface area and exposed active sites of the material but also prevents agglomeration, enhances the contact between the material and the electrolyte, and accelerates electron / ion transport efficiency, thereby improving the material's specific capacitance, energy / power density, and cycle stability. Summary of the Invention
[0006] The purpose of this invention
[0007] (1) A simple solvothermal method is provided to prepare a biochar-anchored sea urchin-like Ni,Co-MOF composite material and its application in supercapacitors;
[0008] (2) A simple method was used to prepare sea urchin-like Ni,Co-MOF to solve the problem of agglomeration of traditional metal oxide and metal hydroxide materials;
[0009] (3) Use corn cob porous carbon material to anchor sea urchin-shaped Ni,Co-MOF to protect and support the sea urchin-shaped Ni,Co-MOF, thereby improving the problems of low conductivity and unstable electrochemical performance of Ni,Co-MOF;
[0010] (4) By anchoring sea urchin-shaped Ni,Co-MOF with biochar, an electrode material with a large specific surface area and abundant active sites is obtained, which increases the contact between the electrode and the electrolyte active material, shortens the transport path of electrolyte ions, improves the transport efficiency of electrons and ions, and thus improves the energy density of the supercapacitor.
[0011] A method for preparing biochar-anchored sea urchin-like Ni,Co-MOF, the method comprising the following steps:
[0012] (1) The waste corn cobs are washed, dried and crushed to obtain corn cob powder. A certain mass ratio of corn cob powder is soaked in potassium permanganate solution for a certain time. Then, it is dried in an oven for 12-24 hours to obtain the dried sample.
[0013] (2) Place the dried sample from (1) into a ceramic boat and heat it to a certain temperature at a heating rate of 5℃ / min under a nitrogen atmosphere. Hold it for 60-360 min. Then, wash the obtained product with H2SO4 and water until pH=7. Finally, dry it in an oven at 120℃ to obtain corn cob porous carbon (CPC) with a hierarchical porous structure.
[0014] (3) A certain proportion of nickel and cobalt metal salts, organic ligands (Ni,Co-MOF precursors) and CPC are mixed in a DMF solution at a certain mass ratio, and then ultrasonicated for 5 to 50 minutes at 40 to 100% ultrasonic power on an ultrasonic cleaner to obtain a uniform mixed solution.
[0015] (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at a certain temperature for a period of time.
[0016] (5) The product after the solvothermal reaction was naturally cooled to room temperature, centrifuged at 2500-6000 rpm, washed with ethanol 3-5 times, and dried at 35-120℃ to prepare corn cob porous carbon anchored sea urchin-like Ni,Co-MOF (Ni,Co-MOF@CPC).
[0017] Preferably, in step (1), the corn cob powder of a certain mass ratio is soaked in potassium permanganate solution for a certain time, wherein the mass ratio of corn cob powder to potassium permanganate is 1:0 to 1:7, and the soaking time is 12 to 48 hours.
[0018] Preferably, in step (3), a certain proportion of nickel and cobalt metal salts are mixed with organic ligands (Ni,Co-MOF precursor) and CPC in a DMF solution at a certain mass ratio, wherein the mass ratio of nickel and cobalt metal salts in the Ni,Co-MOF precursor is 1:1 to 9:1, and the mass ratio of CPC to Ni,Co-MOF precursor is 1% to 50%.
[0019] Preferably, the solvothermal temperature of step (4) is 80–240°C and the solvothermal reaction time is 3–48 h.
[0020] The present invention also provides biochar-anchored sea urchin-shaped Ni,Co-MOF prepared by the above-mentioned method for preparing biochar-anchored sea urchin-shaped Ni,Co-MOF.
[0021] Preferably, the biochar-anchored sea urchin-like Ni,Co-MOF@CPC is used as an electrode material for the positive electrode of a supercapacitor.
[0022] This invention selects the optimal temperature, time, and optimal ratio for the prepared Ni,Co-MOF@CPC composite material through electrochemical performance testing. Electrochemical testing of the electrode materials mainly uses CV, GCD, and EIS. The Ni,Co-MOF@CPC composite material prepared under optimal conditions and CPC are used as positive and negative electrodes, respectively, and assembled with KOH-PVA gel electrolyte to form an asymmetric supercapacitor (Ni,Co-MOF@CPC / / CPC). Electrochemical test results show that Ni,Co-MOF@CPC / / CPC exhibits large specific capacitance, high energy density and power density, and excellent cycle stability. Attached Figure Description
[0023] Figure 1 Scanning electron microscope (SEM) and transmission electron microscope (TEM) images of Ni,Co-MOF@CPC composite materials;
[0024] Figure 2 Electrochemical performance and GCD cycling test results for Ni,Co-MOF@CPC electrodes and Ni,Co-MOF@CPC / / CPC electrodes. Detailed Implementation
[0025] These embodiments are merely illustrative of the invention, but the invention is not limited to these embodiments.
