Research On Metal Oxide/graphene Lithium Ion Battery Anode Materials

As a kind of green environmental protection battery,lithium ion batteries have high specific energy,high voltage and long cycle life,which has developed rapidly.It has a very broad application in mobile phones,notebook computers,remote control,electric cars and electric bicycle mobile devices.Metal oxide is regarded as a very promising lithium-ion battery cathode materials because of its generally high specific capacity.However,metal oxide anode materials have low electronic and ionic conductivity and metal oxide particles could be easily aggregation in the process of charging and discharging of lithium-ion battery,which have hindered its directly application as the lithium ion battery anode materials.Furthermore,graphene have perfect two-dimensional structure and good electronic and ionic conductivity.Metal oxide/graphene anode material was prepared by in situ synthesis due to the defects of metal oxide in charge-discharge process and the excellent properties of graphene.This method can effectively suppress volume expansion and the resulting poor cycle life of the single metal oxide which was used as cathode material,there are some main results.?1?TiO₂/RGO composites were synthesized by aqueous solution method,the morphology and the electrochemical performance of the materials have been characterized.the results showed that the coulomb efficiency of the TiO₂/RGO composite cathode materials is up to 95.73%for the first time,higher than 91.97%of pure TiO₂.The discharge capacity and capacity retention of TiO₂/RGO composite anode materials is obvious higher than that of pure TiO₂ after 50 cycles,the discharge specific capacity of TiO₂/RGO composite and TiO₂ is 271.6 mAh/g and 208.1 mAh/g,respectivity.The capacity retention rate of TiO₂/RGO composite and the TiO₂ is 89.93%and 89.31%in turn,The excellent electrochemical performance should be attributed to the high electric conductivity and two dimensional nanostructures of graphene.?2?Fe₂O₃/SnO₂/RGO composites have been synthesized by the hydrothermal method,the morphology and the electrochemical performance of the composites with controlling different calcination temperature and mixing Co elements have been characterized,and the results showed that the discharge specific capacity of Fe₂O₃/SnO₂/RGO composite which was calcinated at 300? is 530 mAh/g after 50 cycles,is higher than that of Fe₂O₃/SnO₂/RGO composite calcinated at 250? and 350?.Futhermore,the Co element could limit the electrical conductivity of graphene in composite materials and inhibit Fe₂O₃/SnO₂ metal particle dispersion of graphene layers.