Preparation And Electrochemical Performance Of SnO 2 -Fe 2 O 3 Based Anode Materials For Lithium Ion Batteries

SnO₂ and Fe₂O₃ have been attracted great interest as anode materials for lithium-ion battery,because of have the advantages of high theoretical specific capacity,rich resources and environment-friendly.However,due to their inherent low electron conductivity and great volume change during charging and discharging,resulting in electrochemical performance is not so ideal.Researchers think there are two ways to solve that,first,synthesis of nanostructures with different morphologies,such as SnO₂-Fe₂O₃ nano hollow spheres,SnO₂-Fe₂O₃ nanoparticles and SnO₂-Fe₂O₃ composite films with three-dimensional porous can reduce the Li+ diffusion distance and buffer volume change by changing the morphology and particle size;second.combined with other materials,such as amorphous carbon,graphene,carbon nanotubes and conductive polymers,these materials can improve the conductivity of SnO₂-Fe₂O₃ to improve the rate performance,also can alleviate the large volume change in the process of charging and discharging.This paper will start with the second method,the specific research is as follows:?1?SnO₂-Fe₂O₃/rGO nanocomposites were synthesized by hydrothermal method using graphene oxide?GO?is the precursor of reduce graphene oxide?rGO?.SnCl₄·5H2O is precursor of SnO₂.FeCl3·6H₂O is precursor of Fe₂O₃.Electrochemical test results shoe that the electrochemical performance of SnO₂-Fe₂O₃/rGO50 nanocomposites is the best.SnO₂-Fe₂O₃/rGO50 electrode at a current density of 160 mA/g.after 100 cycles,the coulombic efficiency is still up to 98%.discharge specific capacity of 596.9 mAh/g,capacity retention rate of about 70%?with the second cycle discharge specific capacity compared to 852.5 mAh/g?;even at high current density of 1A/g,the discharge specific capacity is still 390.4 mAh/g:when the current density was restored to 160 mA/g.the discharge specific capacity quickly recovered to 493.0 mAh/g and then stabilized at about 640.0 mAh/g.SnO₂-Fe₂O₃/rGO50 nanocomposites exhibit excellent cycling performance and rate performance due to the high conductivity and large specific surface area of graphene..?2?SnO₂-Fe₂O₃/MWNTs nanocomposites were synthesized by hydrothermal method using SnCl₄·5H2O is precursor of SnO₂,FeCl3·6H2O is precursor of Fe₂O₃ and adding acidic multi-walled carbon nanotubes?MWNTs?.Electrochemical test results show that the electrochemical performance of SnO₂-Fe₂O₃/MWNTs50 nanocomposites is the best.SnO₂-Fe₂O₃/MWNTs50 electrode at a current density of 160 mA/g,after 200 cycles,the coulombic efficiency is still up to 99%,discharge specific capacity of 513.0 mAh/g,capacity retention rate of about 71%?with the second cycle discharge specific capacity compared to 728.0 mAh/g?;even at high current density of 1 A/g,the discharge specific capacity is 457.9 mAh/g;when the current density was restored to 160 mA/g,the reversible specific capacity quickly recovered to 532.6 mAh/g and then stabilized at about 558.0 mAh/g.The excellent electrochemical performance of SnO₂-Fe₂O₃/MWNTs50 nanocomposites can be attributed to the good conductivity and multi-intercalation sites of carbon nanotubes.