| In recent years,red phosphorus,as an anode of lithium ion batteries and sodium ion batteries,showing an excellent lithium/sodium storage performance.Red phosphorus with high theoretically specific capacity of 2596 mAh g-1 is considered to be a potential anode material.However,the red phosphorus anode with non conductivity has a strong volumetric effect?300%?during insertion/de-insertion of Li+,resulting a shortened life of the secondary batteries.And this has a negative impact on its application in the energy storage devices.Graphene have been widely used in energy storage devices due to its good electrical conductivity.And it shows a promising future.Based on the previous study,the graphene-based red phosphorous composite was first prepared by electrostatic spraying and light wave reduction method.It is expected to get a new composite with cooperative formation of graphene and phosphorus to improve the performance of lithium-ion battery and sodium ion battery.In addition,the application of graphene nanoribbons in lithium ion batteries with the similar method was also studied at the first time.Main works are as follows:1.The red phosphorus/graphene composite with different proportions of 20%,40%,60% of red phosphorus/graphene composite films were prepared by electrostatic spraying and a rapid wave light reduction: 20%/ES-RP/rGO,40%/ES-RP/rGO,60%/ES-RP/rGO.They were characterized by XRD,FTIR,Raman spectroscopy,XPS,SEM and TEM.The results show that a 3D lamellar conductive structure was made through the electrostatic spraying.Red phosphorus particals with small size were evenly distributed on the surface of the graphene.2.Different proportions of red phosphorous/graphene composite film electrodes were assembled into lithium ion batteries.The electrochemical performance of were studied.The results show that the RP/rGO composite has a better property than rGO.Among them,40%/ES-RP/rGO composite performes the best.At a current density of 0.37 A g-1,the first capacity of 2391.7 mAh g-1 with a coulomb efficiency of 94% is exhibited.At the current density of 1 A g-1,the capacity retention is up to 95% after 100 cycles.Even at a higher current density of 10 A g-1,there is still has a capacity of540 mAh g-1.What's more,the capacity retention is up to 92% at a different current density.3.The different proportions of red phosphorous/graphene composite film electrodes were assembled into sodium ion batteries.The electrochemical performance were studied.The results show that,electrochemical performance of sodium ion batteries were improved greatly after the combine of graphene and red phosphorus.As a result,40%/ES-RP/rGO composite has a better performance compared with the rest of materials in this experiment.At a current density of 0.1 A g-1,it shows a high capacity of 4270.1 mAh g-1 with a first coulomb efficiency of 73%.At another current density of 1 A g-1,the reversible capacity can aslo up to 1154 mAh g-1 after 100 cycle.At a different current densities from 0.5 A g-1 to 0.5 A g-1,there is still 92% of the capacity is maintained after 90 cycles.4.The graphene nanoribbons?GNRs?film electrodes were prepared by electrostatic spraying,and its electrochemical properties were studied.The results show that GNRs delivers a rather high specific capacity of 4453.8 mAh g-1 at 0.1 A g-1,with the first coulomb efficiency of 69% for lithium ion batteries.After 100 cycles,a capacity of 1717.14 mAh g-1 is retention.What's more,the material keeps a reversible capacity of 610.5 mAh g-1 at a higher current density(37.2 m Ah g-1).The results demonstrate that the ES-GNRs material obtained by electrostatic spraying has excellent electrochemical properties.5.The preparation mode of film electrode obtained from the electrostatic spraying directly avoids the adding of the conductive agent or binders.At the same time,this method prevents an overlapping of graphene.The results will provide a direct theoretical support and basis for the research on new energy storage electrodes and the development of graphene composites. |
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