Preparation And Electrochemical Properties Of CN Nanomaterials

Because of the special nanostructures and good conductive performance,the carbon nanomaterials is widely applied in the lithium ion battery and super capacitor.But the lithium ion battery of carbon nanotubes for anode is not perfect,the specific capacity of lithium ion batteries is only around 200 m Ah/g.The specific capacity will be on the decress with the increase of cycling number,which is a terrible question.In order to solve this question,marry people dedicated to product the nitrogen doped carbon nanotubes.The CNX is more stable and safer than carbon materials.And the CNX will decompose until temperature up to 550?.Our previous study found it is possible that we can prepare CN nanotubes under milder conditions.The nitrogen content is almost no loss in the production process.It is about one gram of material quality.The preparation of high nitrogen content of CN nanotubes used in lithium-ion battery anode materials and super capacitors,which may have more excellent performance than carbon nanotubes.In this thesis,we explore the growth mechanism of CN nanomaterials and prepare a sheet of graphite-phase CN.The graphite-phase CN can dispersion in water very well and it can be peeled by ultrasonic.CN has low-rise structure.This provides a new way for producting CN material that has high nitrogen content type graphene.CN material as lithium ion battery anode was found the specific capacity was increased with circulates.The initial specific capacity of CN is very low.In order to improve the initial specific capacity,we will product the CN naotubes.The SEM images show that the minimum diameter is about 20 nm,and the maximal diameter is up to 500 nm.The nanotubes have open ports.XRD images show that CN nanotubes are like graphite-phase structure.The CN nanotubes whichdiameter is20-150 nm as anode material for lithium-ion batteries,we found that the highest initial specific capacity of the CN nanotube can reach 220 m Ah / g.The specific capacity will increase with the increase of test times When it is 100 th cycle,its capacity can reach more than 320 m Ah / g.In the case of high-current(1A / g)charging and discharging,CN nanotubes capacity of lithium-ion battery is still on the rise.This phenomenon is a good solution for the materials which the specific capacity decrease.XPS results show that with the progress of the cycle,CN nanotubes graphitized N gradually transformed into pyridine N and pyrrole N.Pyridine N and pyrrole N will enhance the CN nanotubes' electronegativity,CN nanotubes improve the ability to bind lithium ion.In the course of a cycle,CN nanotubes bound to increase lithium ion,CN nanotubes of the lithium-ion battery's specific capacity increases.We also test CN nanotubes' supercapacitor materials with current is 1.5A/g.After 1000 cycles,CN nanotubes' specific capacitance is 155.3F / g,indicating that the nanotubes as CN super capacitor has excellent properties.