Preparation Of Nanoporous Copper And Nickel Alloys And Their Applications As Electrodes

Nanoporous metals?NPMs?are a new class of functional materials with nanoscale?0.1-100nm?three-dimensional interconnected porous structure and high specific surface area.Due to its combination of functional properties of nanomaterials and structural features of foams,nanoporous metals have found wide applications in the fields of catalysis,sensing,surface Raman scattering enhancement,electrolysis,ultra-capacitors,high-temperature scaffolds,and radiation resistance.Dealloying is an effective method for preparing NPMs by selectively removing one or more active metal elements from the alloy.This method can be widely promoted and applied by obtaining high-performance NPMs through a simple and effective process.This thesis investigated the preparation and application of nanoporous copper?NPC?and nanoporous nickel?NPNi?.Both NPC and NPNi have the advantages of high conductivity and reletively cost effective,and have broad applications in industry.They have the advantages of high conductivity and thermal conductivity of the metal materials,and the low density and high specific area of the porous materials;And their structure could be adjusted by the dealloying method.In this work,the effects of dealloying conditions on the nanoporous structure of dealloyed NPC and NPNi glass ribbon ZrCuAl and ZrTiNiCuAl were discussed.A preliminary study of adjusting the nanoporous size of NPC and NPNi was conducted.In the ZrCuAl system,the HF acid was used as the dealloying agent.The Zr and Al components are completely removed,and the sample is crystallized after dealloying to form a face copper.The effects of dealloying temperature,time and corrosive solution concentration on NPC were analyzed respectively.The dealloying time showed the greatest influence on the structure of NPC.With the dealloying time,the NPC structure showed a coarsening trend:the thickness of NPC increased from³?m to¹4?m,and the average ligament size increased from 41 nm to 170 nm.The NPNi is obtained from the ZrTiNiCuAl system.The pore sizes of the NPNi were between 20 nm-200 nm.The proportion of Ni element is 40%in the original sample,however,it increased to 80%in the NPNi.With the dealloying time increased from 30 min to 150 min,the porosity of NPNi increased from 0.09%to 21.3%.The decrease of the concentration of HF refined the the porous structure of the NPNi.The average pore size decreased from 92 nm at0.05 mol L^-1 to 47 nm at 0.00625 mol L^-1.On this basis,NPC/Cu₂O and NPNi@MnO₂ composite electrodes were prepared from the NPC and NPNi.The NPC/Cu₂O composite electrode exhibits great potential as electrodes for supercapacitors with a maximum specific capacitance of 190.93 F g^-1.In the charge and discharge test,at a current density of 0.8 A g^-1,the specific capacitance was 185.48 F g^-1,the energy density was 26 wh kg^-1,and the power density was 1.3 W kg^-1.Due to the bonding defect between the deposited film and the NPNi,the highest specific capacitance of the NPNi@MnO₂ electrode is only5.23 mF cm^-2.The electrochemical performance needs further improvement.