Preparation Of One-dimensional Copper And Cobalt Binary Metal Oxide/sulfide And Their Application In Supercapacitors

Supercapacitors attract much attention for the high power density,fast charge/discharge capability and long-term cycle life.The different materials and morphology of electrodes have demonstrated superior electrochemical properties in producing a high-performance supercapacitor.In particular,binary transition metal compounds have gained significant interest as electrode materials for supercapacitors,owing to the high conductivity,the rich redox states and high theoretical capacities.In this work,we have studied the influence of different morphology of binary transition metal compounds on the electrochemical performance of the supercapacitor.The major research contents and results were shown as followings.?1?One dimensional highly ordered CuCo₂S₄ nanograsses arrays accumulated by nanocrystalline particles were synthesized via a facile hydrothermal method.The rough surface structure can not only contribute to the electrolyte of infiltration and diffusion,but also can increase the contact area between electrode materials and electrolyte.Based on these advantages,the cyclic voltammetry,electrochemical impedance and galvanostatic charge–discharge tests were conducted in three-electrode configurations,the binder-free CuCo₂S₄ electrodes exhibited an ultrahigh specific capacitance of 1852F g^-1 at 2 A g^-1,excellent cycling stability retaining 96%after 4000 cycle at 10 A g^-1,demonstrating a long-term cycling stability and a good rate performance.All-solid-state symmetric supercapacitors were successfully assembled using KOH/PVA as the electrolyte,exhibiting excellent energy density and power density.It obtains a maximum energy density of 31.88 W h/kg at a power density of 3200 W/kg.?2?The cedar leaf-like CuCo₂O₄ was synthesized by a hydrothermal/annealing method.The unique nano-structures were beneficial to shortening the paths ion/electron diffusion,providing a larger specific surface area and exposing richer electroactive sites.The cyclic voltammetry,electrochemical impedance and galvanostatic charge–discharge tests were conducted.As a three-electrode system based on cedar leaf-like CuCo₂O₄,the specific capacitance achieved 1223.2 F/g at a current density of 1.08 A/g,maintained the cycling stability of 88%at a high current density of 10.81 A/g after 2000cycles.All-solid-state symmetric supercapacitors were successfully assembled using KOH/PVA as the electrolyte,exhibiting excellent energy density and power density.It obtains a maximum energy density of 26.52 W h/kg at a power density of 763.75 W/kg and a high power density of 3057.27 W/kg at an energy density of 12.74 W h/kg.?3?The ordered corn-like CuCo₂O₄ was synthesized by a hydrothermal/annealing method.The ordered one-dimensional nanostructure can enhance an effective electron transport.The abundant sub-structure can be used to contribute to increasing a large number of active sites for Faradaic reactions.The cyclic voltammetry,electrochemical impedance and galvanostatic charge–discharge tests were performed.For three-electrode configuration,the specific capacitance achieved 820 F/g at a current density of 2 mA/cm2 and long-term capacity retention of⁹4%after 150 0 cycles.All-solid-state symmetric supercapacitors were successfully assembled using KOH/PVA as the electrolyte,exhibiting excellent energy density and power density.It obtains a maximum energy density of 17 W h/kg at a power density of 480 W/kg.