Synthesis And Electrochemical Li-storage Performance Of Tin Dioxide And Carbon-based Composites

lithium ion batteries have been paid much attention by researchers at home and abroad because of their excellent electrochemical performance.and It is also the most potential energy storage device for new energy vehicles.As one of part of lithium ion battery.the lithium storage performance of anode material has a direct impact on the performance of the whole battery,so it has been the focus of attention of researchers and producers.metal oxide SnO₂ with high specific capacity,low toxicity and low cost has become the most potential substitute material for graphite materials.However,it also has some inevitable disadvantages,researchers at home and abroad have launched a series of works around its shortcomings.In this paper,taking SnO₂ as the research center.SnO₂ modification study was carried out by the two aspects of changing the morphology and combineing with carbon materials to improve the electrochemical performance.details are as follows.Taking carbon nanotubes with initial treatment as as containers,solution containing Sn2+ was filled into the empty channels of carbon nanotubes due to surface tension and capillary action,the SnO₂ nanoparticles were grew as a result of in situ oxidation reduction reaction and a series of SnO₂@OCNTs?8 h-100 h?composites were synthesized by controlling the reaction time.The physical and chemical tests of TG and TEM showed that the number of particles in carbon nanotubes was increased with the increase of filling time.the results is in agreement with the electrochemical test results.when the reaction time was 100 h,SnO₂@OCNTs?100 h?showed the best lithium storage performanc in terms of an high initial capacity of 2200 mAh g-1 at the current density of 78 mA g-1,excellent rate performance?804 mAh g-1 at 0.4 A g-1after 50 cycles?and long cycle life?674 mAh g-1 at 4 A g-1after 200cycles?.Using PVP/SnCl₂ solution as precursor,The PVP/SnO₂ nanofibers with different diameters were prepared by electrospinning technique of controlling the spinning parameters such as voltage and concentration.and SnO₂ nanofibers were obtained by heat treatment.than physically mixing it with graphene oxide GO,three kinds of SnO₂/rGO composites with different diameters were prepared by heat treatment and ultrasonic treatment.a series of phase characterization and electrochemical characterization were carried out.The electrochemical results show that the smaller the diameter of the SnO₂ nanofibers,the better electrochemical performance of the composite.the SnO₂?2%?/rGO composites release a super high discharge capacity?1987 mAh g-1 at 0.4 A g-1 after 50s?and long cycle life?649 mAh g-1 at 4 A g-1after 1000 cycles with 99.9% coulombic efficiency?.