阅读说明：本技术 一种高性能NiCo2O4/C复合材料的制备方法 (High-performance NiCo2O4Preparation method of/C composite material ) 是由 张春勇 黄琳娜 刘海涛 张颖 赵渝越 苏蕾 李健宁 张译文 于 2020-06-16 设计创作，主要内容包括：本发明公开一种高性能NiCo<Sub>2</Sub>O<Sub>4</Sub>/C复合材料的制备方法,以钴盐、镍盐、尿素和炭化的生物质炭材料为原料,以水热法为辅助合成高性能NiCo<Sub>2</Sub>O<Sub>4</Sub>/C,制备流程少,简单易操作,投资成本低,用该方法制备的NiCo<Sub>2</Sub>O<Sub>4</Sub>/C复合材料呈线状或针状,可加大材料的比表面积,暴露出更多的活性位点,NiCo<Sub>2</Sub>O<Sub>4</Sub>分散在生物炭表面,可解决NiCo<Sub>2</Sub>O<Sub>4</Sub>易团聚、易粉化的问题,使其具备出色的电化学性能,有望成为性能优良的超级电容器电极材料；同时,本发明以生物质炭材料作为炭源,满足低炭环保的要求。(The invention discloses a high-performance NiCo 2 O 4 The preparation method of the/C composite material comprises the steps of taking cobalt salt, nickel salt, urea and carbonized biomass charcoal material as raw materials, and taking a hydrothermal method as an auxiliary method to synthesize high-performance NiCo 2 O 4 /C, less preparation process, simple and easy operation, low investment cost, NiCo prepared by the method 2 O 4 the/C composite material is in a linear or needle shape, the specific surface area of the material can be increased, more active sites are exposed, and NiCo 2 O 4 Dispersed on the surface of the charcoal, can solve NiCo 2 O 4 The material is easy to agglomerate and pulverize, so that the material has excellent electrochemical performance and is expected to become a super capacitor electrode material with excellent performance; meanwhile, the biomass charcoal material is used as a charcoal source, so that the low-charcoal environmental protection requirement is met.)

1. High-performance NiCo₂O₄The preparation method of the/C composite material is characterized by comprising the following steps:

(1) mixing cobalt salt and deionized water to obtain a solution A;

(2) respectively weighing nickel salt and urea in a certain molar ratio, putting the nickel salt and the urea into the mixed solution A obtained in the step one, and performing ultrasonic treatment to obtain a mixed solution B;

(3) after the biomass charcoal material is carbonized, transferring the carbonized biomass charcoal material and the solution B obtained in the step (2) to a stainless steel hydrothermal kettle with a polytetrafluoroethylene lining for constant-temperature hydrothermal reaction, after the reaction is finished, cooling the reaction kettle to room temperature, taking out the rice straws, and drying the rice straws at the room temperature for later use;

(4) taking out the biomass charcoal material obtained in the step (3), placing the biomass charcoal material in a porcelain boat, and introducing O₂Conditions of (2)Calcining at 200-500 ℃ for 1-6 hours to prepare NiCo₂O₄a/C composite material.

2. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that in the step (2), the molar ratio of the cobalt salt to the nickel salt to the urea is 1 (0.2-20) to 1-50.

3. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that in the step (1), the cobalt salt is cobalt acetate tetrahydrate, cobalt chloride or cobalt nitrate hexahydrate.

4. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that in the step (2), the nickel salt is nickel sulfate hexahydrate or nickel nitrate hexahydrate.

5. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that in the step (2), the ultrasonic treatment frequency is 50-100 kHz, and the ultrasonic treatment time is 30-60 min.

6. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that in the step (2), the temperature of the solution in the ultrasonic treatment process is not more than 40 ℃.

7. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that in the step (3), the temperature for carrying out the constant-temperature hydrothermal reaction is 100-200 ℃, and the hydrothermal reaction time is 3-48 h.

8. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that in the step (3), the biomass charcoal material is charcoalThe carbonization process is carried out under the condition of introducing nitrogen, the carbonization temperature is 500-900 ℃, and the carbonization time is 4-8 h.

9. The high performance NiCo of claim 1₂O₄The preparation method of the/C composite material is characterized in that the selection range of the biomass charcoal material comprises straw and bamboo chips.

Technical Field

The invention relates to the field of material synthesis, in particular to high-performance NiCo₂O₄A preparation method of the/C composite material.

Background

The energy strategy is one of the important subjects of sustainable development, and the energy storage device is an important component in the energy strategy. The super capacitor is used as a novel green energy storage device, and has wide application prospect in the fields of new energy technology, electric energy weapons, electric automobiles and the like. The super capacitor has larger power density and can provide enough instantaneous power for braking of the vehicle. In addition, the super capacitor can be applied to the aspects of military industry, material transportation, electronic storage devices and the like, and has wide prospects.

