Controllable Preparation Of NiO/TiO₂ Composite Structure And Their Capacitive Properties

Super capacitors have a high energy density, high power and charge-discharge efficiency,long cycle life, environment-friendly, etc. They can be widely applied in the field of electric vehicles, energy, aerospace and defense technology, etc. so the super capacitor have become a hot research topic in the field of scientific research during recent years. In this paper, TNTAs were as the base material, NiO nanoparticles were loaded onto the TNTAs in the basis of different electrolyte systems, and then achieved controllable preparation of NiO/TiO2 composite structure. XRD,SEM,EDS,XPS were carried out to characterize the phase composition, micro structure and morphology of the NiO/TiO2 samples.And there electrochemical properties were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements. The main contents of this paper are as follows:(1) The annealed TNTAs were as a base material, The orthogonal experiments were designed to inveatigate the relationship between the deposition voltage, deposition time, the temperature of the electrolyte and the the morphology and electrochemical properties of the NiO/TiO2 composite structure. The results show that the deposition voltage, deposition time and temperature of the electrolyte have a dramatic effect on the morphology of prepared NiO/TiO2 composite structure, and also have a greater impact on its electrochemical properties. The NiO/TiO2 composite structure which preparaed at-0.7V,50?,400s have the best electrochemical performance, its specific capacitance can up to 11.36 F·g-1 when charge-discharge density was 0.1 A·g-1, and when NiO nanoparticles amount is smaller or particle size is larger can also cause its electrochemical performance reduce.(2) NiO/TiO2 composite structure were prepared by chemical impregnation. In the experiments,the concentrations of nickel nitrate hexahydrate (Ni (NO3)2·6H2O)) and chemical impregnation time were as variable, and studied the relationship between concentration of nickel nitrate hexahydrate,chemical immersion time and the morphology,electrochemical properties of NiO/TiO2 composite structure. The results showed that:as the concentration of the chemical impregnated precursor solution increasing, the morphology of deposited NiO onto the nanotubes is gradually changed from flake to particles, the amount of NiO is gradually increased as immersion time become longer. NiO/TiO2 sample that preparaed at 0.1M,12h condition obtained optimum capacitance. But the cycle stability of the sample is not very good, after 100 cycles it's specific capacitance value only about 50 percent of initial worth.(3) Annealed TNTAs were as a template, NiO/TiO2 composite structure were prepared by chemical bath method and subsequent heat treatment, The experiments studied the relation between the molar ratio of nickel nitrate and urea, as well as concentration of nickel nitrate and the morphology, electrochemical properties of the samples. The results show that:with the nickel nitrate concentration of the precursor solution increased, the deposition morphology of NiO on nanotubes gradually shift from nano branch-like to nano flocculent. With the molar ratio of nickel nitrate and urea in the precursor solution increased, the electrochemical properties of the sample were reduced. When the precursor solution temperature was 90?, and the nickel nitrate hexahydrate concentration 0.01mol/L, nickel nitrate and urea molar ratio of 1:1, after 10h reaction the prepared samples have the best electrochemical performance, which suggesting that a nano branched sample have a greater specific surface area, which provides more electron transport path, and the more capacity for storing electronic.