Study On The Preparation And Application Of Two-Dimensional Layered Black Arsenic Phosphorus

The two-dimensional materials are combined by covalent bonds or ionic bonds,and the layers are linked by weak van der Waals forces.Twodimensional materials can be easily stripped into thin layers or single layers.In 2004,the graphene is stripped from the bulk graphite.Because of its unique two-dimensional structure and outstanding physical properties,it has attracted extensive attention and opened up a research upsurge in two-dimensional crystal materials.Graphene like materials are similar to graphene in structure,but have different physical and chemical properties from graphene,such as hexagonal boron nitride(h-BN),and transition metal sulfides,gallium nitride,silicene,germanene,black phosphorus and black arsenic phosphorus.Graphene like materials with different atomic composition have different structures and properties,so they can play their respective advantages in different application fields.At the same time,it also has some shortcomings.Boron nitride is generally used as an insulating medium or substrate in electronic devices because of its large band gap.The properties of transition metal sulfides are very layer dependent,and the band gap will change with the number of layers.but the obvious disadvantage is the low carrier mobility.Germanene has no band gap and strong covalent bonds between atoms,which hinders its practical application.Therefore,some assembly techniques enable graphene-like materials to complement each other and give full play to their own advantages.Novel properties often emerge as the dimensionality of materials is reduced.The recently discovered black phosphorus and black arsenic phosphorus have excellent properties such as band gap can be controlled by the number of layers,high carrier mobility,anisotropic properties and higher theoretical capacity than graphite,which make them have potential applications in many fields such as field effect transistors,sensors,photocatalysts and energy storage(battery)applications.In this thesis,we mainly study the controllable preparation,morphology and other basic properties and application performance of two-dimensional layered black phosphorus and black arsenic phosphorus.The main contents of this thesis are as follows:(1)Black phosphorus was prepared by atmospheric pressure mineralizerassisted method,in which analyzed pure red phosphorus was raw material,which reduced the preparation cost.The crystal structure and morphologies of black phosphorus were analyzed by x-ray diffraction,Raman spectroscopy,xray photoelectron spectroscopy,scanning electron microscopy and transmission electron microscopy.The results show that the crystals are orthogonal black phosphorus.The black phosphorus crystals grow diversely like "petals" with good crystallinity,lamellar structure and black metallic luster.Black phosphorus was applied to the anode material of lithium-ion battery.The first capacity was up to 2345 mAh g-1,After 50 cycles,the capacity decreases seriously,only to 275 mAh g-1.Meanwhile,the discharge platform is also greatly shortened.The main reason is that in the process of charge and discharge,the deformation or shedding of the material structure is caused by the volume expansion of the electrode material,which leads to the reduction of the cyclic stability.This job comes to be the basis for building stable composite structures to obtain Phosphorus-based LIBs anode materials with better performance.(2)The two-dimensional structure of black arsenic phosphorus plays a key role in a wide range of applications due to its unique physical properties and flexible structure.On the basis of black phosphorus,B-AsP materials were synthesized via the sponsor-assisted gas phase transport.The raw Materials were a mixture of gray arsenic and red phosphorus,and a mixture of SnI4 and Sn was used as a mineralizer.The gray arsenic and red phosphorus with molar ratios of 0:1,1:3,3:1,and 83:17.We described the synthesis and characterization of the two-dimensional black arsenic phosphorus materials with different components in detail by XRD,Raman,XPS,SEM and TEM.And the electrochemical properties of black arsenic phosphorus with different components as anode materials for lithium-ion batteries were studied.The results show that the black arsenic phosphorus compound materials have a good crystallinity and composition close to the designed value.Meanwhile,we applied them to the anode materials of LIBs.The test results showed that,at different current densities,B-As0.25P0.75 had a better specific capacity than BAs0.75P0.25 and B-As0.83P0.17.Different components of black arsenophosphorus show higher specific capacity than graphite in the first charge-discharge cycle,reaching 1341 mAh g-1.It provides basic support for the research on the energy storage performance of black arsenic-phosphorus materials.(3)The black arsenic-phosphorus/carbon nanotubes composites were successfully prepared by mechanical stripping and ball milling.The application of black arsenic phosphorus/carbon nanotubes composites in the field of lithium-ion batteries was studied.Carbon nanotubes provide a reasonable support for black arsenophosphorus with carbon nanotubes playing a role of conductive channels and elastic buffers.And it reduces the problem of shedding of active substances caused by volume expansion of black arsenophosphorus during the lithium process.The results show that Carbon nanotubes were well distributed in black arsenic and phosphorus.As an electrode material for lithium-ion batteries,the black arsenophosphorus/carbon nanotube composite has better capacity(1825 mAh g-1),conductivity(57.5 Ω)and good rate performance(322 mAh g-1 at 1000 mA g-1)than single-phase black arsenophosphorus.In the black Arsenic-phosphorus/carbon nanotube composite,carbon nanotubes are closely combined with the laminates of black arsenic phosphorus to form a stable chemical bond,forming channels for the transfer of lithium ions and ensuring the good electrical conductivity of black arsenic phosphorus/carbon nanotubes.In the black arsenic phosphorus/carbon nanotubes composites,the especially layered structure of black arsenic phosphorus could provide enough space for ion intercalation/deintercalation,and could further improve the electrochemical performance of the composites.(4)In black arsenic phosphorus/carbon nanotube composite materials,on the basis of using the method of ball mill preparation of graphene oxide/black arsenic phosphorus-carbon nanotube composite materials.In the lithium-ion battery test,the charging and discharging capacity of the composite electrode is 1173 mAh g-1 and 746 mAh g-1.In the subsequent 50 cycles,the reversible capacity reaches 86%,and there is still 693 mAh g-1 reversible capacity,maintaining a relatively stable state.The electrode capacity of GO/B-AsP/CNTs composites is 1286 mAh g-1 at 0.1 A g-1,and the reversible capacity of the electrode of GO/B-AsP/CNTs composites can be recovered to 339 mAh g-1 after cycling with different current densities.Due to GO better characteristics and abundant functional groups,in the process of ball mill,black between arsenic phosphorus compound material and the GO to form stable P-C,As-C,stable black arsenic phosphorus structure further.(5)The preparation and photoelectric properties of black arsenic phosphorus crystals with different thickness were studied.Black arsenic phosphorus field effect transistor with different thickness was fabricated by mechanical stripping and the dry transfer method.Then the transfer and output characteristic curves of the device have been tested and analyzed.It is found that the black arsenic phosphorus thin films field effect transistor prepared in this work shows typical p-type field effect characteristics,and various electrical properties are excellent.These results further provide insights and cognition into important of black arsenic phosphorus and show great potential for future in many aspects.