Xiuguo Cui

Preparation and Electrochemical Characterization of Mesoporous Polyaniline-Silica Nanocomposites as an Electrode Material for Pseudocapacitors

Mesoporous polyaniline-silica nanocomposites with a full interpenetrating structure for pseudocapacitors were synthesized via the vapor phase approach. The morphology and structure of the nanocomposites were deeply investigated by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis and nitrogen adsorption-desorption tests. The results present that the mesoporous nanocomposites possess a uniform particle morphology and full interpenetrating structure, leading to a continuous conductive polyaniline network with a large specific surface area. The electrochemical performances of the nanocomposites were tested in a mixed solution of sulfuric acid and potassium iodide. With the merits of a large specific surface area and suitable pore size distribution, the nanocomposite showed a large specific capacitance (1702.68 farad (F)/g) due to its higher utilization of the active material. This amazing value is almost three-times larger than that of bulk polyaniline when the same mass of active material was used.

Enhancement in Mechanical and Shape Memory Properties for Liquid Crystalline Polyurethane Strengthened by Graphene Oxide

Conventional shape memory polymers suffer the drawbacks of low thermal stability, low strength, and low shape recovery speed. In this study, main-chain liquid crystalline polyurethane (LCPU) that contains polar groups was synthesized. Graphene oxide (GO)/LCPU composite was fabricated using the solution casting method. The tensile strength of GO/LCPU was 1.78 times that of neat LCPU. In addition, shape recovery speed was extensively improved. The average recovery rate of sample with 20 wt % GO loading was 9.2°/s, much faster than that of LCPU of 2.6°/s. The enhancement in mechanical property and shape memory behavior could be attributed to the structure of LCPU and GO, which enhanced the interfacial interactions between GO and LCPU.

Ultra High Electrical Performance of Nano Nickel Oxide and Polyaniline Composite Materials

The cooperative effects between the PANI (polyaniline)/nano-NiO (nano nickel oxide) composite electrode material and redox electrolytes (potassium iodide, KI) for supercapacitor applications was firstly discussed in this article, providing a novel method to prepare nano-NiO by using β-cyelodextrin (β-CD) as the template agent. The experimental results revealed that the composite electrode processed a high specific capacitance (2122.75 F·g−1 at 0.1 A·g−1 in 0.05 M KI electrolyte solution), superior energy density (64.05 Wh·kg−1 at 0.2 A·g−1 in the two-electrode system) and excellent cycle performance (86% capacitance retention after 1000 cycles at 1.5 A·g−1). All those ultra-high electrical performances owe to the KI active material in the electrolyte and the PANI coated nano-NiO structure.

Synthesis and characterization of full interpenetrating structure mesoporous polycarbonate-silica spheres and p-phenylenediamine adsorption

As a common used and hardly emulsified amorphous thermoplastic, the bisphenol-A polycarbonates were used as the polymer candidate to form a novel monodispersed sub-micrometer mesoporous polymer-silica spheres with full interpenetrating structure. The synthesis procedure was based on a modified sol-gel approach in which the polycarbonate was plasticized in advanced by the surfactant of polymer emulsion. The mesoporous spheres possess a perfect uniform particle size and the polymer-silica spheres are held together by permanent entanglement in three dimensions. The defined crystallization of the polycarbonate was occurred when it was entrapped in the silica laminated matrix due to the plasticizing effect of the surfactant, and directly affected the thermal stability of the mesoporous spheres. The specific surface areas and pore diameters of mesoporous sphere were affected by the mass content and crystallization behavior of the polycarbonate. The p-phenylenediamine was used as adsorbate to investigate the cationic organics adsorption ability of the mesoporous spheres. The results shown that the polycarbonate-silica possess a well adsorption capacity for p-phenylenediamine by virtue of two kinds of hydrogen bond, and the maximum adsorption capacity was nearly 7.5 times larger than that of the hollow mesoporous silica.

