Enhanced oxide-ion conductivity of solid-state electrolyte mesocrystals.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanotechnology

Background:

• Development of efficient oxide ion conductors is crucial for electrochemical devices like solid oxide fuel cells.
• Nanostructured cerium oxide (CeO2) offers potential for enhanced ionic conductivity due to increased surface area and grain boundary effects.
• Rare earth doping in CeO2 aims to improve ionic mobility and thermal stability.

Purpose of the Study:

• To fabricate porous oxide ion-conducting films using self-assembled rare earth-doped cerium oxide (REDC) nanocubes.
• To investigate the structural characteristics and ionic conductivity of these mesocrystalline films.
• To explore the influence of Sm-doping on the performance of CeO2-based ion conductors.

Main Methods:

• Evaporation-induced self-assembly of 4-5 nm rare earth-doped CeO2 (REDC) nanocubes onto a substrate.
• Mild calcination at 400 °C to form mesocrystalline porous films.
• Structural characterization of iso-oriented nanocube assembly and measurement of oxide-ion conductivity between 250-350 °C.

Main Results:

• Formation of mesocrystalline structures with iso-oriented REDC nanocubes via {100} face attachment.
• Enhanced oxide-ion conductivities observed in Sm-doped CeO2 (SDC) mesocrystalline films within the 250-350 °C range.
• Correlation of improved electrical properties with high specific surface area and crystallographic connectivity of SDC nanocubes.

Conclusions:

• Mesocrystalline porous films of REDC, particularly SDC, can be fabricated through controlled self-assembly and calcination.
• The mesocrystalline architecture significantly enhances oxide-ion conductivity, attributed to surface-ion conduction mechanisms.
• These findings highlight the potential of self-assembled nanostructures for developing advanced oxide ion-conducting materials.