Performance of surface ionic conduction single chamber fuel cell prepared by the sol gel method

The performance of surface ionic conduction single chamber fuel cell (SIC‐SCFC) prepared by the sol gel method was studied on electric characteristics due to the differences of the operating temperature and humidity, the electrode distance and electrolyte film depth, and multiple cells with the series and parallel connections. The SIC–SCFC was arranged the both anode of Pt and cathode of Au on the boehmite electrolyte. The open circuit voltage (OCV) of single cell achieved a maximum of 530mV in the dry gas mixtures of O₂/H₂=50% in room temperature operation, and but it became decrease as over 60%. The OCV was maintained the constant value between operating temperatures of 30°C to 80°C, and but it was decreased sharply at over 90°C because a humidity on the cell became lower as increasing operating temperature. Then, the cell property was improved to 120°C by adding to the humidity of 70% using a humidifier. The electrode distance and the electrolyte film depth of SIC‐SCFC found to be contributed to the reductions of the cell resistance and the surface roughness on the electrode, respectively. Moreover, the power property of SIC‐SCFC was significantly improved by cell stacks comprised of the series or parallel connection of a cell.     

影响拟薄水铝石烘干系统产能的成因分析及其改进措施

本文针对拟薄水铝石生产线中的关键环节—烘干系统的设备产能问题进行了分析和技术改造,收到了较好的效果,并为同类生产企业及今后改、扩建工作提供了有益的借鉴。     

无机超细粉体改性锂离子电池隔膜的研究进展

综述了近年来无机超细粉体改性锂离子电池隔膜的研究进展,首先介绍了已在锂电隔膜改性上商业应用的Al₂O₃和AlOOH对传统聚烯烃膜和新型静电纺丝膜的改性方法和改性效果,随后又对常规无机材料TiO₂和SiO₂粉体对锂电隔膜的改性进行了叙述,最后对BN等非常规隔膜改性无机材料进行了简介;总结和讨论了无机材料改性后隔膜的组分、结构和性能对锂离子电池综合性能的影响,并对其无机材料改性锂电池隔膜的未来发展趋势进行了展望。     

铝盐沉淀法制备低堆比假一水软铝石的研究

研究了铝盐沉淀法制备假-水软铝石过程中各因素对水合产物物性的影响规律。提出了制备低堆比的高纯假-水软铝石的方法。用NH4HCO3或(NH4)2CO3溶液做洗涤介质有效降低了假-水软铝石中的杂质含量。采用加入晶种的方法制备了低堆比、含有大孔的假-水软铝石。     

Porous mullite ceramics through diphasic gels of large boehmite and small silica particles

Mullite formation process has been studied in stoichiometric mullite (3Al₂O₃·2SiO₂) diphasic gel containing large boehmite (1 m) and small silica (10 nm) particles. It has been found that initial mullitization did not take place inside the silica phase (cristobalite), but took place in the defect -alumina phase. -alumina was stabilized by silica when the temperature was below 1350°C. At temperatures above 1350°C, mullite crystallized directly. It was suggested that silica diffused into the pores (<1.8 nm) of -alumina and prevented the collapse of -alumina pore structure. On the other hand, when silica was not present, the pore structure of -alumina collapsed and -alumina crystallized at 1100°C. Porous mullite ceramics were obtained by using special diphasic gels containing large boehmite and small silica particles.     

Preparation and Characterization of 17O-Enriched Alumina for Nuclear Fusion Damage Experiments

Alumina enriched in ¹⁷O was successfully fabricated from aluminum isopropoxide and water containing the ¹⁷O isotope. This material was necessary for an experiment to study the radiation damage expected in alumina exposed to a nuclear fusion reactor environment. The enrichment levels of specimens subjected to different preparation schedules were measured using a nuclear reaction analysis technique. Replacement of the ¹⁷O isotope in the ceramic by atmospheric oxygen occurred readily. Therefore, successful fabrication of suitably enriched alumina specimens required that all processing steps be performed under vacuum or inertgas environments. The optimum fabrication procedure produced enriched alumina specimens of >99.5% of theoretical density, ∽10-μm grain size, and a flexural strength of 280 MPa.     

