The Preparation Of Porous Nanocomposites And Their Application In The New Energy Storage Equipment

Since the 21 st century,the development of portable electronic devices and the popularization of new energy electric vehicles have promoted the development of relevant industrial chains?new energy batteries?.One of the core equipment of the new energy vehicle is the new Li ion batteries.From the developmental direction of new energy batteries,new energy batteries can be divided into lithium-ion batteries,fuel cells and supercapacitors.Lithium ion batteries gradually become a new clean energy devices applied in automobiles and portal electronic equipment.As we all know,the current commericial anode materials for lithium ion battery are graphite.And supercapacitor is also a kind of electrochemical capacitors,it is a new type of energy storage devices which is between the traditional capacitor and rechargeable batteries,its capacity of are much higher than conventional capacitors.At present,it has caused wide attention through the preparation of nanocomposites with renewable ability as a new anode material for Li ion batteries to solve the growing energy crisis and environmental problems.This paper is mainly about the preparation of several classes with porous nanostructures based composite material of the preparation of metal oxide composite material and applied to the new energy storage equipment.The releated research content mainly includes the following four works:1.The as-prepared ZnO/ZnFe₂O₄ @ C nanocomposite was obtained by calcining synthetic mixed metal organic framework Zn/Fe-MOF.we found that the ZnO/ZnFe₂O₄ @ C nanomaterial have 3D ball-in-ball structure with hollow core-shell structure,and ultrafine ZnO and ZnFe₂O₄ evenly coated on the surface of amorphous carbon layer which can be obtained through the organic ligands in situ carbide structure.Nitrogen adsorption/desorption results of Zn O/ZnFe₂O₄ @ C composites showed that the surface area of Zn O/ZnFe₂O₄ @ C can reach to 126 m2/g.High specific surface area is beneficial to the rate performance of ZnO/ZnFe₂O₄ @ C.After 100 cycles,the ZnO/ZnFe₂O₄ @ C electrode can release the capacity of 1283 mAh/g mA and 1100 mAh/g at the current density of 100 mA/g and 200 mA/g,respectively,which is much better than the theotetical capacity of pure graphite.2.The NiCoZn layered double hydroxide?NiCoZn-LDH?was obtained by etching Zn/Co-ZIF using nickel nitrate.The Zn/Co-ZIF severed as sacrificial-template and presusors.We get multi-component metal oxide composite of 3NiO·2Ni_3/2Co_1/2ZnO₄ by calcining NiCoZn-LDH in air.The nanocomposite material has hollow structure with dodecahedron by transmission electron microscopy?TEM?observation.Hollow structure is beneficial to the diffusion of lithium ions and electrons during the process of charge/discharge.When severed as anode material for lithium ion batteries,the 3NiO·2Ni_3/2Co_1/2ZnO₄ can release the capacity of 1337 mAh/g at the current density of 200 mA/g after 100 cycles.The multi-component mixed metal oxide nanocomposites not only when used in lithium ion battery performance excellent potential application value,and for the preparation of composite material provides a variety of ways.3.The melamine foam which is cheap contains abundent nitrogen element and carbon element and it has 3D macroporous structure and superlight quality.The 3D structure can get more activite sites after the carbonization process.We can get Co3O₄/Carbon foam?Co3O₄/CF?by using foam carbon as support material and grow Co3O₄ nanoparticles on the surface of 3D macroporous structure.The Co3O₄ nanoparticles can evenly grow on the surface of melamine foam carbon after carbonization process.When it severed as anode material for lithium ion batteries,the Co3O₄/CF electrode still is able to release the capacity of 1287 mAh/g under the current density of 200 mA/g after 100 cycles.This approach is flexible and inexpensive.4.Polyaniline?PANI?combined with zeolite imidazolate framework-67?ZIF-67?@carbon nanotubes?CNTs?/carbon cloth?CC?was constructed as electrode material for supercapacitors.Originating from the synergistic effect of PANI?including excellent electrical activity,well pseudo capacitance,good chemical doping/undoping?and CC/ZIF-67,and the obtained PANI-CNTs@ZIF-67-CC nanocomposites showed high specific capacitance when used for electrodes to fabricate supercapacitors.Under the sweep rate of 10 mV s-1,PANI-CNTs@ZIF-67-CC nanocomposites exhibited a specific capacitance of 3511 mF cm^-2.Furthermore,with the current density of 0.5 mA cm^-2,the specific capacitance maintained 83% after 1000 charging/discharging cycles.