The Fabrication Of MOFs-derived Carbon-based Materials And Their Electrochemical Performances

Supercapacitors are one of the important devices for energy conversion and storage.Electrode materials are the direct energy storage part of capacitors,which plays a decisive role in capacitor performance.Research on high-performance,low-cost,and green electrode materials is crucial for the development of capacitors.Due to defects such as poor electrical conductivity and low hydrophilicity of traditional carbon-based materials,the interfacial resistance between electrodes and electrolyte in aqueous electrolyte increases,which hinders the application of traditional carbon-based materials in capacitor applications.In this thesis,P doped MOFs based porous carbon materials were synthesized using MOFs as precursors and phytic acid as phosphorus sources,and their physical and chemical properties were studied.（1）In the ZIF-8 system,phytic acid was introduced as a phosphorus source to prepare P doped porous carbon materials（PC8-X-Y,where X represents the amount of phytic acid and Y represents the carbonization temperature）.The effects of P doping content and different carbonization temperatures on the morphology,structure,and capacitive properties of carbon materials were systematically studied.BET characterization shows that PC8-50-900 is mainly mesoporous and has a high specific surface area(836.06 m2g^-1).The specific capacity is 200 F g^-1 at a current density of 1 A g^-1,and the capacity retention rate is 100.03%after 5000 cycles,showing good stability.The results show that the porous carbon material prepared by doping P atoms with ZIF-8 as a precursor has good capacitive properties.（2）Based on the monoatomic metal centers of MOFs,the capacitive properties of MOFs derived carbon materials（PC2-X-900）with dual atomic metal centers of Zn and Co were studied.The prepared carbon material（PC2-X-900）has a three-dimensional porous structure dominated by mesopores,with a surface area of up to 1125.21 m2g^-1.The material exhibits double layer capacitance within a voltage window of-1～0 V.The content of P doping affects the specific capacitance of the electrode material.When the content of P doping is 100μL,the maximum specific capacitance of the electrode material PC2-100-900is 351 F g^-1,which is 100 F g^-1 higher than that of the electrode material PC2-0-900 without P doping.Moreover,the electrode material exhibits good cyclic stability and maintains a specific capacitance of 94.95%after 5000 cycles,making it an ideal electrode material.（3）Based on the previous research work,P,N,Co doped Cu/C composites（CZF2-X-900）were prepared using Zn,Cu diatomic metal MOFs as precursors.CZF2-X-900 has a three-dimensional layered structure with Cu O clusters attached to its surface,so there are redox peaks in electrochemical testing,and the material exhibits a certain degree of pseudocapacitance.At a current density of 1 A g^-1,the material CZF2-100-900 exhibits a specific capacitance of 457 F g^-1,which is higher than that of carbon materials derived from monometallic and zinc cobalt bimetallic MOFs.After 5000 cycles,the capacity retention rate is 98.2%,showing excellent electrode material potential.