Ying LI
,
Yunfa CHEN
,
Jianghong GONG
材料科学技术（英文）
The ac conductivities of Y2O3 or CaO-stabilized cubic zirconias were obtained from complex impedance measurements in the temperature range from 373 to 473 K. By analyzing the temperature-dependence of the resultant dc conductivities, it was shown that the activation energies for conduction are lower than those reported previously for the same materials at high temperatures. Comparing the activation energy data with the theoretically estimated values revealed that there may exist a certain, although very small, amount of free oxygen vacancies in the test samples at low temperatures and the conduction in the test samples is a result of the migration of these free oxygen vacancies.
关键词:
Ionic conductivity
,
null
,
null
,
null
A.G.Mostafa
,
M.A.Salem
,
Z.A.El-Hadi
材料科学技术（英文）
Conductivity of glasses in the systems SiO2•PbO•RO, (where R=Ca, Sr or Ba) was investigated between room temperature and 530 K. The dependence of log resistivity as well as the activation energy on the PbO content has been studied. Based on the present experimental results, the possible different conduction mechanisms in such glasses are discussed. It was postulated that Pb2+ ions may represent the major charge carrying species in these glasses. This assumption was confirmed by the calculations of the mean distance between the interstitial Pb2+ ions and the effective center of the O2- ions in the glass networks. The variation in the values of the density and the molar volume with PbO content is also discussed in view of the obtained activation energies for the studied glass-systems.
关键词:
Ionic conductivity
,
null
,
null
步爱秀
,
谭勇
,
方若翩
,
李峰
,
裴嵩峰
,
任文才
新型炭材料
隔膜是锂离子电池的重要组成部分,对隔膜进行材料及结构的优化可以提高锂离子电池的性能.通过在普通商用聚丙烯(PP)隔膜表面构建多孔石墨烯/聚偏氟乙烯功能层的方式获得了复合隔膜材料,通过涂布及常温液相处理的方法调控涂层的孔隙结构,使复合隔膜对电解液的吸附性能明显提高,功能层使复合隔膜具有优异的离子透过性和单侧(石墨烯层)导电性.与采用普通聚丙烯隔膜相比,功能层复合隔膜在低倍率(0.5 C)下的电极材料容量发挥相当.而在高倍率(5 C)下,功能层复合隔膜下,电池容量发挥非常突出,并且600次循环后的容量保持率接近100%,而采用常规PP隔膜,电池材料则容量快速衰减失效.
关键词:
锂离子电池
,
复合隔膜
,
石墨烯/聚偏氟乙烯
,
孔隙结构调控
,
离子电导率
