阅读说明：本技术 一种原位杂化的配位聚合物衍生多孔花状Co2P2O7/C复合材料的制备方法 (In-situ hybridized coordination polymer derived porous flower-like Co2P2O7Preparation method of/C composite material ) 是由 肖振宇 张家鑫 邓英 王福鹏 王磊 于 2020-06-23 设计创作，主要内容包括：本发明公开一种原位杂化的配位聚合物衍生多孔花状Co<Sub>2</Sub>P<Sub>2</Sub>O<Sub>7</Sub>/C复合材料的制备方法,首先将质量比为1:1.3的苯膦酸和六水合硝酸钴分别溶入无水乙醇和乙二醇体积比为2:3的混合溶剂中,然后,在150℃的条件下反应12-48小时,制备了花状的苯基膦酸钴配位聚合物[Co(PhPO<Sub>3</Sub>)]前驱体；称取200mg Co(PhPO<Sub>3</Sub>),在氮气氛围中,以2℃min<Sup>-1</Sup>的升温速度从常温升至煅烧所需的温度(600-1000℃),并保持两小时,制备目标产物原位杂化的配位聚合物衍生多孔花状Co<Sub>2</Sub>P<Sub>2</Sub>O<Sub>7</Sub>/C复合材料(Co<Sub>2</Sub>P<Sub>2</Sub>O<Sub>7</Sub>/C-X；其中X为煅烧的温度)。本发明提供的原位杂化的配位聚合物衍生多孔花状Co<Sub>2</Sub>P<Sub>2</Sub>O<Sub>7</Sub>/C复合材料的制备策略,实现了纳米Co<Sub>2</Sub>P<Sub>2</Sub>O<Sub>7</Sub>颗粒与纳米石墨化碳的原位杂化,有效的增强了材料的导电性和循环稳定性,具有良好的超级电容器应用潜能。(The invention discloses an in-situ hybridized coordination polymer derived porous flower-like Co 2 P 2 O 7 Firstly, respectively dissolving phenylphosphonic acid and cobalt nitrate hexahydrate with the mass ratio of 1:1.3 into a mixed solvent with the volume ratio of anhydrous ethanol to ethylene glycol of 2:3Then, reacted at 150 ℃ for 12-48 hours to prepare flower-like cobalt phenylphosphonate coordination polymer [ Co (PhPO) 3 )]A precursor; weighing 200mg Co (PhPO) 3 ) In a nitrogen atmosphere at 2 ℃ for min ‑1 The temperature rise speed is increased from normal temperature to the temperature (600-1000 ℃) required by calcination and is kept for two hours, and the target product, namely the in-situ hybridized coordination polymer, is prepared to derive the porous flower-shaped Co 2 P 2 O 7 Composite material/C (Co) 2 P 2 O 7 C-X; wherein X is the temperature of calcination). The invention provides an in-situ hybridized coordination polymer derived porous flower-like Co 2 P 2 O 7 The preparation strategy of the/C composite material realizes the preparation of nano Co 2 P 2 O 7 The in-situ hybridization of the particles and the nano graphitized carbon effectively enhances the conductivity and the cycling stability of the material, and has good application potential of the super capacitor.)

1. In-situ hybridized coordination polymer derived porous flower-like Co₂P₂O₇The preparation method of the/C composite material is characterized by comprising the following steps:

(1)Co(PhPO₃) Preparing a precursor: respectively dissolving phenylphosphonic acid and cobalt nitrate hexahydrate with the mass ratio of 1:1.3 into a mixed solvent with the volume ratio of anhydrous ethanol to ethylene glycol of 2:3, and performing ultrasonic dispersion for 30 minutes to uniformly mix the materials and form a uniform solution. Then transferring the mixture into a high-pressure reaction kettle, and reacting for 12-48 hours at the temperature of 150 ℃.

(2)Co₂P₂O₇Preparation of/C hybrid material: weighing 200mg Co (PhPO)₃) Placing the precursor in a porcelain boat, and placing the porcelain boatPlacing into a tube furnace, and heating at 2 deg.C for 2 min in nitrogen atmosphere^-1The temperature rise speed is increased from normal temperature to the temperature (600-1000 ℃) required by calcination, and the temperature is kept for two hours, so that the target product, namely the in-situ hybridized coordination polymer derived porous flower-shaped Co is prepared₂P₂O₇Composite material/C (Co)₂P₂O₇C-X; wherein X is the temperature of calcination).

2. The method of claim 1, wherein: the solvothermal reaction time in the step (1) is 24 hours.

3. The method of claim 1, wherein: the calcining temperature of the step (2) is 900 ℃.

4. The method of claim 1, wherein: the in-situ hybridized coordination polymer obtained in the step (2) is derived into porous flower-like Co₂P₂O₇the/C composite material is 1A g^-1The specific capacity under the current density reaches 248.2-349.6F g^-1Of which the optimum sample Co₂P₂O₇C-900 at 2A g^-1The capacity retention rate of the lithium ion battery reaches 97.33% after 3000 cycles.

