Advanced Materials Research Vols. 1120-1121

Abstract: A novel polyampholyte P(DMAPMA-co-HEA)-CA was prepared by the quaternization of chloroacetic acid (CA) to P(DMAPMA-co-HEA), which was synthesized by the copolymerization of 2-hydroxyethyl acrylate (HEA) and N-(3-dimethylaminopropyl)maleamic acid (DMAPMA). The isoelectric point (IEP) of P(DMAPMA-co-HEA)-CA was studied by titration, and the salt resistance of P(DMAPMA-co-HEA)-CA expressed by viscosity was determined in sodium chloride solution by Ubbelohde viscometer. The results show that P(DMAPMA-co-HEA)-CA possesses excellent salt resistance in sodium chloride solution.

Abstract: The electrochemical properties niobium dioxide (NbO₂) was investigated as a negative electrode material for lithium ion batteries. The NbO₂ electrode showed a large irreversible capacity and small discharge capacity. The results of X-ray photoelectron spectroscopy indicate that the poor electrode performance of NbO₂ may be caused by niobium pentoxide (Nb₂O₅) formed on the surface of active material. The Nb₂O₅ could be removed by chemical etching to some extent, thus improving the electrode performance.

Abstract: The electrochemical behaviors of a spinel lithium titanate oxide (Li₄Ti₅O₁₂, LTO) electrode during as a novel electrode for calcium ion batteries were investigated during the charging and discharging to understand its electrochemical properties. The electrochemical performance of the LTO electrode was improved by the addition of dimethyl carbonate to the PC-based electrolyte. The initial charge and discharge capacities were ~262 and ~85 mAh g^–1, respectively. The results of the X-ray diffraction analysis showed that the lattice constant of LTO increased after charging, indicating that calcium ions were inserted into Li₄Ti₅O₁₂ during the charging.

Abstract: Pure Al₂O₃-2SiO₂ powders with alkali-activation reactivity were prepared by a sol-gel method. The effects of preparation conditions on alkali-activation reactivity were studied and the optimum preparation conditions were obtained. The results show that calcination temperature is a key factor affecting the alkali-activation reactivity of the powders, while other preparation conditions such as synthetic temperature, the molar ratio of solvents to starting materials and drying time have fewer effects on alkali-activation reactivity than calcination temperature. The structure of the powders was investigated by ²⁷Al magic-angle spinning nuclear magnetic resonance spectra. The data show that the Al₂O₃-2SiO₂ powders with the high alkali-activation reactivity are of high content of 5-coordinated Al and the peaks attributed to 5-coordinated Al are strengthened with the rise of calcination temperature of the powders.

Abstract: LiFePO4 as cathode materials for lithium-ion battery were prepared by a liquid-phase method which utilizes FeSO4•7H2O, NH4H2PO4, H2O2, CH3COOLi and glucose as raw materials. The aqueous can be directly used in the synthesis of FePO4•xH2O without any treatment and the ethanol should be distilled before the synthesis of LiFePO4. The result showed that the high purity of FePO4•xH2O can be achieved even prepared with the aqueous which was used for five times. LiFePO4 cathode material prepared with the distilled ethanol exhibited the best initial discharge capacity of 156.3 mAh•g-1 and the capacity retention ratio 99.49% after 30 cycles at 0.1 C rate.

Abstract: A phase-pure cathode material (Li₂Fe_0.5Mn_0.5SiO₄/C) was successfully prepared by a solid-state reaction. Initially, components used amorphous Li₂SiO₃ obtained from a liquid phase by solidification, FeC₂O₄*2H₂O, MnC₂O₄*2H₂O and glucose as a carbon source. The structure of the prepared cathode material was investigated by X-ray diffraction (XRD), the content of Fe, Mn, Si by Energy-dispersive X-ray spectroscopy (EDX) method, Li content by atomic absorption spectroscopy (AAS), the particle size and morphology by scanning electron microscopy (SEM). XRD data show that the sample on the basis of orthorhombic unit cell can be attributed to Pmn2₁ space group. An analysis of SEM images showed average particles size of about 250 nm. Other results obtained (EDX, AAS) correspond approximately to the theoretical data. Electrochemical performance of the cathode material was gained from cycling between 1.5-4.8V. Discharge capacity after the first cycle reached 220 mAh/g.

Abstract: In recent years, with the rapid development of coal industry, a large number of coal fly ash has been produced, while the recycling rate of the ash is rather low. It is not only a waste of the precious land resources, but also makes environment suffering severe pollution. As an important kind of new material in the national economy, the demand for molecular sieve is growing. It is possible to synthesis molecular sieve using fly ash. The way is not only energy conservation and environmental protection, but also waste reclamation, according with the theme of the sustainable development.This study is to synthesize the molecular sieve with guide agent by the method of hydrothermal synthesis using Cheng He mining area in Shanxi province, which is on the basis of the analysis of chemical composition of fly ash. It is also to find a approach for the use of fly ash with subtly. Through XRD expert zing phase, SEM observing appearance, the characterizing results show that excellent performance molecular sieve of 4A can be synthesized at conditions: Calcined at 850°C and for 2 hours, then hydrothermal reacted with composition of reaction mixture 3Na₂O:1Al₂O₃:2SiO₂: 185H₂O at temperature 90°C, crystallization time 6h with 5% guide agent.

Abstract: The polyacrylonitrile (PAN)-iron octocarboxyphthalocyanine (FePc(COOH)₈) nanofibers were prepared using electrospinning technique and introduced into the interlayer of a carboxymethyl cellulose (CMC)-polyvinyl alcohol (PVA)/chitosan (CS)-polyvinyl alcohol bipolar membrane (BPM), which was characterized using SEM, contact angle measurement, current-voltage characteristics, AC impedance spectroscopy and so on. The experimental results showed that after modification by PAN-FePc(COOH)₈ nanofibers, the membrane impedance of the BPM and its cell voltage were decreased. That indicated that the water splitting efficiency in the interlayer of the BPM was increased. Then the prepared CMC-PVA/PAN-FePc(COOH)₈/CS-PVA BPM was used in the electro-oxidized preparation of dialdehydle starch (DAS). The experimental results indicated that a current density of 20mA·cm^-2 was suitable to obtain high current efficiency. When the electrolysis time was 3h at a current density of 20 mA·cm^-2 , the current efficiency of the CMC-PVA/PAN-FePc(COOH)₈/CS-PVA BPM-equipped cell was as high as 67%.

Abstract: Lightweight foams with open-cell structure are prepared through water-in-oil Pickering high internal phase emulsions (HIPEs), whose density could be low down to 32.5 mg/cm³. The Pickering HIPEs are stabilized by copolymer particles, which also act as the building block for the resultant polymeric foams. The presence of toluene in the organic phase played a key role for the formation of well-defined interconnected pores in the resulting foams. The interconnectivity and the density of the foams could be tailored by varying the particle and electrolyte concentration in aqueous phase as well as the amount of toluene in the organic phase.

Abstract: Polyhedron composed of Mn₂O₃ nanoparticles with an average diameter of 0.5-1.0 μm have been prepared using spent Zn-Mn batteries. The product was characterized by X-ray powder diffraction and scanning electron microscope. The adsorption performance of polyhedron composed of Mn₂O₃ for 2-(5-Bromo-2-pyridylazo)-5-(diethylamino) phenol was investigated. The adsorbent showed high efficiency for the removal of 2-(5-Bromo-2-pyridylazo)-5-(diethylamino) phenol in water. The equilibrium of adsorption was achieved within 40 min. The isotherm adsorption data obeyed the Langmuir model, with a maximum adsorption capacity of 62 mg g^-1.