Preparation Of Binary Metal Sulfides And Their Supercapacitor Properties

Supercapacitors?SCs?are an attractive energy storage system due to fast charge and discharge rates,long cycle life and high power density.One of the current challenges is to increase the energy density without affecting power density and cycle life.For a wide range of applications,it is also necessary to solve the problem of cost-effectiveness.This requires a simple preparation method and a cheap and easy to prepare material.An effective solution to improve SC energy storage is the Asymmetric Design?ASC?,which increases energy density by expanding the voltage range.In this study,four metal sulfides were prepared by oven heating and microwave heating,and their electrochemical properties were tested.The results show that the prepared materials are successfully used in supercapacitors.The main research contents of this paper are as follows:?1?The mesoporous cobalt sulfide copper nanoparticles?CuCo₂S₄?electrode materials with high specific surface area were prepared by simple,economical and rapid microwave method.The energy storage effect of the electrode materials was studied in detail by three-electrode and two-electrode systems.The results of the three-electrode show that the specific capacitance is 580 F g^-1 when the current density is 1 A g^-1,and the specific capacitance retention rate is 80%after charging and discharging 2000 cycles at 5 A g^-1,which proves a good cycle.The asymmetric supercapacitor?CuCo₂S₄//AC ASC?with CuCo₂S₄ as the positive electrode and activated carbon?AC?as the negative electrode has a high energy density in the voltage range of 0-1.6 V.At the same time,series asymmetric supercapacitors can drive microelectronic devices.?2?A manganese-cobalt sulfide?MCS?nanosheet electrode material?MCS/NF?containing no binder was prepared by microwave method using foamed nickel as a substrate.Electrochemical performance studies show that the electrode material exhibits excellent energy storage performance,with a specific capacitance of 2084 F g^-1 at 1 A g^-1 and a specific capacitance of 1200 F g^-1 at 100 A g^-1.The asymmetric supercapacitor?MCS/NF//AC?results show a specific capacitance of 134.6 F g^-1 and an energy density of up to 48 Wh kg^-1 at a power density of 240 W kg^-1.This work provides a simple and fast preparation for the electrode material and also provides an innovative idea.?3?The club-like carbon/copper-cobalt sulfide?C@CuCo₂S₄?electrode materials were synthesized by one-step hydrothermal method.The morphology and structural properties of the electrode materials were studied by SEM,TEM,XRD,XPS and EDS.Electrochemical tests show that the carbon material formed by the hydrothermal treatment of glucose can effectively improve the conductivity of the electrode material and is beneficial to energy storage.The charge and discharge test of C@CuCo₂S₄shows that the specific capacitance is 854 F g^-1 when the current density is 1 A g^-1,which is much higher than that of CuCo₂S₄.Asymmetric supercapacitors were assembled using C@CuCo₂S₄ electrodes and activated carbon with a high energy density of 37.8 Wh kg^-1 at a power density of 400 W kg^-1 and a capacitance retention of 96.5%for 7000 charge and discharge cycles at 5 A g^-1.?4?The C@Ni_0.9Cu_0.1-S supercapacitor electrode material was constructed by hydrothermal method,and the influence of glucose on the structure and electrochemical properties was studied in detail.The energy storage effect of the electrode material was studied.The results show that C@Ni_0.9Cu_0.1-S is more excellent than the electrochemical property of Ni_0.9Cu_0.1-S.The specific capacity in the 6 M KOH electrolyte reached 1986 F g^-1 and the potential window was 0-0.49 V.The specific capacitance and energy density of the asymmetric supercapacitor(C@Ni_0.9Cu_0.1-S?AC)with C@Ni_0.9Cu_0.1-S as the positive electrode and AC as the negative electrode are 184.4 F g^-1 and 65.6 Wh kg^-1 with good cycle stability..C@Ni_0.9Cu_0.1-S is expected to be applied to high energy density electrode materials.