The Preparation Of Advance Porous Carbon Materials And Their Application In Anode Of Lithium-Ion/Sodium-Ion Batteries

As energy and environmental issues become more serious,such as pollution,depletion of fossil fuels and global warming,the demand for clean and renewable energy materials is urgent.Graphite is the most commonly commercial material for lithium ion battery anodes because of its low cost and low electrochemical potential.Graphite dominates the battery market and is widely used in portable electronic products such as notebook computers,digital cameras,and mobile phones.At the same time,the limited lithium resources,the rapid development of various electronic and electric vehicles have led to an increasing demand for lithium ion batteries.Therefore,sodium ion batteries are considered to be promising replacements for lithium ion batteries due to their abundant sodium resources and similar electrochemical properties.It is worth noting that the feasibility of sodium storage for carbon materials with abundant resources,low cost,non-toxicity and high safety has been confirmed,and a large number of studies have shown that carbon materials can be an ideal choice for anode of sodium ion batteries.In this paper,porous carbon materials with porous shape and large specific surface area were prepared by designing the synthesis method of carbon materials and optimizing experimental conditions.In the third chapter,a new method for preparing porous carbon is described in detail.It was proposed that using a simple magnesia reduction reaction and melamine as a carbon and nitrogen source to prepare a porous carbon with a large specific surface area.The obtained porous carbon was tested as anode of a lithium ion battery,which exhibited a very excellent and stable electrochemical performance.At a current density of 0.1A g-1,it exhibited stably specific capacity 1250 m Ah g-1 after 100 cycles,which is higher than the theoretical specific capacity of graphite of 372 m Ah g-1.It provides a new choice for the preparation of porous carbon materials by using a simple magnesium thermal reaction to prepare a porous carbon material with excellent electrochemical propertiesIn the fourth chapter of this thesis,we used dopamine as nitrogen-containing carbon precursor and KOH as activated agent.The porous carbon material possesses a specific surface area as high as 3200 m2g-1.The obtained porous carbon was tested as anode of lithium ion battery,and showed a stable specific capacity of 1180.9 m Ah g-1at a current density of 0.1A g-1.The electrochemical performance was excellent,which was far greater than the theoretical specific capacity of graphite 372 m Ah g-1.Such a high specific capacity performance of carbon materials is worthy of attention.In the fifth chapter of this thesis,we demonstrated a porous carbon with ultrahigh specific surface area using biomass material longan shell as a carbon source and the KOH as activated agent.The specific surface area can reach 2988 m2g-1 by testing with a specific surface tester.The obtained porous carbon was tested as anode of sodium ion battery,which remained 350 m Ah g-1at a current density of 0.1 A g-1,and even at a current density of 5 A g-1,it still remained a high specific capacity 300 m Ah g-1.At 5 A g-1 current density,the porous carbon materials with high specific capacityis relatively rare in previous reports.