Preparation And Performance Study Of Metal Oxide/C-based Anode Materials For Lithium-ion Batteries

Lithium-ion battery（LIBs）has become an indispensable product in electronic portable products for its high energy density,no memory,as well as fast charging and discharging.It is also predicted that it will become one of the important chemical energy storage mode in the modern high-tech field in the 21st century.The life of battery is longer because users can charge hundreds of times.As an important part of LIBs,anode has a great influence on the capacity of LIBs.The inability of commercial graphite cathodes to meet the growing demand for lithium-ion batteries in electronic devices has prompted researchers to explore various alternatives for higher-capacity anthode materials.1.In this work,the tin ion complexed covalent organic polymers（COFs）are successfully employed as ideal precursors for the preparation of composite materials SnO₂/NCNR with nano SnO₂ embedded within the rod-like N-doped carbonaceous materials.When employed as anode materials for lithium-ion batteries.SnO₂/NCNR-1 exhibited high reversible specific capacity(506 m Ah g^-1 at 0.5 A g^-1 after 600 cycles)owing to its high specific area,high dispersed SnO₂ nanoparticles,recommending SnO₂/NCNR-1 to be a prospective candidate for LIBs.2.High performance of SnO₂/C/G ternary anode material are fabricated by microwave hydrothermal and subsequent sintering method in the presence of humic acid and Super P.The structure,morphology and its electrochemical performances were investigated systematically.The results showed that the addition of HA improved the dispersibility uniformity of the SnO₂ nanoparticles.Electrochemical measurement showed that the SnO₂/C/G anode composites exhibited high retention capacity during charge-discharge cycling as compared to that of binary systems,which was attributed to the good dispersion state and conductivity of SnO₂/C/G.The reversible specific capacity of SnO₂/C/G anode can be maintained at 627.6 m Ah g^-1 after 500 cycles at a current density of 0.5 A g^-1,respectively.3.In this work,CuO/CNT/G ternary composites is obtained by the preparation method in the previous chapter.As the anode material of lithium-ion battery,it exhibits high reversible specific capacities of 949.3 m A h^-1 and 612 m A h^-1 at the current densities of 0.1A g^-1 and 0.5 A g^-1,respectively.The network structure of CNT not only improves the conductivity of composites,but also buffers the volume change of CuO during cycling.The involvement of humic acid promotes the formation of flower-like CuO,and also provides nitrogen atoms that can improve the electronic conductivity of carbon and accelerate the electron transfer of carbonaceous materials.The electrochemical performance of CuO/CNT/G was improved by the synergistic effect of amorphous carbon and carbon nanotubes.