Resource Treatment Of Waste Biomass And Its Application In Energy Storage

In recent years,waste biomass resources are common waste resources in life.As a renewable resource in nature,it has the advantages of wide source and green environmental protection,and has shown great application potential in the fields of electrochemical energy storage and environmental pollution remediation.However,the traditional way of resource utilization of waste biomass is easy to produce secondary pollution and complex operation,and even involves food safety,and it is urgent to find new ways of resource utilization.The use of waste biomass,compared with the field of environmental pollution remediation,the field of electrochemical energy storage has greater room for exploration,and the promotion of waste biomass to green and environmentally friendly biomass material resource utilization,so that it turns waste into treasure and reduces environmental pressure,is in line with the current needs of environmental protection,energy conservation and environmental protection.In this paper,two kinds of waste biomass,water hyacinth and kapok fiber,were used as carbon precursors to prepare porous carbon and modified composites with different microstructure and surface chemical properties,and their application in the field of clean energy was explored.It provides a basis for the development of high-performance and environmentally friendly energy storage electrode materials and high-value utilization of waste biomass resources.The main research contents and conclusions of this paper are as follows:（1）By acid treatment and chemical activation,water hyacinth and kapok fibers were poreized,and lithium-ion half-cells were assembled with them as active substances.Through a series of characterization and tests such as SEM,XPS,etc.Nitrogen-doped water hyacinth-derived porous carbon（NWPC）was prepared by adjusting the pores of pyrolyzed water hyacinth with different concentrations of HCl,and the results showed that the lithium intercalation reaction kinetics of NWPC-2 were the best at a concentration of 2 mol/L HCl.Therefore,this NWPC-2 electrode can maintain a reversible specific capacity of 428 m Ah/g after 120 cycles at a current density of 0.2 A/g,and its rate performance is also superior to that of NWPC-1 and NWPC-3.The specific capacity of KPC-800°C in the first 160 cycles remained at 463 m Ah/g,compared with KPC-700°C（399 m Ah/g）and KPC-900°C（279m Ah/g）,indicating that KPC-800°C cycle performance was better,and its rate performance was better than KPC-700°C and KPC-900°C.（2）Using nitrogen-doped water hyacinth derived porous carbon（NWPC）as the carbon skeleton,the NWPC/Fe OOH composite material was constructed by hydrothermal method,which can improve the specific capacity of carbon-based NWPC,and NWPC alleviates the volume effect of Fe OOH and improves the conductivity of the composite.Through electrochemical lithium storage research,the specific capacity of NWPC/Fe OOH can be maintained at 530 m Ah/g for 135 cycles at 0.2 A/g,and the reversible capacity of 721.9 m Ah/g（700 cycles of cycles）can be maintained at 1 A/g.Due to the synergistic effect of Fe OOH high specific capacity,naturally doped N atoms and porous structure,NWPC/Fe OOH composite electrode exhibits better cycle performance and rate performance.（3）KPC/α-Fe₂O₃ was prepared using kapok fiber-derived porous carbon as the carbon framework and Fe Cl₃·6H₂O as the iron source,and the polypyrrole-coated KPC/α-Fe₂O₃@PPy composite was further synthesized by solution method.At a high current density of 1 A/g,the specific capacity of KPC/α-Fe₂O₃@PPy composites is 942 m Ah/g after 500cycles as the anode of the lithium-ion battery.The excellent electrochemical Li⁺ion storage capacity of the material is due to the high theoretical capacity ofα-Fe₂O₃ and PPy conductive polymer,while KPC porous carbon alleviates the volume change ofα-Fe₂O₃ in the cycle,creating more active sites for lithium storage,which is conducive to the diffusion of lithium ions and the transport of electrolyte,thereby improving the electrochemical performance.KPC/α-Fe₂O₃@PPy composites ultimately exhibit faster lithium-ion kinetics,excellent rate performance and excellent cycling properties.