5. The method of claim 1, wherein: the in-situ hybridized coordination polymer obtained in the step (2) is derived into porous flower-like Co₂P₂O₇the/C composite material can be assembled with a graphene-based supercapacitor negative electrode material to form a two-electrode supercapacitor, and the volume of the two-electrode supercapacitor is 0.375 kW.kg^-1The energy density is up to 21.9 Wh.kg at power density^-1。

Technical Field

The invention belongs to the technical field of new functional materials, and particularly relates to in-situ hybridized cobalt phenylphosphonate coordination polymer-based porous flower-shaped Co₂P₂O₇A controllable preparation method of a/C composite material and an electrochemical energy storage application thereof.

Background

With the rapid development of electric vehicles and mobile electronic devices, the conventional energy storage device cannot meet the increasing production requirements of people, and therefore, it is very important to develop a safe, efficient and convenient energy storage device. As a new electric energy storage device, the super capacitor has the advantages of long cycle life, fast charge and discharge rate, high safety factor, high power density, and the like, and thus has attracted extensive attention in the scientific field. As is well known, supercapacitors are largely classified into electric double layer supercapacitors and pseudo-capacitive supercapacitors, depending on the charge storage mechanism. The pseudo-capacitor super capacitor realizes charge storage by means of redox reaction between electrode materials and electrolyte solution, so that the redox reaction activity between the pseudo-capacitor super capacitor and the electrolyte solution is improved by designing and adjusting some suitable electrode materials, and the pseudo-capacitor super capacitor is one of strategies for improving the energy storage performance of the pseudo-capacitor super capacitor.

Transition metal phosphates (TMPs, M)_xP_yO_zM＝Co²⁺,Ni²⁺,Mn²⁺Et al.), is a mixture of phosphate/pyrophosphate/phosphorus anion and metal ionA class of materials with open frameworks that are structurally stable. With Co₂P₂O₇For example, the material has the advantages of excellent redox activity, abundant natural reserves, environmental friendliness and the like, and is one of potential candidate electrode materials. However, the electron conductivity of the material itself is low, limiting its energy storage performance. Therefore, the design and construction of the composite material of TMPs and the high-conductivity material, especially the nano-scale composite and in-situ doping, are effective ways for solving the intrinsic conductivity defect of the material and improving the performance of the capacitor.

Coordination polymers are polymer network structures formed by connecting metal ions and organic ligands with each other in a coordination bond in a self-assembly mode. The preparation method has the advantages of various structures and compositions, ultrahigh specific surface area, abundant pore structures, adjustable pore diameters and the like, and is an ideal precursor for preparing the electrode material of the supercapacitor. In addition, the coordination polymer has a unique metal-organic hybrid structure, so that in-situ hybridization of inorganic nanoparticles and nano carbon can be realized, the electronic conductivity of the composite material is enhanced, and the dynamic process of electrochemical reaction is promoted. Therefore, the coordination polymer precursor with a specific morphology is designed and prepared, and the in-situ carbon-doped nano transition metal phosphate is constructed through a controllable treatment process, so that the intrinsic defects of the transition metal phosphate can be obviously improved, and the performance of the supercapacitor is improved.

Disclosure of Invention

The invention provides an in-situ hybridization strategy, which is regulated and controlled by a precise preparation process and is based on flower-like cobalt phenylphosphonate coordination polymer [ Co (PhPO)₃)]The unique coordination skeleton structure of the precursor maintains Co (PhPO) through a high-temperature thermal conversion process₃) Framework of precursor, preventing Co₂P₂O₇Excessive agglomeration of nano particles realizes nano Co₂P₂O₇The in-situ hybridization of the particles and the nano graphitized carbon effectively enhances the specific capacity and the cycling stability of the cobalt pyrophosphate.

The invention provides an in-situ hybridized coordination polymer derived porous flower-like Co₂P₂O₇The preparation method of the/C composite material can be realized by the following technical route:

(1)Co(PhPO₃) Preparing a precursor: respectively dissolving phenylphosphonic acid and cobalt nitrate hexahydrate with the mass ratio of 1:1.3 into a mixed solvent with the volume ratio of anhydrous ethanol to ethylene glycol of 2:3, and performing ultrasonic dispersion for 30 minutes to uniformly mix the materials and form a uniform solution. Then transferring the mixture into a high-pressure reaction kettle, and reacting for 12-48 hours at the temperature of 150 ℃; the reaction time is 12-48 hours for the purpose of reacting Co (PhPO)₃) The material can be fully crystallized and mineralized, the material with too short reaction time has smaller crystallinity and size, and the material with increased reaction time has gradually increased crystallinity and size.

(2)Co₂P₂O₇Preparation of/C hybrid material: weighing 200mg Co (PhPO)₃) Placing the precursor in a porcelain boat, placing the porcelain boat in a tube furnace, and heating at 2 deg.C for min in nitrogen atmosphere^-1The temperature rise speed is increased from normal temperature to the temperature (600-1000 ℃) required by calcination, and the temperature is kept for two hours, so that the target product, namely the in-situ hybridized coordination polymer derived porous flower-shaped Co is prepared₂P₂O₇Composite material/C (Co)₂P₂O₇C-X; wherein X is the temperature of calcination); here, different calcination temperatures may affect the morphology, crystallinity, phase transition degree, etc. of the material, when the temperature is too low, the material cannot be completely converted into cobalt pyrophosphate and graphitized carbon, and when the temperature is too high, the flower-like morphology of the precursor is difficult to maintain, and the nano flower-like structure of the material may be damaged.

