Preparation And Study On Electrochemical Performance Of Mycelium-doped Carbon Materials By Microbial Enrichment Method

The introduction of heteroatoms into the carbon skeleton can introduce more defect sites in the carbon lattice and enhance the electron transport properties,making it a promising candidate for applications in fuel cells,hydrogen storage,supercapacitors,and biosensors.However,at present,the doping of carbon materials is usually performed using expensive experimental materials,complicated reaction routes,or using toxic chemical reagents.Therefore,it is necessary to find a cheap,simple and environmentally friendly method to achieve the preparation of doped carbon materials from the perspective of practical application.Bioconcentration is a biological phenomenon commonly found in plants and organisms.It can enrich hetero-atom precursors or small-molecule organics inside or outside the cell to provide hetero-atoms.Based on this inspiration,this article provided a method for preparing doped carbon materials that was environment-friendly,low-cost,simple,clean,and controllable macro-preparation and was formed by fungal spore germination under the support of2017GZ0342,a key R&D project of Sichuan Science and Technology Department.Fungal hyphae was used as a biomass carbon source,and carbon-doped materials were prepared by microbial enrichment of atomic precursors.The materials were used for the study of energy storage and conversion.We characterized the structure and electrochemical performance of doped carbon materials and analyzed the relationships between performance influencing factors and structure-activity.The main conclusions are as follows:1.A general strategy for preparing heteroatom doped carbon fiber materials by bioconcentration of fungal mycelium to different toxic organic dyes was developed.The doped carbon fiber has high content of heteroatom and three-dimensional network structure,which showed great potential as the electrode material of supercapacitor.In these products,the N/S co-doped carbon fibers prepared by bioaccumulation MB had the highest specific capacitance of 235 F g^-1 at the current density of 1 A g^-1,and the specific capacitanceretained 72.8%from 1 A g^-1 to 20 A g^-1.This strategy can convert toxic waste into valuable resources,which represents a process that changes damage to treasure.This bioaccumulation method is green,universal and low cost.It is suitable for the preparation of mycelial hetero-atom doped carbon fiber materials using precursor of different hetero-atoms.2.Fe/N co-doped carbon fibers were prepared through bioconcentration of ferrous glycine by fungal hyphae.The mycelium provided a carbon source and a three-dimensional network structure,while the ferrous glycine acted as a Fe/N dopant during carbonization.The three-dimensional network structure facilitated ion transport/diffusion,and Fe/N co-doping provided a rich active site for ORR and capacitance.Fe/N-FHCF-800 showed good redox properties in 1 M KOH aqueous solution.The good capacitance(211 F g^-1)was exhibited in 1 M KOH aqueous solution.When the current density increased from 1 A g^-1 to 20 A g^-1,the capacitance retention rate was as high as 72.21%.After 3000 cycles,the capacitance retention was 87.2%of the original.As a versatile material with both ORR and capacitive properties,it is expected to be applied to the fields of fuel cells and super capacitors.3.Using the in-situ growth and doping method of mycelium combined with the self-assembly characteristics of mycelium,L-cysteine and graphene oxide were added during the growth of mycelium to compound and in-situ growth doping,and N/S was prepared.The impact of carbonization temperature on structure and properties,as well as electrochemical performance under extreme conditions were discussed.Electrochemical results showed that the N/S-GO/FH-800 had high rate performance,good cycle stability and a specific capacitance of 206.0 F g^-1 at a current density of 1.0A g^-1.And the high capacitance can also be maintain under extreme conditions.The good capacitance performance of the N/S-GO/FH-800 electrode material was mainly due to an appropriate amount of doped N/S and the conductivity of graphene.The doping process provided more electrochemically active regions to promote rapid and reversible Faradaic reactions,and the appropriate pore structure and high specific surface area facilitated the transfer of electrolyte ions to the internal materials.