Preparation And Performance Characterization Of Porous Carbon Materials Based On Biomass And MOFs

With the economic and social development,energy and environmental issues are increasingly becoming a major challenge for us.Therefore,the search for or development of new energy storage materials has attracted the attention of researchers.Porous carbon materials play an increasingly important role in the field of energy storage and conversion because of their inherent advantages such as high electrical conductivity,stability,and complex pore structure.In my works,biomass or MOFs are mainly used as precursors to synthesize porous carbon materials.We characterize the morphology and structure of the material and study the performance of the material.Functional porous carbon materials with high specific surface area,complex pore structure and specific substance doping were obtained by different preparation schemes using cheap biomass or easily synthesized MOFs as precursors.And we have also studied their applications in lithium-ion batteries,lithium-sulfur batteries,and electrocatalytic hydrogen evolution.1、We use a simple template method to polymerize pyrrole to form nanotubes（Ppy tube）.Then we synthesize MoS₂ nanothorns epitaxially grown on Ppy tube by hydrothermal method.The material is annealed to improve the crystallinity of MoS₂,and the Ppy tube is also derivatized into a nitrogen-doped nanotube.Finally,the conductive polymer poly（3,4-ethylenedioxythiophene）（PEDOT）is coated to improve the material’s strength and conductivity.We use a range of instruments to characterize the topography and composition of materials（eg XRD,SEM,TEM,etc.）.MoS₂ grown on the PPy tube disperses more uniformly and provides higher conductivity than the agglomerated MoS₂,thereby reducing the volume change during the cycle,increasing the safety of the battery,providing more stable active sites and promoting the kinetics of the electrode reaction.The PEDOT-coated electrode provides greater contact and faster electron transfer speed.Due to the synergistic effect,the obtained composite material exhibits excellent lithium storage properties:high specific capacity(about 1200 mAhg^-1 at 100 mAg^-1),excellent cycle stability(823mAhg^-1 at 500 mAg^-1 for 100 cycles)and good rate performance.These all illustrate their potential applications in commercial lithium batteries.2、The transition metal doped nitrogen-containing porous carbon materials are synthesized by hydrothermal carbonization（HTC）and gas activation（CO₂）using melon and MOF（PBA）as precursors.We use a range of instruments to characterize the topography and composition of materials（eg XRD,SEM,TEM,etc.）Porous carbon material exhibits good electrochemical performance when the sulfur loading is 64wt%:high specific capacity(about 1100 mAhg^-1 at 0.1 C),excellent cycle stability(500mAhg^-1at 1 C for 100 cycles).The increased capacity is attributed to the chemical confinement of transition metal and nitrogen doping to polysulfides and the physical limitation of porous carbon materials to polysulfides.3、The precursor is prepared by PZS-coated MOF（Prussian Blue）.During the carbonization process,PBA is used as the Co/Fe/Ni source,and PZS is used as the phosphorus source.The prepared porous carbon material has a large specific surface area.The effects of doping amount of precursors of different MOFs on electrochemical performance in the later stage are investigated.Finally,it is found that CoPBA-PZS-C-100and NiPBA-PZS-C-100 have the best electrochemical performance.