The Research Of N,P Co-Doped Porous Carbon Prepared By Direct Carbonization As High-Performance Anode For Lithium-Ion Battery

Lithium ion battery as an important energy storage equipment has been widely used in various fields.The key factor that determines the performance of lithium-ion battery lies in the anode and cathode materials.The positive electrode materials mainly include LFP and Li Co O₂,and the negative electrode materials mainly include silicon-based materials and carbon-based materials.Silicon-based anode material has low conductivity,easy to fall off from the collector during charging,and poor cycle stability.The above shortcomings can not be completely solved in a short time.Among the carbon-based anode materials,graphite is the representative.However,its theoretical capacity is low,and it is easy to grow lithium dendrites.Porous carbon,as a cathode material,has attracted more and more attention in recent years.In order to achieve a higher degree of graphitization in the precursor carbonization process,a higher temperature is often required,and additives such as activators may be added for different precursors,which will have a certain impact on the environment and increase the production cost.It is therefore extremely necessary to develop low-cost and environmentally friendly materials.Hierarchically porous carbon derived from pig bone has been synthesized to meet the increasing demand of carbon-based anode electrode material for lithium-ion batteries（LIBs）.Pig bone with unique structure and high content of inorganic minerals（Ca₃（PO₄）₂,Ca CO₃）acting as self-template was selected as precursor for the preparation of porous carbon and no more additive agents were needed.When tested as anode material for lithium-ion batteries（LIBs）,the as-obtained porous carbon exhibited excellent initial reversible capacity(1308 m Ah g^-1 at 0.1 A g^-1),superior cycling performance(640 m Ah g^-1 at 0.5 A g^-1 after 500 cycles),and desired rate capability(304 m Ah g^-1 at 5 A g^-1).The outstanding electrochemical properties can be ascribed to the abundant existence of micropores,the specific microstructure,and doped with N and P elements.Porous carbon derived from obsolete eggshell was fabricated by one-step calcination strategy and applicated in lithium ion batteries（LIBs）.Eggshell acted as template to create nanopores,the residual egg white used as natural carbon source.When the carbon material was used as anode in LIBs,superior rate(1 A g^-1 for 823 m Ah g^-1,5 A g^-1 for 587 m Ah g^-1,20 A g^-1for 302 m Ah g^-1)and reversible capability(1225 m Ah g^-1 at 0.1 A g^-1)was obtained.The remarkable performance was ascribed to the distinctive hierarchical microstructure,high content（>10%）of N doping and a large amount of micropores.