| Lithium ion battery is a kind of secondary battery.During the charge-discharge process,lithium ions migrate between positive and negative electrode and have electrochemical reactions with positive/negative electrode materials.As transition metal oxide,copper oxide has many advantages,such as high theoretical capacity(674mAhg-1),environmental friendliness and simple preparation.However,the low electronic conductivity and large volume expansion during discharge-charge process greatly reduce the cyclic stability of copper oxide.To improve the cycle performances,the normal method is to add carbon materials with high electronic conductivity to copper oxide to form composite electrode.But it is difficult to synthesize the copper oxide tightly integrated with carbon composite with conventional method.In this manuscript,a simple and effective method was developed to prepare copper oxide-reduced graphene composite materials.The specific research process is as follows:First,graphene oxide was prepared with the Hummers method.With cupric chloride as the copper source,alcohol as the reducing agent,and graphene oxide as the carbon source,CuO/rGO composite material was synthesized with hydrothermal method.Different CuO/r GO rates were investigated and the results show that CuO/rGO?25?has the highest capacity and cycle performance.SEM,Raman,FTIR,Zeta-potential were conducted to investigated the surface features and size changes.Different CuO/rGO rate will affect the size,thickness,and the morphology of CuO.Thicker carbon layer increases the diffusion resistance of lithium-ion while thinner carbon layer cannot prevent the volume expansion of copper oxide during charging and discharging processes.CuO/rGO?25?shows excellent electrochemical activity,which retains 550 mAhg-1 after 100 cycles at 0.5 C.With the CuO/rGO?25?composite,a flexible electrode was prepared through electrospinning method,and shows excellent electrochemical performance,which retains the initial capacity after 1000 cycles at1Ag-1. |
PDF Full Text Request