[0026] Example 1:
[0027] (1) After washing, drying and crushing the waste corn cobs, a certain mass ratio of corn cob powder of 1:1 was soaked in potassium permanganate solution for 12 hours. Then, it was dried in an oven for 24 hours.
[0028] (2) The dried sample from (1) was placed in a ceramic boat and heated to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and held for 60 min. Then, the product was washed with H2SO4 and water until pH=7. Finally, it was dried in an oven at 120°C to obtain hierarchical porous corn cob carbon (CPC).
[0029] (3) Nickel and cobalt metal salts were mixed in a 1:1 ratio with organic ligands (Ni,Co-MOF precursor) and CPC at a mass ratio of 1% in DMF solution. The mixture was then ultrasonicated at 100% ultrasonic power for 10 min in an ultrasonic cleaner to obtain a homogeneous mixed solution.
[0030] (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at 100°C for 8 hours.
[0031] (5) The product after the solvothermal reaction was naturally cooled to room temperature, centrifuged at 4000 rpm, washed 4 times with ethanol, and dried under vacuum at 40°C to prepare Ni,Co-MOF@CPC-1.
[0032] The physicochemical performance test results show that the specific surface area of the prepared Ni,Co-MOF@CPC-1% material is 50.19 m². 2 g -1 Electrochemical performance test results show that: at 1Ag -1 At a current density of 1%, the specific capacitance of Ni,Co-MOF@CPC-1% is 1286.37 F g. -1 After 5000 GCD cycles, the capacitance retention of the Ni,Co-MOF@CPC-1% electrode was 78.2%.
[0033] Example 2:
[0034] (1) Nickel and cobalt metal salts were mixed with organic ligands (Ni,Co-MOF precursor) in DMF solution at a ratio of 3:1. The mixture was then ultrasonicated at 70% ultrasonic power for 10 min in an ultrasonic cleaner to obtain a homogeneous mixed solution.
[0035] (2) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at 160°C for 24 hours.
[0036] (3) The product after the solvothermal reaction was naturally cooled to room temperature, centrifuged at 5000 rpm, washed three times with ethanol, and then vacuum dried at 80℃ to prepare Ni,Co-MOF. Physicochemical performance tests showed that the specific surface area of the prepared Ni,Co-MOF material was 44.28 m². 2 g -1 Electrochemical performance test results show that: at 1Ag -1 At a current density of 1215.3 F g, the specific capacitance of Ni,Co-MOF is 1215.3 F g. -1 After 5000 GCD cycles, the capacitance retention of the Ni,Co-MOF@CPC-1% electrode was 73.5%.
[0037] Example 3:
[0038] (1) After washing, drying and crushing the waste corn cobs, a certain mass ratio of corn cob powder of 4:1 was soaked in potassium permanganate solution for 24 hours. Then, it was dried in an oven for 12 hours.
[0039] (2) The dried sample from (1) was placed in a ceramic boat and heated to 650°C at a heating rate of 5°C / min under a nitrogen atmosphere, and held for 180 min. Then, the product was washed with H2SO4 and water until pH=7. Finally, it was dried in an oven at 120°C to obtain hierarchical porous corn cob carbon (CPC).
[0040] (3) Nickel and cobalt metal salts were mixed with organic ligands (Ni,Co-MOF precursor) and CPC at a mass ratio of 3% in DMF solution at a ratio of 5:1. The mixture was then ultrasonicated at 70% ultrasonic power for 10 min in an ultrasonic cleaner to obtain a homogeneous mixed solution.
[0041] (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at 160°C for 24 hours.
[0042] (5) The product after the solvothermal reaction was naturally cooled to room temperature, centrifuged at 5000 rpm, washed four times with ethanol, and then vacuum dried at 40°C to prepare Ni,Co-MOF@CPC-3%. Physicochemical performance tests showed that the specific surface area of the prepared Ni,Co-MOF@CPC-3% material was 70.85 m². 2 g -1 Electrochemical performance test results show that: at 1Ag -1 At a current density of 3%, the specific capacitance of Ni,Co-MOF@CPC-3% is 1296.32 F g.-1 After 5000 GCD cycles, the capacitance retention of the Ni,Co-MOF@CPC-1% electrode was 81.3%.
