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Flash Sintering Samaria-Doped Ceria–Carbon Nanotube Composites
摘要： Composite ceramic green pellets were prepared by attrition milling a mixture of (CeO2)0.8(Sm2O3)0.2 (samaria-doped ceria, SDC) ceramic powder and carbon nanotubes (CNTs), followed by uniaxial and isostatic pressing. The pellets were sintered inside a dilatometer by applying AC electric fields at 850 °C and limiting the electric current to 1 A, achieving 20.2% final shrinkage. The SDC samples reached 13.3% shrinkage under the same conditions. Higher average grain sizes were measured in specimens flash sintered with CNTs. Impedance spectroscopy analyses show that the specimens flash sintered with addition of CNTs have higher electrical conductivity. Higher delivered Joule heating at the interfaces due to the presence of the electronic conductors (CNTs) are proposed as the main reason for that improvement of the electrical behavior.
关键词： flash sintering,solid electrolytes,carbon nanotubes,impedance spectroscopy,samaria-doped ceria
更新于2025-09-19 17:15:36
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The Influence of the V2O5 · GeO2 Glass Phase on the Properties of AgI Nanolayers
摘要： Using X-ray phase analysis and impedance monitoring, it was shown that for a nanolayered structure, softened glass (V2O5 ? GeO2) can take an imprint from AgI lattice and retain it while being cooled to temperatures below Tg.
关键词： nanolayers,solid electrolytes,phase transitions,interfacial interactions,ionic conductivity
更新于2025-09-10 09:29:36
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Atomistic Insight into Ion Transport and Conductivity in Ga/Al-Substituted Li <sub/>7</sub> La <sub/>3</sub> Zr <sub/>2</sub> O <sub/>12</sub> Solid Electrolytes
摘要： Garnet-structured Li7La3Zr2O12 is a promising solid electrolyte for next-generation solid-state Li batteries. However, sufficiently fast Li-ion mobility required for battery applications only emerges at high temperatures, upon a phase transition to cubic structure. A well-known strategy to stabilize the cubic phase at room temperature relies on aliovalent substitution; in particular, the substitution of Li+ by Al3+ and Ga3+ ions. Yet, despite having the same formal charge, Ga3+ substitution yields higher conductivities (10?3 S/cm) than Al3+ (10?4 S/cm). The reason of such difference in ionic conductivity remains a mystery. Here we use molecular dynamic simulations and advanced sampling techniques to precisely unveil the atomistic origin of this phenomenon. Our results show that Li+ vacancies generated by Al3+ and Ga3+ substitution remain adjacent to Ga3+ and Al3+ ions, without contributing to the promotion of Li+ mobility. However, while Ga3+ ions tend to allow limited Li+ diffusion within their immediate surroundings, the less repulsive interactions associated with Al3+ ions lead to a complete blockage of neighboring Li+ diffusion paths. This effect is magnified at lower temperatures, and explains the higher conductivities observed for Ga-substituted systems. Overall this study provides a valuable insight into the fundamental ion transport mechanism in the bulk of Ga/Al-substituted Li7La3Zr2O12 and paves the way for rationalizing aliovalent substitution design strategies for enhancing ionic transport in these materials.
关键词： Li-ion conductivity/diffusion,enhanced sampling hybrid Monte Carlo,Molecular Dynamics,GSHMC,Ga/Al-substituted LLZO,Solid electrolytes
更新于2025-09-04 15:30:14