Research On Supercapacitors Based On Biomass Carbon Functional Materials

Energy issue is a theme that the whole world is concerned about.The globalization and modernization of the economy and the development of the world are inseparable from the extensive application of fossil energy,such as oil,natural gas and coal.The problem of global energy crisis will become increasingly prominent due to The world's pursuit of industrialization speed which led to the accelerated consumption of energy.In addition,the use of fossil fuels has also led to serious environmental problems.The energy crisis and environmental problems pose a direct threat to the survival and development of mankind.Therefore,developing sustainable clean energy and researching advanced energy storage technology has become a very urgent problem.The emergence of supercapacitors provides a possibility for sustainable development.Supercapacitors can not only provide energy density of several orders of magnitude larger than traditional capacitors.Moreover,it has higher power density and better cycle performance than traditional batteries.Some components of supercapacitors,such as electrode,basal material and electrolyte,play an important role in the performance of supercapacitors.In recent years,biomass as carbon source is a research hotspot in the field of electrode materials.At the same time,in order to make flexible supercapacitors,the choice of outer packaging materials has been studied by more and more researchers.In this paper,supercapacitors are taken as the research object.By studying the components of supercapacitors,we use biomass materials as electrode materials and outer packaging for supercapacitors,then measured the electrochemical performance and compared with The supercapacitors made from non biomass materials.1.Bamboo fiber was used as raw material and a series of operations are activated by high temperature carbonization to get bamboo charcoal Fiber.Bamboo charcoal fiber and Potassium Permanganate to get together by in-situ hydrothermal synthesis reaction.The electrochemical properties of pure bamboo charcoal fiber electrode material and MnO2/bamboo charcoal fiber composite electrode material were studied.It was found that pure bamboo charcoal fiber has good electrical conductivity.After the 5000 cycle,the capacitance is 97.6%to the origin.After compounding bamboo charcoal fiber and MnO2,the specific capacitance of composite electrode material is improved.When the MnO2 ratio is 24%,the specific capacitance of the composite electrode material is 152 F g-1.The capacitance is far greater than that of pure bamboo carbon fiber electrode material.However,the MnO2 in the composite electrode material improves the specific capacitance while reducing the conductivity of the electrode material.When the MnO2 ratio is 39%,the electrical conductivity of the composites is seriously decreased.The specific capacitance is only 58.5 F g-1.Therefore,when bamboo charcoal fiber is combined with MnO2,a suitable proportion should be selected,considering both electrical conductivity and specific capacitance.2.MnO2 was grown on graphene to form composite electrode materials by in-situ hydrothermal synthesis.When the graphene was not added,the average diameter of MnO2 synthesized by hydrothermal synthesis was 95 nm,and the aspect ratio was 12.9.The specific capacitance of the material at this time is 63.75 F.g-1;When the proportion of graphene in composites is 20.4%,the average diameter of MnO2 in composite is 86 nm,and the aspect ratio is 28.The specific capacitance of the material at this time is 116.6 F.g-1;When the proportion of graphene in composites is 34%,the average diameter of MnO2 in composite is 70 nm,and the aspect ratio is 52.4.The specific capacitance of the material at this time is 187 F.g-1 The addition of graphene increased the conductivity and increased the ion binding site.The supercapacitor based on this material has higher capacitance,more stable cycle performance and better conductivity.3.Use spin cutting method,we turn Fraxinus mandshurica into thin slices,as the basal material of flexible supercapacitor,it will replace the traditional outer packaging material PET.The two kinds of materials were used to make two sets of capacitors.The electrochemical performance of the supercapacitors was measured after bending 45 and 90 degrees and 100 times after bending,respectively.When the flexible supercapacitor manufactured by PET are bent at 45,90 and 100 times,the capacitor performance is 98.5%,94.3%,92%,respectively;Compared with the capacitance without bending,the capacitive performance of the capacitor manufactured by Fraxinus mandshurica slice is 98%,96%and 95.5%when the capacity of the capacitor are bent at 45,90 and 100 times.The results showed that the Fraxinus mandshurica slice had the same bending performance as PET.Because the Fraxinus mandshurica is a biomass material and more environmentally friendly,so it is a more ideal material for outer packaging of flexible supercapacitors.