The Macro-preparation And Performance Study Of Nano-porous Nickel-copper-manganese Composite Electrode Sheet

With the rapid development of industry,energy crisis and environmental pollution have been highlighted and caused widespread concern.Since then,the exploit and storage of new energy has become one of the current research hotspots.Since the traditional energy storage device cannot meet the demands of power grid and electric vehicles,exploiting novel energy storage devices is even more important.As a new type of energy storage device,supercapacitors has drew more attentions due to the merits of high power density,long cycle lifespan and short charging/discharging time.As an important part of supercapacitors,electrode is the key component to affect the energy storage performance.The transition metal oxides become an ideal choice for electrode materials due to the characteristic of abundant natural reserves and high theoretical specific capacitance,especially in nanoporous structure.However,the poor electrical conductivity of transition metal oxide limits the realization of high specific capacity.Meanwhile,as a whole electrode,the brittleness of nanoporous metal hinders its practical applications.In this paper,we prepared a sandwiched nanoporous NiCuMn/Ni/NiCuMn ternary alloy composite by metallurgically bonding and subsequently dealloying.We also research the atoms arrangement after annealing the nanoporous alloys/polarized nanoporous composites.The novel electrode prepared in our work not only can use sandwiched Ni foil as current collector and supporter,but also enhance the electrochemical performance by the migration of Mn oxides and re-arrangement of atoms on the surface.The research content is shown as follows:?1?According to the phase diagram,the sandwiched Mn-rich alloy(Ni₁₅Cu₁₅Mn₇₀)/current collector?Ni?/Mn-rich alloy(Ni₁₅Cu₁₅Mn₇₀)precursor was prepared by vacuum lap welding,metallurgically bonding and subsequently hot rolling methods.After dealloying,the Ni-supported bicontinuous and nanoporous NiCuMn/Ni/nanoporous NiCuMn alloy was successfully fabricated.?2?Annealing the nanoporous precursor in protection atmosphere can induce surface oxidation?thin layer of metal oxide/oxy-hydroxide?,leading to the migration of Mn and atoms re-arrangement on the surface.XPS characterization shows that the metal elements in the material exist different valence or orbits,while the O element presents three combination peaks?O-metal,OH^-and H₂O?,contributing to forming synergy effect of different elements.?3?The influence of intermediate nickel layer,material thickness,corrosion time,atmosphere and temperature on the electrochemical performance of the electrode were studied.The electrochemical properties of the composite material were tested under different conditions.It was found that after 4 hours of chemical corrosion,the specific capacity of the electrode obtained after annealing at 300?in Ar atmosphere shows the best performance.The specific capacity of the electrode above reach to 1977.97 F cm^-3,which is superior to carbon materials.And the capacitance rate of the electrode is 62.7%,as the current density increases from 1 A cm^-3 to 5 A cm^-3.?4?A symmetric pseudocapacitor is assmebled with two same sized nanoporous NiCuMn/Ni/nanoporous NiCuMn as freestanding anode and cathode.The working potential of the symmetric pseudocapacitor in 1M KOH solution can reach up to 1.8V,which is benefit for enhancing energy density due to E=1/2·CV².At current density of 0.5A cm^-3,the specific capacitance and energy density are 73.31F cm^-3and 24.14m Wh cm^-3,respectively,indicating a good electrochemical property.However,it also suffers some obstacles with aqueous electrolytes,including gas generation and consumption of electrolytes which hinders the long lifespan of the device.