Preparation And Supercapacitor Performance Of Tungsten-based Nanorod Arrays

Supercapacitors（SCs）have emerged in much advanced renewable energy equipment in recent years due to their excellent safety,superior cycling stability,high power density,and environmental protection.However,the low energy density of commercial SCs is not enough to support a long-term energy consumption system,so it is emergence to develop electrode materials with both high specific capacitance and a wide potential window.Doping is an effective strategy for adjusting the crystal structure of materials,creating more active sites for energy storage.Among them,non-metal doping has been extensively studied,but the enhancement mechanism of metal compounds by cation doping with trace amounts is still unclear.Herein taking tungsten-based nanomaterials as the research object,we prepare two nickel-doped tungsten-based transition metal compound electrodes,and material characterization and supercapacitor performance were carried out to confirm,as follows:The different nickel-doped tungsten oxide nanorod array electrodes（Ni-WO₃）were prepared by hydrothermal method using carbon cloth as a substrate,and the effect of Ni doping on the performance of supercapacitors was discussed.The results show that when the current density is 10 m A cm^-2,Ni-WO₃ with 4%doping concentration shows the most excellent charge storage performance,and the area-specific capacitance can reach 4206 m F cm^-2,which is far better than pure WO₃.The capacity(910 m F cm^-2)proves that Ni doping improves the charge storage capacity of WO₃.To further confirm the practical value of Ni-WO₃ electrodes,an asymmetric solid supercapacitor（PPy//Ni-WO₃ ASC）was successfully assembled.The maximum area-specific capacitance of the ASC device under the voltage window of 1.3 V is 313.8 m F cm^-2,and the maximum energy density of 72.3μWh cm^-2 can be reached at a power density of 2.6m W cm^-2.The results show that h-WO₃nanorods are an excellent high-performance supercapacitor electrode material.Tungsten nitride and Ni-doped WN nanoarrays（Ni-WN）were prepared by high-temperature nitriding method using WO₃ nanorods array as a precursor.The results show that the electrochemical performance of various Ni-WN electrodes is better than that of pure WN electrodes,indicating that a small amount of nickel doping can optimize the energy storage properties.At the same time,4%Ni-WN exhibits excellent cycling stability with the capacity retention of 95.65%after 5000cycles.An asymmetric supercapacitor was successfully assembled by employing PVA/H₂SO₄ as gel electrolyte,PPy as positive and 4%Ni-WN as negative electrode,which delivers a superior energy density/power density of 11.97μWh cm^-2/2.0 m W cm^-2.The results show that Ni-doping can significantly enhance the supercapacitor performance of tungsten-based electrode materials.