Nanoporous Electrode Fabricated By Dealloy Aluminum-based Amorphous/nanocrystalline Alloy

Supercapacitors have received extensive attention in virtue of their long-term cycling stability,fast charge and discharge rates,excellent power density,wide range of operating temperatures,and environmental friendliness.Supercapacitors have been boomed benefited from the development of nanostructured materials synthesis.Moreover,it is hopefully used as hybrid electric vehicles,protable electric devices and large industrial equipments.Transition metal oxides(eg,NiO,CoO,MnO2,RuO2and so on)and their compounds can be used as electrode materials for supercapacitors attibuted to their high theoretical capacitance and variable valence.However,the low conductance of electrons in oxides and slow transportation of ions in nanopores limit their performance.The electrochemical performance can be enhanced use flexible amorphous/nanocrystalline alloy as precursor,increase the specific surface area/active sites through regulate structure or morphology and use a simple one-step dealloying method,increase the ion/electron transportability by adding conductive/active metal elements to the mother alloy as well.In this work,study the elactrochemical performance of electrode material using cyclic voltammetry and galvanostatic charge-discharge methods.Analyze the micro-morphology using XRD,DSC,SEM,TEM and BET methods.Discuss the chemical valence of elements in electrode material using XPS method.The contents of this work include hierarchical nanoporous AlNiCoYCu metal/metal-oxide core/shell electrode fabricated by one-step dealloying amorphous alloy ribbons or wires in KOH solutions,then study the influence of the different annealing temperature,the concentration of KOH aqueous solution and the dealloy time to the micro-structrue,morphology and electrochemical performance of this electrode material.In this work,NiCo-contained metal/metal-oxide nanoporous composites are fabricated by one-step dealloying Al82Ni6Co3Y6Cu3 and Al85Fe3Co3Ni3Y3Nd3(at.%)amorphous alloy ribbons or wires in KOH solutions.The micro-structure can be modulate by adjust the annealing temperature,the concentration of KOH aqueous solution and the dealloy time.The capacitance of the dealloyed nanoporous composites reaches 3.35 F/cm~2(about 1522 F/cm~3),which is 3-10 times higher than that dealloyed from as-spun amorphous alloy and crystalline precursors.The large capacitance is attributed to the combination of efficient charge transportation rate and high loading amount of active materials.These results demonstrate that the nanocrystallized amorphous alloys are promising easy-processing precursors for fabricating free-standing nanoporous electrodes with superior capacitance.