Research On Modification And Application Of Wood-based Micro-nano Carbon Sphere

Wood-based micro-nanospheres were prepared by emulsion method from wood phenol liquefaction in this paper.Wood-based hollow carbon spheres（WHCS）were obtained by semi-curing,dissolution,secondary curing,carbonization and activation.Then cobalt/nickel coated WHCS（Co Ni LDHs/WHCS）composites and nickel/sulfur coated WHCS（Ni S/WHCS）composites were prepared by ethanol thermal deposition method.The microscopic surface,specific surface area and pore size distribution,crystal structure,surface functional groups,oxidation state of metal elements and graphitization degree of WHCS,Co Ni LDHs/WHCS,Ni S/WHCS were studied by SEM,specific surface area and porosity analyzer,XRD,XPS and Raman spectroscopy,and their electrochemical properties were studied in detail,which provided an important scientific basis for the development of smart packaging components.The main conclusions are as follows:1.Through the study of WHCS obtained at different semi-curing times,it is clear that WHCS-10 has a specific surface area as high as 1610 m²/g and a hierarchical porous structure when semi-curing for 10min.At the same time,it has complete sphericity and maximum cavity volume.Electrochemical test results show that the specific capacitance of WHCS-10 is as high as 139.8 F/g at 0.5 A/g,and the capacitance retention rate is as high as77%after 3000 cycles of charge and discharge.2.Co Ni LDHs/WHCS were prepared by coating different proportions of cobalt/nickel on the surface of WHCS by ethanol thermal deposition.SEM results show that the surface of WHCS is a layer of flower-like nanosheets,and the coated nanosheets will block the pores on the surface of WHCS,resulting in a sharp decrease in the specific surface area and pore volume of Co Ni LDHs/WHCS.Electrochemical test results show that the specific capacitance of Co₃Ni₂LDHs/WHCS is as high as 924.4 F/g at 1 A/g,and it is still 734.0 F/g at 10 A/g,and the capacitance retention rate is as high as 79.6%.After 500 cycles of charge and discharge,the cycle life of Co₃Ni₂LDHs/WHCS is 67.6%.Compared with Co Ni LDHs,the cycle life of Co₃Ni₂LDHs/WHCS is increased by 45.7%,which indicates that Co₃Ni₂LDHs/WHCS has high cycle stability and excellent specific capacitance.3.Ni S/WHCS was prepared by coating different contents of nickel and sulfur on the surface of WHCS by ethanol thermal deposition.SEM results show that it has a core-shell structure,and with the increase of nickel content,WHCS is gradually completely coated,which leads to a large reduction in the specific surface area and pore volume of Ni S/WHCS.Electrochemical test results show that the specific capacitance of Ni₄S/WHCS is as high as991.0 F/g at 1 A/g,and it is still 448.3 F/g at 10 A/g,and the capacitance retention rate is45.2%.After 1000 cycles of charge and discharge,the cycle life is 72.8%.Compared with Ni S,the cycle life of Ni₄S/WHCS is increased by 82.5%.