Constructi On Of High-performance Sodium Ion Energy Storage Devices Based On Vanadium-based Metal Organic Framework Derived Materials

Lithium-ion batteries are currently the mainstay of portable energy storage devices.However,the limited lithium resources and uneven distribution in geographic conditions hinder the sustainable development of lithium-ion energy storage technology.Sodium has similar physicochemical properties to lithium.With abundant resources and low cost,sodium ion energy storage technology is considered to be a new generation of energy storage system with great development potential.Among them,sodium ion hybrid capacitors（SIHCs）have been developing rapidly in recent years because of both the high energy density of secondary batteries and the high power density of supercapacitors.However,the mismatch in energy storage kinetic behavior due to the different energy storage mechanisms of positive and negative electrodes is the main problem encountered in the development of sodium ion hybrid capacitors.Therefore,finding battery-type electrode materials with fast ion transport kinetic characteristics and stable structure is the key to solve the above problems.In this thesis,based on their large specific surface area,high porosity and tunable morphology,vanadium-based metal-organic framework materials（MOFs）are used as precursors to prepare metal oxide/carbon nanocomposite anode materials,vanadium-based selenium oxide/carbon composite anode materials and MOFs-derived metal oxide cathode materials with fast kinetic behavior through high-temperature pyrolysis reactions to study their energy storage performance and construct a series of high-performance sodium ion energy storage devices.The main research contents are as follows:（1）MIL-88B（Ⅴ）was used as a precursor to prepare polymer retaliation products MIL-88B（Ⅴ）@PZS by a simple chemical polymerization method,and a series of pencil-like hollow rod-like c-V₂O₃@CNPS materials were prepared by high-temperature pyrolysis.The effects of pyrolysis temperature on product morphology,specific surface area,pore structure,heteroatom content,etc.were systematically investigated to explore the differences in sodium ion energy storage behavior of different products,to screen the negative electrode materials with high sodium ion energy storage specific capacity and fast ion transport kinetic behavior,and construct sodium high-performance sodium ion hybrid capacitors,(energy density up to 124.6 W h kg^-1 at 420 W kg^-1 power density).（2）Using MIL-88B（Ⅴ）@PZS as the precursor and selenium powder as the selenium source,pencil-like porous VSe₂/V₂O₃@CNPS composite anode materials were prepared by high-temperature gas-solid phase reaction to systematically study the material sodium ion energy storage performance.Biomass-derived porous carbon was used as the positive electrode to construct a high-performance sodium-ion hybrid capacitor.The device can provide an energy density of 119.11 W h kg^-1 at a power output of 420 W kg^-1.（3）The pencil-shaped nanoporous V₂O₅/C cathode material was prepared by adjusting the pyrolysis temperature in air atmosphere using MIL-88B（Ⅴ）as the precursor,and the sodium ion energy storage characteristics of the material were investigated.Finally,c-V₂O₃@CNPS-650 and VSe₂/V₂O₃@CNPS were used as negative materials and V₂O₅/C as positive materials,respectively,and the sodium ion full batteries were successfully assembled by mass matching optimization of positive and negative electrodes to demonstrate the practical application potential of such materials.