Based on the previous work conducted by Fujii et al., NdBaInO4 compounds present modest oxide-ion conductivities. Therefore, it has been an attractive system of significant interest. In this study, we attempted to partially substitute Ca for Nd and the total electrical conductivity was successfully improved due to the generation of oxygen vacancies. The synthesis, crystal structure, density, surface topography, and electrical properties of NdBaInO4 and Ca-doped NdBaInO4 have been studied, respectively. NdBaInO4 and 10% and 20% molar fractions of Ca-doped NdBaInO4 were synthesized through solid-state reactions. The crystal structure of them was obtained from Le Bail refinement of the XRD pattern, giving the result of the monoclinic structure, which belongs to P21/c space group. The highest total electrical conductivity of 4.91 × 10−3 S cm−1 was obtained in the Nd0.9Ca0.1BaInO3.95 sample at a temperature of 760 °C in the dry atmosphere and the activation energy was reduced from 0.68 eV to 0.58 eV when the temperature was above 464 °C (737 K) after doping the NdBaInO4 with a 0.1 molar fraction of Ca2+. Moreover, the total conductivity of Nd0.9Ca0.1BaInO3.95 in the wet atmosphere at moderate temperature was relatively higher than that in the dry atmosphere, which suggests that potential proton conduction may exist in wet atmospheres. In addition, the oxygen diffusion coefficients of Nd0.9Ca0.1BaInO3.95 (D* = 1.82 × 10−8 cm2/s, 850 °C) was about two times higher than that of Nd0.8Ca0.2BaInO3.90 (D* = 7.95 × 10−9 cm2/s, 850 °C) and was increased significantly by two orders of magnitude when compared with the oxygen diffusion coefficient of the undoped NdBaInO4 (D* = 8.25 × 10−11 cm2/s, 850 °C).
随着环境污染和能源危机的加剧,锂离子电池市场化进程得到了极大的推动.锂离子电池比容量大、效率高、寿命长以及无污染等特性优点使其成为电子市场的首选电源,在混合动力汽车和电动汽车等可持续电力系统中也发挥着重要作用[1-3].近年来,电动汽车行业的快速发展对锂离子电池的各项性能提出更高要求,现有锂离子电池能量密度较低的限制阻碍了其大规模应用,新一代高效锂离子电池的开发迫在眉睫.国内外研究人员对锂电池的正负极材料、隔膜材料、电解质材料等展开了探索研究[4-7].
软硬度是复合材料预浸料的重要工艺性能之一,国内外一直缺乏预浸料软硬度的定量表征方法.本文自行研制了软硬度设备,通过将预浸料在固定直径芯轴上悬垂距离来定量表征预浸料的软硬度,研究了芯轴直径、试样长度、放置时间等因素对软硬度的影响,确定了最佳参数并建立测试方法.通过对同规格不同批次预浸料、不同规格预浸料以及不同外置时间预浸料的软硬度测试进一步对测试方法进行了验证.结果表明:对不同批次间预浸料软硬度数据度差异较小,该方法测试状态稳定;对不同规格下预浸料的软硬度,该测试方法能够有效区分;对同一材料软硬度测试方法能够定量表征出不同外置时间下软硬度的变化趋势;说明该测试方法是合理可行的.
