Effect Of Gold Nanoparticles On Electrochemical Performance Of Carbon Based-electrode Materials

Recent decades have shown that green energy has attracted increasing considered as an alternative energy source owing to the persisting depletion of fossil fuels and the environmental problems related to their use.Supercapacitors have become one of the most promising new energy storage devices due to their high specific power,long cycle life,fast charging/discharge rate,high safety,and relatively cheap.However,the low energy density limits its market application.Activated carbon materials(ACs)have been commonly used as electrode material for supercapacitors attributable to its characteristics,including greater surface area,high porosity,excellent stability,high conductivity,and relatively cheap,but their energy storage capacity is limited.Transition metal compounds can reach a greater capacitance value through the redox faradic,but they often have poor conductivity and poor cycle stability.To combining the advantages and disadvantages of activated carbon and metal oxides,this topic prepares and studies composite materials of activated carbon and transition metal compounds,and studies the effect of nano-gold on the structure and electrochemical behavior of composite electrodes in detail.The basic content mainly includes the followings:(i)The Porous carbon modified by gold nanoparticles(PC@AuNP)was prepared by the chemical activation method.The effect of gold nanoparticles on the electrochemical properties of prepared carbon-based electrode materials was studied.The results confirmed when the current density is 0.5A/g,the composite electrodes displayed the highest specific capacitance of 421.5 F/g compared to pure activated carbon(190.0 F/g)at the same current density and extremely excellent cycle stability.(ii)Hierarchical porous carbon and nickel oxide composites modified by gold nanoparticles(AuNP@PC@NiO)were prepared using in situ reaction method.The effects of gold nanoparticles and nickel oxide on composites structure and electrochemical behavior were studied.The result shows that the AuNP@PC@NiO composites have the highest specific capacitance of 485.7 F/g at the current density of 1.0 A/g and lower charge-transfer resistance than pure NiO.Furthermore,the assembled asymmetric device(AuNP@PC@NiO-0.15/AC)demonstrated a maximum energy density of 19.38Wh/kg at a power density of 152.6 W/kg and a better specific capacity retain of 84.2 percent at a current density of 1.0 A/g after 5000 cycles.(iii)Porous carbon and vanadium nitride composites modified by gold nanoparticles(AuNP@PC@VN)were successfully prepared.Firstly,the gold nanoparticles were introduced into activated carbon using the in-situ reaction method.Then,the VN nanoparticles were incorporated into AuNP@PC composite materials by the hydrothermal method combined with heat treatment.The results show that the composites’ electrochemical properties are greatly improved by introducing nano-gold and VN nanoparticles.Furthermore,the asymmetric supercapacitors device,which used AuNP@PC@VN-0.3 as a negative electrode,had an energy density of 15.0 Wh/kg and a power density of 800.0 W/kg.