[0043] Example 4:
[0044] (1) After washing, drying and crushing the waste corn cobs, a certain mass ratio of 4:1 corn cob powder was soaked in potassium permanganate solution for 36 hours. Then, it was dried in an oven for 24 hours.
[0045] (2) The dried sample from (1) was placed in a ceramic boat and heated to 650°C at a heating rate of 5°C / min under a nitrogen atmosphere, and held for 240 min. Then, the product was washed with H2SO4 and water until pH=7. Finally, it was dried in an oven at 120°C to obtain hierarchical porous corn cob carbon (CPC).
[0046] (3) Nickel and cobalt metal salts were mixed with organic ligands (Ni,Co-MOF precursor) and CPC at a mass ratio of 5% in DMF solution at a ratio of 3:1. The mixture was then ultrasonicated at 70% ultrasonic power for 10 min in an ultrasonic cleaner to obtain a homogeneous mixed solution.
[0047] (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at 160°C for 24 hours.
[0048] (5) The product after the solvothermal reaction was naturally cooled to room temperature, centrifuged at 5000 rpm, washed three times with ethanol, and then vacuum dried at 80°C to prepare Ni,Co-MOF@CPC-5%. Physicochemical performance tests showed that the specific surface area of the prepared Ni,Co-MOF@CPC-5% material was 229.46 m². 2 g -1 Electrochemical performance test results show that: at 1Ag -1 At a current density of 5%, the specific capacitance of Ni,Co-MOF@CPC-5% is 1438.12 F g. -1 After 5000 GCD cycles, the capacitance retention of the Ni,Co-MOF@CPC-1% electrode was 94.7%.
[0049] Example 5:
[0050] (1) After washing, drying and crushing the waste corn cobs, a certain mass ratio of corn cob powder of 5:1 was soaked in potassium permanganate solution for 24 hours. Then, it was dried in an oven for 24 hours.
[0051] (2) The dried sample from (1) was placed in a ceramic boat and heated to 750°C at a heating rate of 5°C / min under a nitrogen atmosphere and held for 180 min. The resulting product was then washed with H2SO4 and water until pH=7. Finally, it was dried in an oven at 120°C to obtain hierarchical porous corn cob carbon (CPC).
[0052] (3) Mix the nickel and cobalt metal salts with the organic ligand (Ni,Co-MOF precursor) and CPC at a mass ratio of 7% in DMF solution at a ratio of 5:1, and then sonicate them at 80% ultrasonic power for 15 minutes in an ultrasonic cleaner to obtain a homogeneous mixed solution.
[0053] (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at 180°C for 36 h.
[0054] (5) The product after the solvothermal reaction was naturally cooled to room temperature, centrifuged at 6000 rpm, washed four times with ethanol, and then vacuum dried at 80°C to prepare Ni,Co-MOF@CPC-7%. Physicochemical performance tests showed that the specific surface area of the prepared Ni,Co-MOF@CPC-7% material was 175.92 m². 2 g -1 Electrochemical performance test results show that: at 1Ag -1 At a current density of 7%, the specific capacitance of Ni,Co-MOF@CPC-7% is 1055.85 F g. -1 After 5000 GCD cycles, the capacitance retention of the Ni,Co-MOF@CPC-1% electrode was 84.6%.
[0055] Example 6:
[0056] (1) After washing, drying and crushing the waste corn cobs, a certain mass ratio of corn cob powder of 2:1 was soaked in potassium permanganate solution for 24 hours. Then, it was dried in an oven for 24 hours.
[0057] (2) The dried sample from (1) was placed in a ceramic boat and heated to 800°C at a heating rate of 5°C / min under a nitrogen atmosphere, and held for 180 min. Then, the product was washed with H2SO4 and water until pH=7. Finally, it was dried in an oven at 120°C to obtain hierarchical porous corn cob carbon (CPC).
[0058] (3) Nickel and cobalt metal salts were mixed with organic ligands (Ni,Co-MOF precursor) and CPC at a mass ratio of 20% in DMF solution at a ratio of 7:1. The mixture was then ultrasonicated at 100% ultrasonic power for 20 min in an ultrasonic cleaner to obtain a homogeneous mixed solution.
[0059] (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at 150°C for 12 hours.
[0060] (5) The product after the solvothermal reaction was naturally cooled to room temperature and centrifuged at 6000 rpm. It was then washed four times with ethanol and vacuum dried at 80°C to prepare Ni,Co-MOF@CPC-10%. Physicochemical performance tests showed that the specific surface area of the prepared Ni,Co-MOF@CPC-10% material was 222.94 m². 2 g -1 Electrochemical performance test results show that: at 1Ag -1 At a current density of 10%, the specific capacitance of Ni,Co-MOF@CPC-10% is 685.49 F g. -1 After 5000 GCD cycles, the capacitance retention of the Ni,Co-MOF@CPC-1% electrode was 87.5%.