New Supercapacitors Based on the Synergetic Redox Effect between Electrode and Electrolyte

Redox electrolytes can provide significant enhancement of capacitance for supercapacitors. However, more important promotion comes from the synergetic effect and matching between the electrode and electrolyte. Herein, we report a novel electrochemical system consisted of a polyanilline/carbon nanotube composite redox electrode and a hydroquinone (HQ) redox electrolyte, which exhibits a specific capacitance of 7926 F/g in a three-electrode system when the concentration of HQ in H2SO4 aqueous electrolyte is 2 mol/L, and the maximum energy density of 114 Wh/kg in two-electrode symmetric configuration. Moreover, the specific capacitance retention of 96% after 1000 galvanostatic charge/discharge cycles proves an excellent cyclic stability. These ultrahigh performances of the supercapacitor are attributed to the synergistic effect both in redox polyanilline-based electrolyte and the redox hydroquinone electrode.

High performance of activated multi-walled carbon nanotube composite electrode in KI redox electrolyte

Abstract High performance electrodes for supercapacitor usually are achieved by compositing conductive and redox materials, the former such as multi-walled carbon nanotubes (MWCNTs), graphene, etc., provide the electrical double-layer capacitances that far less than pseudo-capacitances of the later (metal oxide, polyaniline, and so on). Here, carbonaceous composite electrode of MWCNTs and the redox electrolyte are combined into an electrochemical system for high synergetic effect of capacitance. MWCNT is activated by acid treatment and its structures are characterized by scanning electron microscope, X-ray diffraction, and Infrared spectroscopy analyses. The electrochemical measurements of resultant electrodes showed an excellent synergetic effect. The acid-activated MWCNTs electrode exhibited the maximum specific capacitance of 682 F/g in 0.2 M KI redox electrolytes, which is about 2–20 times larger than MWCNTs and its composite electrode in universal electrolyte without KI.

The preparation and characterisation of the high ordered Ga-SBA-15 with high gallium loading

Abstract The high gallium content and ordered mesoporous Ga-SBA-15 materials were prepared via a direct sol–gel hydrothermal approach. X-ray fluorescence, wide angle X-ray diffraction, nitrogen adsorption–desorption analysis, transmission electron microscopy, small-angle X-ray scattering and scanning electron microscopy are used to characterise the materials, and analysis of these results shows that the structure of these materials with different Si/Ga ratios is excellently ordered. Furthermore, the data of small-angle X-ray scattering and nitrogen adsorption–desorption analysis proved that the wall thickness of mesoporous Ga-SBA-15 materials was decreased by increasing the gallium content. Adsorption of xylene and hydroquinone over the different Si/Ga molar ratios of these materials was explored and the findings showed that SBA-15 did not perform as well.

Synthesis of polyaniline nanostructure with controlled morphology in mixed solvent

Abstract Nanostructured polyaniline was prepared using the template method in the mixed solvent that was composed of dimethyl formamide and distilled water. A series of tests were performed to examine the structural and electrical performance of polyaniline, including X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectrometry, nitrogen adsorption–desorption, cyclic voltammetry and galvanostatic charge–discharge tests. Results indicated that the mixed solvent could lead to a different morphology and influence the electrical performance of polyaniline in the system. The specific surface area of polyaniline was greatly improved and the electrical properties were enhanced correspondingly.

Synthesis of thick-walled SBA-15 in PEO27-PPO61-PEO27 template under relative low temperature and acidity

Thick walled (7.7 nm) SBA-15 has been synthesized by using PEO 27 -PPO 61 -PEO 27 (P104) as template under relative low temperature and acidity. SAXS, nitrogen sorption experiments and TEM have been utilized to characterize resultant materials.

Synthesis of tetrakaidecahedronal SBA-16 by acidity adjusting

Tetrakaidecahedronal SBA-16 (cubic Im 3 m) has been synthesized in PEO 106 -PPO 70 -PEO 106 ( F127 ) template solution without inorganic salt by adjusting acidity at low temperature. Due to the pH-dependence of mesoporous silica morphology, the shapes of resultant materials show an evolution from irregular sphere → dodecahedron → tetrakaidecahedron → irregular shape as the acidity increases.