Research On Hybrid Super-capacitor Based On Two-dimensional Materials

The hybrid super-capacitor is a kind of energy storage device between the battery and the ordinary super-capacitor,having a high theoretical energy density and power density,and good cycle stability.It is a potentially viable energy storage device and has broadprospectsforthedevelopmentofmodernlarge-capacityenergy devices.Two-dimensional materials play an important role in the development of supercapacitor electrode materials due to its unique structure and excellent electrical properties.Therefore,thedevelopmentofhybridsupercapacitorsbasedon two-dimensional materials will help develop high-energy storage systems,and it is of great significance to overcome the scientific problems that cannot be balanced the energy density and power density of traditional energy storage devices.In this paper,two-dimensional materials of graphene and molybdenum disulfide were prepared by redox method and solvothermal method.MoS₂/RuO₂ binary composite electrode materials and rGO/MoS₂/RuO₂ ternary composite electrode materials were prepared by hydrothermal method.In the electrode sheet,another kind of rGO/MoS₂/RuO₂ composite electrode sheet was prepared by multi-layer packaging technology.The prepared samples were subjected to SEM,XRD and other physical characterizationandelectrochemicaltests.Thestructure,morphologyand electrochemical performance is studied in terms of its performance.Finally,the optimized electrode is assembled into an analog hybrid capacitor for charge and discharge testing.The following conclusions are drawn:1.MoS₂/RuO₂ composite electrode materials and electrode sheets are prepared.the addition of molybdenum disulfide materials improves the agglomeration between tantalum oxide materials thorium oxide,and increases the effective contact of the active material and electrolyte in the electrochemical reaction.The area improves the electrochemical performance of the electrode sheet.When the content of conductive agent is 10%,the mass ratio of MoS₂ to RuO₂ is 1:4,the scan rate is 10 mV·s^-1,and the specific capacity of binary composite electrode can reach 413 F·g^-1;the current density at 50 mA/cm²,the average power density reachs 5.05 kW/kg,and the equivalent AC impedance is equal to 0.55?.After 800 cycles,the specific capacity remained at 80%or more.2.In multi-layer packaging technology and the rGO/MoS₂/RuO₂ composite electrode materials,the mass ratio of rGO:RuO₂ in the rGO/RuO₂ composite electrode is1:1 and the mass ratio of MoS₂:RuO₂ in another layer of MoS₂/RuO₂ composite electrode is 1:4,the specific capacitance of the composite electrode can reach 637.4 F/g.At a scan rate of 50 mV/s,the AC equivalent impedance is 0.35?,the average power density can reach 5.2 kW/kg,after 800 cycles.The retention rate is about 78%;In the preparation process of direct hydrothermal synthesis,when the mass ratio of rGO,MoS₂and RuO₂ is 2:1:5 for rGO/MoS₂/RuO₂ composite electrode materials,at scan rate of 10mV/s.The specific capacity is up to 509 F/g,the AC equivalent impedance is 0.28?,the average power density is 4.37 kW/kg,and the capacity retention rate after 800 cycles is84%.In general,the rGO/MoS₂/RuO₂ composite electrode prepared by multi-layer packaging technology is greater than the ternary composite electrode prepared by direct hydrothermal method.Finally,the optimized electrode is assembled into an analog hybrid capacitor for charge and discharge testing.,and its specific energy is up to 657mAh/g,which is higher than the energy density of a common carbon electrode hybrid supercapacitor,but the cycle stability performance is slightly inferior.