The Electrochemical Property Research Of Copper Current Collector Modified By Nanostructure

Traditional energy storage and conversion devices,such as lithium-ion batteries and supercapacitors,are based on powder materials which are coated on current collectors to prepare devices.Inactive materials,such as binders and conductive materials will limit the overall energy density and power density.Therefore,growing materials directly on the current collector has outstanding advantages,including a large surface area,a robust combination of the materials and substrate,high specific capacity,and can provide rapid electron/ion transmission for the material.As for materials with large volume expansion,the existing space can buffer the volume change during the electrochemical test.Therefore,self-supporting structure is one of the effective methods to solve the above-mentioned limitations for energy conversion systems.Based on this starting point,the copper current collect was modified by growing nanostructured materials and the performance of lithium-ion battery and supercapacitor was tested.The main research contents are as follows:（1）Copper nanowire arrays were fabricated by a template-assisted electrodeposition method on the surface of copper foil,and then three kinds of Cu-Sn alloys with different structures were obtained by careful treatment of template.Owing to its hollow structure,Cu@Sn nanotubes can effectively alleviate the volume effect of Sn in the internal and external direction,which could be explained as local confinement,showing the most excellent performance.At the current density of 0.8 A g^-1,the capacity could maintain at1193 m Ah g^-1 after 400 cycles.In addition,the full battery assembled with Li Fe PO₄,which can show a high energy density of 148.8 Wh kg^-1.（2）In the previous work,we used a template method to prepare copper nanowires with relatively uniform structure,however,the inconvenient synthesis processes and removal of template limit the productivity and efficiency.So a self-supported sheets-on-wire CuO@Ni（OH）₂/Zn（OH）₂（CuO@Ni Zn）composite nanowire arrays grown on copper foam were successfully prepared.The CuO nanowire backbone provides enhanced structural stability and a highly-efficient electron conducting pathway from the active hydroxide nanosheets to the current collector.The resulting CuO@Ni Zn as the electrode for supercapacitor application delivers a high areal capacitance of 6.56 and 4.18F cm^-2 at a current density of 2 and 50 m A cm^-2,respectively,and a very stable capacitance of 4.03 F cm^-2 at 10 m A cm^-2 for 10000 charge-discharge cycles.Furthermore,a quasi-solid-state hybird supercapacitor（qss HSC）has then been assembled with active carbon,exhibiting a high energy density of about 100.20 Wh kg^-1.Even at the highest power density of 16.26 k W kg^-1,an energy density of 43 Wh kg^-1 can still be obtained.Finally,14 red light-emitting diodes（LEDs）have been lit up by a single qss HSC at different bending states,showing good potential for flexible energy storage applications.