Excellent Mechanical and Transparency Properties of Cationic Waterborne Polyurethane Films Modified by Boehmite Sol

The strategies for nanosol from metal alkoxide have enabled production of ultratransparent and mechanically robust polymer nanocomposites at extremely high loading. Herein, a simple approach to fabricate high‐performance polyurethane‐based nanocomposites via unmodified boehmite nanoparticles is reported. Evaluating their physical properties, the uniform dispersion of boehmite in the matrix caused nanocomposites retains ultrahigh transparency. Hydrogen bonding and intermolecular entanglement between boehmite and polyurethane brings about the mechanical properties of the nanocomposites material enhanced, i.e., strength, stiffness, and toughness. Optimized strength, stiffness, and toughness of Boehmite/Cationic waterborne polyurethane at 40 wt% (BNC40) are up to 58.1 MPa, 1096.7 MPa, 249.5 MJ m^?3, respectively. Furthermore, the feasibility and mechanism of polymer strengthening and toughening by inorganic rigid nanoparticles is explored from the aspects of crystallinity and micromorphology.     

Hydrothermal synthesis of boehmites with various particle sizes and transition to α-Al2O3 powders by calcination

Boehmite powders with various particle sizes have been prepared by hydrothermal method and the α-Al2 O3 powders yielded after subsequent calcination have been studied. Dispersive crystalline boehmite powders of 30-100 nm, 0.4-0. 6μm and 1μm in size were obtained respectively by changing the hydrothermal precursors and the pH value of hydrothermal slurry. Calcination of boehmite powders of 30-100 nm at 1250℃ for 1h resulted in the formation of single-phase α-Al2O3,and the products consisted of vermicular particles. The boehmite powders of 0.4-0.6μm were also fully converted to α-Al2O3 at 1250℃, and the products consisted of plate-like particles with the same size of 0. 4-0. 6μm. The boehmite powders of 1μm calcined at 1350℃ for 2h were still composed of a little proportions of transition aluminas besides α-Al2 O3, and the particles sintered severely. The reaction processes for the formation of crystalline boehmites under hydrothermal conditions and α-Al2O3 powders during calcination have been discussed.     

二步法低温制备六铝酸钙/镁铝尖晶石复相陶瓷

以白云石和工业Al(OH)3为原料,采用水热合成和低温煅烧二步法工艺制备六铝酸钙-镁铝尖晶复相陶瓷,探索了水热处理温度对前驱体性能及六铝酸钙/镁铝尖晶石复相陶瓷物相组成和形貌的影响。结果表明:200℃水热处理后的前驱体中,板状三水铝石转变为多孔薄片状薄水铝石;前驱体高温分解后可为复相陶瓷的生成提供高活性原料和六铝酸钙片状形貌的生长空间;二步法工艺可使烧成温度降低100℃以上。白云石添加量为13%时,配料经200℃水热、1 400℃煅烧3 h即可制备出主晶相为六铝酸钙和镁铝尖晶的复相陶瓷,六铝酸钙形貌发育完整,呈交叉片状存在。复相陶瓷的体积密度为1.56 g/cm3,气孔率为61.5%,孔径分布在0.2~1.1μm之间。未水热处理配料于1 500℃保温3 h,制备出六铝酸钙/镁铝尖晶石复相陶瓷,六铝酸钙和镁铝尖晶石晶体衍射峰强度较弱,六铝酸钙片状形貌发育不完整。     

Effect of Ionic Strength on Boehmite Hydrogel Formation

Neutral salts were added to boehmite (γ-AlOOH) sols, and the solution and solution and interfacial chemistries were investigated during hydrogel formation. In general, gel volume increases with higher salt concentrations. Gels form in the presence of salts with monovalent anions when a critical ionic strength is reached, the value of which increases with increasing size of the anion. At the same time, the effect of interparticle distance appears more important with larger anions. The action of divalent anions is more complicated and may involve specific adsorption and complexing with the dissolved aluminum species. The concept of a critical gelation concentration is introduced analogous to the critical coagulation concentration for the flocculation of colloidal particles. The results are interpreted in terms of available models for particle-particle interactions.