Preparation And Properties Of Copper Based Materials In One-dimensional Flexible Supercapacitors

As scientists continue to explore renewable energy,the development of new energy storage methods has attracted the interest of many researchers.In particular,supercapacitor electrode has attracted widespread attention because of their fast charging and discharging speed and long cycle life.Therefore,how to design of an electrode with simple preparation process,low cost and excellent electrochemical performance is of great significance.In this paper,copper wire was used as current collector,CW@Cu_xS electrode was prepared by water bath-heating,CW@Cu O@CNTs electrode was prepared by high temperature oxidation method and chemical vapor deposition method,CW@Cu_xS/Ni-Co LDH electrode was synthesized by water-bath heating and hydrothermal method.The structure of these electrodes was characterized and their electrochemical performance was evaluated.The research contents in detail as follows:(1)Cu_xS nanosheets were grown on copper wires by water-bath heating.The copper wire acts as growth substrate and copper source at the same time,which is beneficial to eliminate impurities.The bond between Cu_xS nanosheet and copper wire is very tight,and the interface resistance is small,its electrochemical performance is excellent.At the current density of 1.2 A/cm~3,the volume specific capacitance of CW@Cu_xS electrode is 3.06 F/cm~3.This electrode has stable cycle stability,after 5000 GCD cycles at a current density of 1.2A/cm~3,capacitance retention rate maintains at about 80%.It has a broad application prospect as high-performance supercapacitor electrode.(2)A simple and efficient high-temperature oxidation method was used to grow highly oriented Cu O nanowires on copper wire,after that,copper particles on Cu O nanocrystalline were produced by chemical vapor deposition method,carbon nanotubes were grown by cracking acetylene gas to obtain CW@Cu O@CNTs electrode.Moreover,it has an ideal specific capacitance and excellent cycle stability,with volume specific capacitance up to6.28 F/cm~3 at current density of 5.0 A/cm~3.After 5000 cycles,the capacitance retention rate of the electrode is 86.11%.Its excellent electrochemical performance is attributed to the good hierarchical structure design of electrode,which provides a new idea for the design of supercapacitor electrode.(3)On the basis of the synthesis of Cu_xS nanosheets,Ni-Co LDH nanowires were deposited on Cu_xS by a hydrothermal method.Ni-Co LDH was interleaved between Cu_xS,forming a conductive cross-linked structure and providing a large number of charge transfer channels.At the same time,Cu_xS nanosheets also have contact with the electrolyte solution,giving full play to the high capacitance characteristics of Cu_xS.The synergistic effect between Cu_xS and Ni-Co LDH make the CW@Cu_xS/Ni-Co LDH electrode excellent electrochemical performance,with volume specific capacitance of 11.47-10.71 F/cm~3 when the current density is 4.0-5.0 A/cm~3.In order to further study the application of CW@Cu_xS/Ni-Co LDH in supercapacitors,parallel supercapacitors were assembled with CW@Cu_xS/Ni-Co LDH as positive electrode and CW@Cu O@CNTs as negative electrode,and their electrochemical performance was tested.The long cycle performance of the supercapacitor is stable,and the capacitor retention rate is 95.59%after 5000 cycles of charge-discharge.A LED with rated voltage of 2.7 V can work continuously for 180 s powered by a circuit,in which six supercapacitors are connected in series and parallel,which fully proves that it has great potential in practical application.