Evolution Of Biomass Species (Fresh Yeasts,Hairs) Into Functionalized Carbon Materials For Electrochemical Energy Storage Applications

As a non-renewable resource,fossil fuel reserves have been unable to meet people's growing energy needs.On the other hand,the combustion of fossil fuels causes a lot of harmful gas emissions,which leads to serious environmental problems.Therefore,the development of green,clean,renewable energy and corresponding energy storage equipment has become a key point of current research.Biomass carbon materials have great potential and broad application prospects in electrochemical energy storage due to their wide sources,good renewability and unique natural properties.In this paper,the biomass materials from different sources were processed and modified.The morphology and electrochemical properties of the synthesized materials were characterized and the ir applications in different energy storage devices were studied.The main research contents are as follows:Yeast was used as raw material to immerse the yeast cel s with biological activity in salt solution.The relationship between the treatment time of iron salt solution and the changes of cell microstructure was studied in detail.It was concluded that more iron-containing active substances could be loaded when the immersion reaction time was 60minutes.Then,graphitized carbon microreactor composites containing Fe₃O₄nanoparticles?Fe₃O₄@YE-C?were prepared by high temperature carbonizat io n.Experiments show that the material has good electrochemical properties when it is used as negative electrode material of supercapacitor.Its maximum specific capacities are759.3 F/g and 218.2 mAh/g,and the discharge specific capacities can still be mainta ined at a current density of 1.1 A/g after 2000 cycles of detection.The natural microstruct ures of yeast cel s,on the one hand,can provide channels for ion shuttle,on the other hand,can disperse and confine Fe₃O₄ nanoparticles within each spherical carbon structure to prevent agglomeration during electrochemical reaction.In addition,porous graphitized carbon microtubules were prepared by hydrother ma l treatment and high temperature calcination using hair waste collected as raw materia ls.Specifically,nickel salts are added to the hydrothermal reaction and a basic nickel nitrate layer is formed on the surface of the hair material.In the carbonization process,the basic nickel nitrate layer can catalyze the conversion of amorphous carbon to graphit ized carbon on the one hand,and on the other hand,it can perform"perforation"on the surface of the hair material,thereby increasing its specific surface area,so that the electrodes and electrolytes can ful y contact.The electrochemical reaction rate of the system was guaranteed.The experimental results show that the maximum specific capacity of the material is 689 mAh/g.When the composite material is assembled into a full battery,the specific capacity of the battery can still maintain 72.4 mAh/g at a current density of 1.8A/g.