The supercapacitor is usually made of a metal oxide such as Co having a very high specific capacity₃O₄，Fe₂O₃，ZnO，NiO，SnO₂，TiO₂And AB₂O₄(e.g., MnCo)₂O₄，NiCo₂O₄，ZnCo₂O₄，FeCo₂O₄Etc.) as a negative electrode material; among the various metal oxides, NiCo₂O₄Not only has the advantages of high theoretical capacitance, low cost, good electrochemical activity, large capacity and the like, but also has the advantages of higher theoretical capacitance, lower cost, higher electrochemical activity, larger capacity and the like than Co₃O₄Or other single metal oxides, have better conductivity and low activation energy for electron transfer, which results in NiCo₂O₄Becoming a potential anode material for lithium ion batteries. However, NiCo₂O₄At high discharge ratesThe test shows poor cycle performance and reversible capacity when charging and discharging tests are carried out, and NiCo₂O₄The main problem of the cathode material is that the volume change is too obvious in the process of lithium intercalation and deintercalation, and the pulverization phenomenon is easy to occur, so that the electrochemical cyclicity of the material is not ideal, and further practical application of the material is limited.

Later, through research of related personnel, NiCo₂O₄The improvement of the shape is to effectively improve NiCo₂O₄The performance approaches, such as Chinese patents CN106938859A, CN104701036A and CN106882845A, respectively prepare tubular, hierarchical flower-shaped and mesoporous sea urchin-shaped NiCo₂O₄NiCo prepared by such a method₂O₄The shape and size of the electrode are more uniform, the electrochemical performance is obviously improved, but the electrode needs to be further strengthened when being applied to the field of supercapacitors.

The biomass charcoal material is a material which has high stability, strong adsorption performance, good chemical stability, good conductivity, low cost and easy obtainment. If the biomass charcoal material in the agricultural and forestry waste is used as the raw material to manufacture the electrode material of the super capacitor, the volume expansion effect of the material in the charging and discharging process can be greatly relieved, and the chemical electricity storage performance is further improved. Great soup (& lt & ltNiCo & gt)₂O₄Preparation of/C composite electrode material and performance of super capacitor) synthesized nano NiCo by chemical coprecipitation method₂O₄The structure and the appearance of a sample are characterized, and the NiCo prepared by the method₂O₄The specific capacitance of the electrode material/C can be as high as 290.49F/g, and the performance is greatly improved compared with the prior art. However, the preparation steps of the method are complex, the operability needs to be further simplified for convenience of implementation and mass production, and the overall stability and electrochemical performance of the material still have a large development space with the continuous improvement of the development requirement of the super capacitor.

Therefore, there is a need to develop a more direct and efficient NiCo₂O₄The preparation method can change the stability and electrochemical performance of the product by regulating and controlling the shapeIs more superior to the development trend of the super capacitor at present.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a high-performance NiCo₂O₄Method for producing/C composite materials, so that NiCo₂O₄Can be dispersed on the surface or in the pore canal of the biological carbon to solve the problem of NiCo₂O₄The problem of easy agglomeration and easy pulverization lays a foundation for the commercial application of the electrode material of the super capacitor.

The invention is realized by the following technical scheme: high-performance NiCo₂O₄The preparation method of the/C composite material comprises the following steps:

(1) mixing cobalt salt and deionized water to obtain a solution A;

(2) respectively weighing nickel salt and urea in a certain molar ratio, putting the nickel salt and the urea into the mixed solution A obtained in the step one, and performing ultrasonic treatment to obtain a mixed solution B;

(3) after the biomass charcoal material is carbonized, transferring the carbonized biomass charcoal material and the solution B obtained in the step (2) to a stainless steel hydrothermal kettle with a polytetrafluoroethylene lining for constant-temperature hydrothermal reaction, after the reaction is finished, taking out the biomass charcoal material after the reaction kettle is cooled to room temperature, and drying the biomass charcoal material at room temperature for later use;

(4) taking out the biomass charcoal material obtained in the step (3), placing the biomass charcoal material in a porcelain boat, and introducing O₂Calcining at 200-500 ℃ for 1-6 hours to prepare NiCo₂O₄a/C composite material.

Further, the biomass charcoal material comprises biomass materials including straw and bamboo chips.

Furthermore, in the step (2), the molar ratio of the cobalt salt, the nickel salt and the urea is 1 (0.2-20) to 1-50.

Further, in the step (1), the cobalt salt is cobalt acetate tetrahydrate, cobalt chloride or cobalt nitrate hexahydrate.

