Design, Preparation And Lithium Storage Properties Of Transition Metal Oxide Nanoplates

Lithium-ion batteries which compared with many other energy storage devices have high energy density,long service life,good safety performance and have been widely used in many fields.The anode,as an important part of Lithium-ion batteries,is one of bottlenecks of high capacity battery.However,the traditional commercial graphite anode is hard to meet the growing market demand.The transition metal oxides are one of the new negative electrode materials which have good application prospects.Unfortunately,those materials encounter some problems in the battery cycle.For example,their structure is easy to collapse resulting in low columbic efficiency and fast capacity loss.In order to improve the electrochemical performance of those material as anode materials for lithium-ion batteries,we have designed and prepared the transition metal oxide nanoplates by dealloying method to solve the problems mentioned above.The conclusions are as follows:（1）In order to solve the problem of low capacity of transition metal oxide materials,the Fe₂O₃/TiO₂ composite nanoplates have been designed and prepared by dealloying method.The composite presents a nanostructure.At the current density of 200 mA·g^-1,the material presented stable cycling properties with a reversible capacity of 838.8 mAh·g^-1 after 400cycles.This excellent performance is mainly attributed to the TiO₂ doping in Fe₂O₃,which can effectively improve the reversible capacity of the composites.（2）The Fe₂MnNiCoO_x multiple oxide composite has been synthesized to improve the cyclic stability of the transition metal oxide nanoplates at a large current density.The material had a reversible capacity of 1369.9 mAh·g^-1 after 200 cycles at the current density of 100mA·g^-1.Continuously tested at 300 mA·g^-1 for further 300 cycles,it still delivered a discharge capacity of 1240.2 mAh·g^-1.This excellent performance is mainly attributed to the mutual synergy between multiple metal elements.（3）We have designed and synthesized CoFe₂O₄ bimetallic oxide to develop high capacity transition metal oxides.Under the current density of 100 mA·g^-1,the material delivered a reversible capacity of 2115 mA·g^-1 after 200 cycles.Then the reversible capacity of the material is 1764.5 mAh·g^-1 at the current density of 200 mA·g^-1 for 300 cycles.This high capacity performance is attributed to the more lithium storage sites of bimetallic oxides and nanoscale network structure in the material.The above results show that it is reasonable and feasible to prepare the transition metal oxide nanometers by dealloying as the lithium-ion anode material.This project has great significance for the development of dealloying technology and the research of anode materials for Lithium-ion batteries.