铝电解惰性阳极用Ni-Zn铁氧体的固态合成

采用固态合成法分别在惰性气氛和空气下，制备不同成分的Ni(l-x)ZnxFe2O4铁氧体尖晶石。对反应产物的物相、粒度和形貌的检测表明：在Ar气保护下煅烧主要发生氧化物的离解反应，反应物无法得到目标物相；采用反应烧结法制备铝电解金属陶瓷惰性阳极时，须保持一定的氧分压，以避免金属氧化物的离解和金属相的氧化；在空气中，通过固态反应可制备出理想的铝电解惰性阳极用Ni(l-x)ZnxFe2O4尖晶石，其粒度细，且符合标准正态分布，烧结温度低，在1150℃下保温6h即实现完全反应。     

不同活化方式制备碳电极材料的电化学性能

以碳化后的中间相沥青为原料,分别采用化学活化和物理-化学联合活化工艺制备了超级电容器用活性炭电极材料,对不同活化方式制备的活性炭电极材料的微晶结构、孔径分布、比电容量、循环伏安和交流阻抗特性进行了比较。实验结果表明：采用物理-化学联合活化工艺制备的活性炭电极材料具有更理想的微晶结构和中孔含量。活性炭电极材料的结构与孔隙分布对电性能有明显影响,采用联合活化方式制备的电极材料具有较高的面积比容量、较好的功率特性及较理想的电容特性。     

Electrolysis expansion performance of semigraphitic cathode in [K3AlF6/Na3AlF6]-AlF3-Al2O3 bath system

The electrolysis expansion of semigraphitic cathode in [K₃AlF₆/Na₃AlF₆]-AlF₃-Al₂O₃ bath system was tested by self-made modified Rapoport apparatus. A mathematical model was introduced to discuss the effects of α _CR (cryolite ratio) and β _KR (elpasolite content divided by the total amount of elpasolite and sodium cryolite) on performance of cathode electrolysis expansion. The results show that K and Na (potassium and sodium) penetrate into the cathode together and have an obvious influence on the performance of cathode electrolysis expansion. The electrolysis expansion and K/Na penetration rate increase with the increase of α _CR. When α _CR=1.9 and β _KR=0.5, the electrolysis expansion is the highest, which is 3.95%; and when α _CR=1.4 and β _KR=0.1, the electrolysis expansion is the lowest, which is 1.28%. But the effect of β _KR is correlative with α _CR. When α _CR=1.6 and 1.9, with the increase of β _KR, the electrolysis expansion and K/Na penetration rate increase. However, when α _CR=1.4, the electrolysis expansion and K/Na penetration rate firstly increase and then decrease with the increase of β _KR. Foundation item: Project (2005CB623703) supported by the Major State Basic Research and Development Program of China; Project (2008AA030502) supported by the National High-Tech Research and Development Program of China     

Effects of carbon sources on electrochemical performance of Li4Ti5O12/C composite anode materials

Li₄Ti₅O₁₂/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, and electrochemical performance of Li₄Ti₅O₁₂/C composite materials were investigated by SEM, XRD and electrochemical tests. The results indicate that carbon sources have almost no effect on the structure of Li₄Ti₅O₁₂/C composite materials. The initial discharge capacities of the Li₄Ti₅O₁₂/C composite materials are slightly lower than those of as-synthesized Li₄Ti₅O₁₂. However, Li₄Ti₅O₁₂/C composite materials show better electrochemical rate performance than the as-synthesized Li₄Ti₅O₁₂. The capacity retention (79%) of the Li₄Ti₅O₁₂/C composite materials with starch as carbon source, is higher than that of Li₄Ti₅O₁₂/C composite materials with glucose and sucrose as carbon source at current rate of 2.0C.     

