Design And Preparation Of Metal Oxides And Their Composites As Anode Materials For Lithium Ion Batteries

With the depletion of non-renewable energy sources such as fossils and the rise of new energy vehicles,commercial lithium-ion batteries have been widely used in various aspects of daily life.Even so,the research of high-performance lithium-ion battery materials with higher energy density and longer service life is still a hot topic in the field of energy.In this paper,CuO@C nanocomposites,MnO@C nanocomposites and MnO@NC nanocomposites were prepared using metal-organic frameworks as sacrificial templates.The morphology and microstructures of CuO@C nanocomposites and MnO@NC nanocomposites were studied and regulated by various microscopic characterization methods,and the lithium ion storage performance was optimized by using them as anode materials for lithium ion batteries.The main results are as follows:Firstly,HKUST-1 precursor was synthesized in the whole water system and characterized by SEM and XRD.Then,HKUST-1 precursor was pyrolyzed at high temperature in argon atmosphere,and finally calcined at low temperature in air to obtain CuO@C nanocomposites.Lithium ion batteries were assembled as negative electrode materials.The results of electrochemical performance test show that CuO@C nanocomposites are used as anode materials.When the current density is 0.1A g^-1,the discharge capacity of the first cycle is 622.5 mAh g^-1,the charge capacity of the first cycle is 612.6 mAh g^-1,and the Coulomb efficiency of the first cycle is 98.41%.CuO@C nanocomposite electrode maintained high charge-discharge capacity after more than 100 cycles.Secondly,Mn-BTC nanowires were successfully prepared.MnO@C nanocomposites were obtained by pyrolysis of Mn-BTC nanowires in argon atmosphere.The effects of annealing temperature on the microstructures of MnO@C nanocomposites were studied.As a negative electrode material for lithium-ion batteries,the best performance materials for lithium-ion batteries were obtained by electrochemical performance test.The results show that the composite obtained by pyrolysis at 800?has the best discharge specific capacity of 714,603,539,483,421,336,672 mAh g^-1 at current densities of 100,200,500,1000,2000,5000 and 100 mA g^-1,respectively.Finally,on the basis of argon-protected pyrolysis of Mn-BTC nanowires,the Mn-BTC nanowires were pyrolyzed in ammonia atmosphere at optimum pyrolysis temperature.The electrochemical properties of MnO@NC nanocomposites were tested,the discharge specific capacity reaching 818,741,651,588,521,411,794mAh g^-1at 100,200,500,1000,2000,5000 and 100 mA g^-1 current densities,respectively.This show that the rate performance of nitrogen-doped composites is further improved.