As a further feature of the present invention: the solvothermal reaction time of the step (1) is 24 hours, and the obtained Co (PhPO)₃) The material presents a flower-like appearance stacked by a layered structure; although the solvothermal reaction gave Co (PhPO) at different times₃) The crystallinity of (a) is different from the nano-size, and the same is true for the subsequent thermal conversion process of the invention, but the properties are different.

As a further feature of the present invention: the calcination temperature of the step (2) is 900 ℃ and is named as Co₂P₂O₇/C-900。

As a further feature of the present invention: the in-situ hybridized coordination polymer obtained in the step (2) is derived into porous flower-like Co₂P₂O₇the/C composite material has good super capacitor performance and is 1Ag under the condition of a three-electrode system^-1The specific capacity under the current density reaches 248.2-349.6F g^-1Of which the optimum sample Co₂P₂O₇C-900 at 2Ag^-1The capacity retention rate of the lithium ion battery reaches 97.33% after 3000 cycles, and the lithium ion battery shows excellent cycle stability.

As a further feature of the present invention: porous flower-like Co derived from coordination polymer by in-situ hybridization in step (2)₂P₂O₇the/C composite material can be assembled with a graphene-based supercapacitor negative electrode material to form a two-electrode supercapacitor, and the volume of the two-electrode supercapacitor is 0.375 kW.kg^-1The energy density is up to 21.9 Wh.kg at power density^-1。

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

porous flower-like Co derived from in-situ hybridized coordination polymer prepared by the invention₂P₂O₇A/C composite material based on an inorganic 2D [ Co (-PO) coated with an organic benzene ring₃)(H₂O)₂]_nLayer-composed flower-like structure cobalt phenylphosphonate coordination polymer [ Co (PhPO)₃)]And (3) precursor. Converting the 2D inorganic layer in the precursor into Co by a high-temperature calcination process in a nitrogen atmosphere₂P₂O₇Nano particles, and simultaneously, the organic benzene ring on the surface of the 2D inorganic layer is converted into graphitized carbon in situ to cover the surface of the inorganic layer to form porous flower-shaped Co₂P₂O₇a/C composite material. Wherein, the calcination is carried out in the nitrogen atmosphere, oxygen is isolated, and organic benzene rings in the material can be protected from oxidation. The formation of in-situ nano-scale graphitized carbon can improve the electronic conductivity and the cycling stability of the material and simultaneously prevent Co₂P₂O₇Excessive agglomeration of the nano particles provides more electrochemical active sites, and the specific capacity of the material is improved. Therefore, by this inventionPorous flower-like Co derived from in-situ hybridized coordination polymer prepared by open method₂P₂O₇the/C composite material has more excellent super capacitor performance, particularly, the performance is 1A g^-1The specific capacity of the alloy reaches 248.2-349.6F g under the current density^-1Of which the optimum sample Co₂P₂O₇C-900 at 2Ag^-1The capacity retention rate of the lithium ion battery reaches 97.33% after 3000 cycles, and the lithium ion battery shows excellent cycle stability.

Description of the drawings:

FIG. 1: co (PhPO) in example 1₃) Scanning electron microscope images of the precursor;

FIG. 2: co (PhPO) in example 1₃) A powder X-ray diffraction pattern of the precursor;

FIG. 3: co in example 1₂P₂O₇A powder X-ray diffraction pattern of/C-900;

FIG. 4: co in example 1₂P₂O₇A scanning electron micrograph of/C-900;

FIG. 5: co in example 1₂P₂O₇A projection electron micrograph of/C-900;

FIG. 6: co in example 1₂P₂O₇An X-ray photoelectron spectrum of/C-900;

FIG. 7: co in example 1₂P₂O₇A constant-current charge-discharge curve diagram of the/C-900 at different sweeping speeds;

FIG. 8: co in example 1₂P₂O₇The cycle stability test curve of the/C-900 in a three-electrode system;

FIG. 9: co in example 2₂P₂O₇-900 constant current charge and discharge curves at different sweep rates;

FIG. 10: co in example 3₂P₂O₇A constant-current charge-discharge curve diagram of the/C-600 at different sweeping speeds;

FIG. 11: co in example 4₂P₂O₇A constant-current charge-discharge curve diagram of/C-700 at different sweeping speeds;

FIG. 12: practice ofCo in example 5₂P₂O₇A constant-current charge-discharge curve diagram of/C-800 at different sweeping speeds;

FIG. 13: co in example 6₂P₂O₇A constant-current charge-discharge curve diagram of the/C-1000 at different sweep rates.

Detailed Description

The technical features of the present invention will be described below with reference to specific experimental schemes and drawings, but the present invention is not limited thereto. The test methods described in the following examples are all conventional methods unless otherwise specified; the apparatus and materials are commercially available, unless otherwise specified.