| Sp2 hybrid carbon materials have specific physical and chemical properties such as high conductivity,adjustable interlayer spacing,and stable chemical properties.They play a key role in the storage and conversion of electrochemical energy sources,such as the anode material of SIBs,and as for a catalyst carrier for proton exchange membrane fuel cells（PEMFCs）.Exploring the structure-actity relationship between carbon material synthesis and specific electrochemical properties is the main field of carbon material research.To study the application of carbon material in the field of new energy materials,in this thesis,nitrogen-rich organic compounds are used as precursors,a simple one-step solid phase method and solution reaction method was used to complete self-doping.And then carbonization was used to prepare nitrogen-doped and nitrogen-sulfur co-doped porous carbon materials,of which sodium storage performance was developed.In addition,a model was developed on the basis of the experiment to simulate the catalytic process of Pt catalyst supported on VACNTs in the fuel cell,so as to optimize the parameter during the reaction process and achieve the best catalytic effect.The specific work is as follows:（1）Preparation of nitrogen-rich porous carbon microsphere clusters by solid-phase method and studying its sodium storage properties:The nitrogen-rich organic compound 5-aminouracil was used as a precursor to synthesize porous carbon sphere clusters with high nitrogen content through a one-step solid phase method at different temperatures,and the irregular carbon ball clusters obtained at different carbonization temperatures are applied to the anode of SIBs.The results show that when the carbonization temperature is 750℃,the electrode material exhibits excellent sodium storage performance,and exhibits a reversible specific capacity of 324.5 mAh g-1 at a current density of 50 mA g-1.When the current density increases by a factor of 100,which increases up to 5 A g-1,it still has a reversible capacity of 136.4 mAh g-1.It can be seen that the rate performance is excellent.There is almost no change in the reversible specific capacity after 8000 cycles at the current density of 5 A g-1,showing excellent long-cycle stability.This preparation method that can complete self-doping provides a new idea for the synthesis of nitrogen-doped carbon materials.（2）Preparation of nitrogen-sulfur co-doped dendritic porous carbon and studying its sodium storage properties:Taking a nitrogen-rich organic matter named 2,4-diamino-6-methyl-1,3,5-triazine as the carbon source,ammonium persulfate serves as both an initiator and a small amount of sulfur source,these reactants self-polymerized under ice-water bath conditions.The product was dried drying and carbonized at 900℃ to obtain a nitrogen-sulfur co-doped porous carbon material.Thiourea was added to the reaction system to increase the sulfur content of the porous carbon,and explor the sodium storage performance influenced by the sulfur content of the electrode material.The porous carbon prepared in the system without adding thiourea showed a reversible specific capacity of 202.4 mAh g-1 and the initial coulombic efficiency of 40.8% at a current density of 50 mA g-1 when applied to the anode material of SIBs.With thiourea added,the reversible specific capacity increased to 268.7 mAh g-1,and the initial coulomb efficiency increased to 50.2%.（3）Fabrication of vertically aligned carbon nanotubes（VACNTs）,performance test and simulation of cathode catalyst layer（CCL）:Using ethylene as carbon source,VACNTs were prepared by plasma enhanced chemical vapor deposition method and applied to CCL of fuel cell,A 3D model of an order-structured cathode catalyst layer under water flooding condition was developed based on the experiment,which used vertically aligned carbon nanotubes as the catalyst support.It was used to optimize the structure of VACNTs CCL and explore the possibility to achieve the DOE 2020 target.The model effectiveness is validated by comparing to a single practical fuel cell.Meanwhile,parametric studies including the length and the spacing of VACNTs and the Nafion thickness was carried out to optimize the order-structured CCL.The results demonstrate that the VACNTs CCL has excellent performance even under water flooding condition due to its fast reaction characteristics and by optimization of electrode structure,the current density of optimized CCL can be increased by 26% at cathode potential of 0.8 V and the current density can be increased by 84%at 0.75 V,compared to that of the practical VACNTs CCL.Furthermore,the DOE 2020 targets can be fulfilled with feasible CCL parameters adjustment including the radius of VACNTs,the catalyst surface area per unit mass,the flooding conditions and the Pt loading,which make the order-structured electrode a very promising candidate to enhance the development of PEMFCs with ultra-low Pt loading. |
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