The Preparation Of The Multidimensional Nano-carbon Which Embedded With Mn₃O₄ Quantum Dots And Its Application In The Electrode Of Elastic Supercapacitor

In recent years,supercapacitor as a new type of energy storage device has a broad application prospect in the fields of new energy and electronic communications due to high energy density,long cycle life and the advantages of the green environmental protection.The electrode material has extremely important influence on the capacity and cyclic stability of supercapacitor.Therefore,the research on the electrode materials of supercapacitor has become one of the focuses by research scholars at home and abroad.Among the many supercapacitor electrode materials,the composited transition metal oxide with nano-carbon materials achieving both advantages is a research hot spot in recent years,which can improve the power density,energy density and cyclic stability of electrode materials with maximum requirement.In this thesis,I used the elastic titanium foil as substrate.With unique templates of sulphur-based gas bubbles in ethanol flame,the hollow carbon nanospheres,embedded with Mn3O4 quantum dots in the margin regions,are quickly synthesized on co-generated nanocarbon supporter on an elastic titanium foil substrate.The fabrication is just carried out by combustion in flame and anneal in air.When used as supercapacitor electrode,the electrode reveals large activity,high cyclic and elastic stability owing to its special structure.After electrochemical testing,the mass specific capacitance of this nanosphere-based electrode is 316 F/g at a scan rate of 2mV/s,which is 94.7%larger than that of the electrode without this nanosphere decoration.Furthermore,the capacitance retention of this nanosphere-based electrode reaches 82.4%after 2000 charge-discharge cycles,and it is 78.3%even if the electrode is continuously vibrated 36000 cycles.These indicate the excellent circulation stability and elastic stability.The sample is treated in the liquid nitrogen environment with the cold quenching process to further optimization of this hollow nanosphere-based electrode which embedded with Mn3O4 quantum dots.These indicate that there are more defects and gaps in the micro-surface morphology,and its cross-section thickness is also increased by some detection technology such as SEM and Raman.After electrochemical testing,we found that the change of the surface morphology of the electrode material can make the hollow nanosphere-based electrode which embedded with Mn3O4 quantum dots after the cold quenching process have higher power density,energy density and higher specific capacity.The specific capacitance reached 397 F/g and increased by 27.7%.The cold quenching process also improves the cycle stability of the prepared electrode.After 2000 cycles,the electrode shows that specific capacitance retention reaches to 86.2%.The above experiments indicate that the flame combustion method is cheap and effective,which has potential in extensive application of synthesizing hollow nanosphere structure materials for electronic device.