Study On The Performance Of Conductive Metal-organic Framework Material Ni₃(HITP)₂ In Aqueous Electrolyte

As a new type of energy storage device,supercapacitors have been well applied in the fields of microgrid,electronic equipment,power transportation,etc.However,the low energy density restricts its development,so it is urgent to find suitable electrode materials.metal-organic framework material is a kind of porous crystal with high specific surface area and adjustable pore size,which is very suitable as electrode material of supercapacitor to further increase its energy density.At present,there are few researches on improving the capacitance performance of conductive metal-organic framework materials.Through better synthesis schemes,materials with better structural characteristics can be prepared,thereby improving the conductivity and capacitance performance of the materials,which can also improve energy density of supercapacitors based on metal-organic framework materials.In this study,a metal-organic framework Ni₃(HITP)₂ with good electrical conductivity and capacitance performance is used as the research object to explore the relationship among preparation scheme,structural characteristics and capacitance performance thereby study the method to improve the capacitance performance of conductive metal-organic framework materials.According to the hydrothermal preparation scheme of Ni₃(HITP)₂,three derivatized preparation schemes were designed,and the preparation schemes were modified in three aspects:synthesis method,reaction temperature and reaction solvent.Through X-ray diffraction technology,scanning electron microscope,nitrogen adsorption curve and other characterization methods,it is observed that the pore size distribution of the ultrasonic solution is the most concentrated,and it has larger and uniform clusters and columnar structures.The room temperature solution has the largest specific surface area,and its clusters phenomenon is not obvious,the columnar structure is longer and more dispersed.The crystallinity of the mixed solvent solution is the best,and the cluster phenomenon is manifested as a cluster,which is composed of smaller particles.Electrochemical tests were carried out on Ni₃(HITP)₂ materials prepared by four schemes including the hydrothermal scheme.It was found that the ultrasonic scheme had the best mass specific capacitance of 127.64 F g^-1,and the hydrothermal scheme and the room temperature scheme also had high capacitance.Comparing the structural parameters of these three materials,it is easy to find that they have a higher specific surface area or a more concentrated pore size distribution.Comparing Ni₃(HITP)₂ materials with commercial porous carbon materials,it is found that the mass specific capacitance and area specific capacitance of Ni₃(HITP)₂ are?2 times and?5 times that of commercial carbon materials,respectively,and it has a smaller equivalent series resistance,meaning better transport capacity,the reason is that Ni₃(HITP)₂ as a crystalline material has a more regular pore structure,which can more fully utilize the internal space to absorb electrolyte ions,thereby storing more electrical energy.