Further, in the step (2), the nickel salt is nickel sulfate hexahydrate or nickel nitrate hexahydrate.

Further, in the step (2), the ultrasonic treatment frequency is 50-100 kHz, and the ultrasonic treatment time is 30-60 min.

Further, in the step (2), the temperature of the solution during the ultrasonic treatment is not more than 40 ℃.

Further, in the step (3), the temperature for carrying out the constant temperature hydrothermal reaction is 100-200 ℃, and the hydrothermal reaction time is 3-48 h.

Further, in the step (3), the carbonization process of the biomass charcoal material is carried out under the condition of introducing nitrogen, the carbonization temperature is 500-900 ℃, and the carbonization time is 4-8 h.

The invention has the beneficial effects that:

1. high-performance NiCo synthesized by the method disclosed by the invention₂O₄the/C composite material can improve the overall stability of the material, and the prepared NiCo₂O₄the/C composite material is in a linear or needle shape, the specific surface area of the material can be increased, more active sites are exposed, and NiCo₂O₄Dispersed on the surface and in the pore canal of the biological carbon, can solve NiCo₂O₄The material is easy to agglomerate and pulverize, and the electrochemical performance of the material can be effectively improved, so that the material is expected to become a super capacitor electrode material with excellent performance;

2. the invention adopts a one-step hydrothermal method to obtain linear NiCo₂O₄The preparation process of the/C composite material is less, the operation is simple, and the implementation is easy;

3. the invention takes the straw biomass charcoal material as the raw material, and the straw has the characteristics of low price, easy obtainment, environmental protection and sustainability, thereby laying a foundation for the resource utilization of agricultural and forestry wastes.

Drawings

FIG. 1 is a NiCo product obtained in comparative example 1₂O₄SEM topography of;

FIG. 2 shows NiCo obtained in comparative example 1₂O₄An XRD pattern of (a);

FIG. 3 is a schematic representation of a wire-like NiCo obtained in example 1₂O₄SEM topography of the/C composite material;

FIG. 4 is a schematic representation of a wire-like NiCo obtained in example 1₂O₄XRD pattern of the/C composite material;

FIG. 5 is an SEM image of carbonized rice straw (calcined at 650 ℃ for 3h under the condition of introducing nitrogen gas);

FIG. 6 is an XRD (XRD) pattern of carbonized rice straw (calcined at 650 ℃ for 3h under the condition of introducing nitrogen gas);

FIG. 7 is a schematic representation of the needle-like NiCo obtained in example 5₂O₄SEM topography of/biomass bamboo chip composite material;

FIG. 8 is a schematic representation of the needle-like NiCo obtained in example 5₂O₄XRD pattern of the biomass bamboo chip composite material;

FIG. 9 is an SEM photograph of carbonized bamboo chips (calcined at 650 ℃ for 3 hours under the condition of introducing nitrogen gas);

FIG. 10 is an XRD pattern of carbonized bamboo chips (calcined at 650 ℃ for 3 hours under the condition of introducing nitrogen gas);

FIG. 11 shows carbonized straw, NiCo prepared in comparative example 1₂O₄And wire form NiCo obtained in example 1₂O₄Cyclic voltammogram of/C;

FIG. 12 is a constant current charge and discharge diagram of three materials, wherein a is a linear NiCo prepared in example 1₂O₄A constant current charge-discharge diagram of C, a constant current charge-discharge diagram of carbonized straw b, and NiCo prepared in comparative example 1C₂O₄Constant current charge-discharge diagram of (1);

FIG. 13 shows the charred straw, NiCo from comparative example 1₂O₄And wire form NiCo obtained in example 1₂O₄Impedance plot of/C;

FIG. 14 shows NiCo obtained in comparative example 1₂O₄Needle-like NiCo obtained in example 5₂O₄A circulating voltammogram of the biomass bamboo chip composite material and the carbonized bamboo chips;

FIG. 15 is a constant current charge and discharge diagram of three materials, wherein a is needle-like NiCo obtained in example 5₂O₄Constant current charging and discharging diagram of biomass bamboo sheet composite material, b constant current charging and discharging diagram of carbonized bamboo sheet, and c NiCo prepared in comparative example 1₂O₄Constant current charge-discharge diagram of (1);

FIG. 16 is a NiCo sample obtained in comparative example 1₂O₄Needle-like NiCo obtained in example 5₂O₄Impedance diagrams of/biomass bamboo chip composite materials and carbonized bamboo chips.

Detailed Description

The following detailed description of the preferred embodiments of the present invention is provided to enable those skilled in the art to more readily understand the advantages and features of the present invention, and to clearly and unequivocally define the scope of the present invention.