铝电解惰性阳极研究现状

介绍了国内外90年代以后铝电解惰性阳极方面的最新进展，指出了铝电解惰性阳极材料的研究方向和应用前景。     

烧结气氛对5Ni/(10Ni-NiFe_2O_4)金属陶瓷物相组成及力学性能的影响(英文)

在不同烧结气氛下采用冷压烧结法制备5Ni/(10NiO-NiFe2O4)金属陶瓷,通过XRD研究其物相组成,SEM研究其显微结构,并用三点抗弯测试和抗热震实验检测其力学性能。结果表明:在真空气氛及氧含量分别为2×10-5、2×10-4和2×10-3的气氛中均可获得Ni/(10NiO-NiFe2O4)金属陶瓷,但气氛中氧含量对物相含量影响较大。在真空气氛中NiO含量相对较高。材料中NiFe2O4和Ni的含量分别随着气氛中氧含量的上升而增加和减小;在真空烧结气氛中,可获得晶粒尺寸为3.90μm的5Ni/(10NiO-NiFe2O4)金属陶瓷,其抗弯强度可达138.59MPa,且在960°C实验条件下平均抗热震循环次数可达6.67次,具有相对较好的力学性能。     

基于电化学模型的锂空气电池仿真

基于COMSOL仿真平台,建立一维电化学模型,研究放电电流密度、氧气浓度、氧气扩散速率以及Li+扩散系数等因素对电池性能影响。结果表明:当放电电流密度从0.05 m A/cm~2增大到0.5 m A/cm~2时,锂空气电池的放电比容量由1256.4 m A?h/g下降到139.2 m A?h/g;在放电电流密度为0.1m A/cm~2条件下,外界氧气浓度从4.73mol/m~3增加到18.92 mol/m~3时,电池比容量从371.2 m A?h/g增加到1274.5 m A?h/g,表明提高外部环境的氧气浓度有助于提高电池比容量;氧气扩散速率为电池反应的速度控制步骤。当氧气扩散系数从3.5×10-10 m~2/s提高到7×10-9 m~2/s时,电池的容量从373.0 m A?h/g增加到2352.1 m A?h/g;而提高Li+的扩散系数对电池的比容量几乎没有影响。     

新型Bi_(2)O_(3)/ZnFe_(2)O_(4)光阳极的制备及其光电催化降解有机物性能EI北大核心CSCD

采用化学水浴法制备Bi2O3薄膜,并通过电沉积结合后退火工艺在其表面负载ZnFe2O4进行改性,通过XRD、SEM、Raman、XPS、UV-vis等对Bi2O3样品及Bi2O3/ZnFe2O4复合薄膜进行表征。以制备的薄膜作为光电极,研究其光电化学性能,并首次报道其在光电催化降解有机污染物中的应用。结果表明:ZnFe2O4的复合拓宽Bi2O3的吸光范围,提高光吸收系数,抑制光电化学反应过程中光生载流子的复合,从而使Bi2O3/ZnFe2O4复合薄膜在Na2SO4溶液中的光响应电流密度是纯相材料的4倍左右,AM1.5光照下的光电降解亚甲基蓝性能相比于Bi2O3有明显提高。     

Densification of Ni-NiFe204 cermets for aluminum electrolysis

The density of cermet inert anodes in aluminum electrolysis is of great importance. Ni-NiFe2O4 cermets were studied with respect to their densification affected by ball milling time, particle size of raw powders, contents of metallic phase, sintering atmosphere and temperature. The results show that, prolonging ball milling time will increase the density with the optimum value of 150 min; cermets containing 0 - 15 % Ni(mass fraction) have high relative density ranging from 94 % to 96%, but with Ni content increasing, the density slightly decreases; weak reductive atmosphere is favorable to densification; the relative density increases from 80.38% to 96.85% with the sintering temperature increasing from 1 100℃ to 1 300℃ while it decreases at 1 400℃, which may be due to crystal grain coarsening. So the sintering temperature of Ni-NiFe2O4 cerrnets in current work should be controlled at 1 300℃, where the relative density is 96.85 %.