[0061] Example 7:
[0062] (1) After washing, drying and crushing the waste corn cobs, a certain mass ratio of 4:1 corn cob powder was soaked in potassium permanganate solution for 36 hours. Then, it was dried in an oven for 24 hours.
[0063] (2) The dried sample from (1) was placed in a ceramic boat and heated to 650°C at a heating rate of 5°C / min under a nitrogen atmosphere, and held for 240 min. Then, the product was washed with H2SO4 and water until pH=7. Finally, it was dried in an oven at 120°C to obtain hierarchical porous corn cob carbon (CPC).
[0064] (3) Nickel and cobalt metal salts were mixed with organic ligands (Ni,Co-MOF precursor) and CPC at a mass ratio of 5% in DMF solution at a ratio of 5:1. The mixture was then ultrasonicated at 70% ultrasonic power for 10 min in an ultrasonic cleaner to obtain a homogeneous mixed solution.
[0065] (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at 160°C for 24 hours.
[0066] (5) The product after the solvothermal reaction was naturally cooled to room temperature and centrifuged at 5000 rpm. It was then washed three times with ethanol and vacuum dried at 80 °C to prepare Ni,Co-MOF@CPC-5%. Ni,Co-MOF@CPC-5% and CPC were used as positive and negative electrodes respectively, combined with a 2MKOH-PVA gel electrode to assemble an asymmetric supercapacitor (Ni,Co-MOF@CPC-5 / / CPC). Electrochemical test results showed that at 1 Ag... -1 At a current density of [value missing], the specific capacitance of Ni,Co-MOF@CPC-5 / / CPC is 197.65 F g. -1 Its highest energy density and power density are Wh / kg, respectively. -1 and 7500Wkg -1 Furthermore, after 10,000 GCD cycles, the capacitance retention of Ni,Co-MOF@CPC-5 / / CPC remains at 87%.
Claims
1. A method for preparing biochar-anchored sea urchin-like Ni,Co-MOF, characterized in that, The method is performed in the following steps: (1) The waste corn cobs are washed, dried and crushed to obtain corn cob powder. A certain mass ratio of corn cob powder is soaked in potassium permanganate solution for a certain time. Then, it is dried in an oven for 12-24 hours to obtain the dried sample. The corn cob powder in step (1) is soaked in potassium permanganate solution for a certain time, wherein the mass ratio of corn cob powder to potassium permanganate is 1:0 to 1:7 and the soaking time is 12-48 hours. (2) Place the dried sample from (1) into a ceramic boat and heat it to a certain temperature at a heating rate of 5℃ / min under a nitrogen atmosphere. Hold it for 60-360 min. Then, wash the obtained product with H2SO4 and water until pH=7. Finally, dry it in an oven at 120℃ to obtain a hierarchical porous corn cob carbon CPC. (3) A certain proportion of nickel and cobalt metal salts and organic ligands, which are Ni,Co-MOF precursors, are mixed with CPC in a DMF solution at a certain mass ratio. The mixture is then ultrasonicated for 5 to 50 minutes at 40 to 100% ultrasonic power in an ultrasonic cleaner to obtain a homogeneous mixed solution. The mass ratio of nickel and cobalt metal salts in the Ni,Co-MOF precursor is 1:1 to 9:1, and the mass ratio of CPC to Ni,Co-MOF precursor is 1% to 50%. (4) Transfer the mixed solution to a high-pressure reactor with polytetrafluoroethylene built-in, place it in a homogeneous reactor, and solvothermal reaction at a certain temperature for a period of time; the solvothermal temperature of step (4) is 80-240℃, and the solvothermal reaction time is 3-48h; (5) The product after the solvothermal reaction was naturally cooled to room temperature, centrifuged at a speed of 2500-6000 rpm, washed with ethanol 3-5 times, and dried at 35-120℃ to prepare corn cob porous carbon anchored sea urchin-like Ni,Co-MOF.
2. A biochar anchoring method for sea urchin-like Ni,Co-MOF, characterized in that, The method described in claim 1 for preparing biochar-anchored sea urchin-like Ni,Co-MOF was used.
3. The biochar anchoring of sea urchin-like Ni,Co-MOF as described in claim 2, characterized in that, The biochar-anchored sea urchin-like Ni,Co-MOF@CPC is used as an electrode material for the positive electrode of supercapacitors.