The reduction of operating temperature for solid oxide fuel cells (SOFCs) imposes higher requirements on the ionic conductivity of electrolyte materials. CeO₂-based electrolytes have attracted considerable attention due to their superior ionic conductivity in the intermediate-to-low temperature range. However, pure CeO₂ tends to develop electronic conduction under reducing atmospheres, which severely limits its practical application. In this study, CeO₂-based electrolyte materials doped with four rare-earth ions, namely Sm³⁺, Gd³⁺, Y³⁺ and La³⁺, were synthesized via a co-precipitation method. The effects of dopant species on the crystal structure, microstructure, sintering behavior, electrochemical performance and single-cell output performance were systematically investigated. The results indicate that all doped samples form single-phase solid solutions with a cubic fluorite structure. Gd³⁺/La³⁺ doping significantly promotes the densification of CeO₂. Among all samples, Sm- and Gd-doped CeO₂exhibit the highest oxygen vacancy concentration. Sm-doped CeO₂ achieves an ionic conductivity of 0.04 S/cm at 700 ℃, and the single cell based on this electrolyte exhibits a maximum power density of approximately 90 mW/cm², which is substantially superior to those of the other doping systems. This comprehensive study demonstrates that Sm-doped CeO₂ is the most promising electrolyte material among the four systems for intermediate-to-low temperature SOFCs applications.

Lithium orthosilicate ceramics are key tritium breeder materials for the solid‐state tritium breeding blanket of magnetic confinement fusion reactors. The design of their porous microstructure is critically important for enhancing tritium release and extraction efficiency Traditional high-temperature sintering tends to cause grain coarsening, formation of secondary phases, and the closure of open pores, making it difficult to obtain the desired porous microstructure. This work proposes a novel fabrication strategy for porous Li₄SiO₄ ceramics based on a “cold sintering-induced hydrolysis — annealing-driven reactive pore formation” approach. It is found that applying a single condition (either 700 MPa pressure or 300 ℃ temperature alone) fails to fully decompose the precursors. However, the synergistic application of high pressure (700 MPa) and moderate temperature (200~300 ℃) drives the complete hydrolysis of Li₄SiO₄ into Li₂SiO₃ and Li₂CO₃, yielding highly dense green bodies with a relative density as high as 97%. Furthermore, the cold sintering pressure significantly influences the final relative density after annealing, and increasing the cold sintering temperature from 200 ℃ to 300 ℃ transforms the post‐annealing microstructure from macroscopic oriented cracks to uniformly distributed pores. After annealing at 800 ℃, Li₂SiO₃ and Li₂CO₃ in the compact react to re-form Li₄SiO₄, while the simultaneous release of CO₂ gas creates a well‐distributed porous structure within the ceramic matrix. The annealed ceramics exhibit an average grain size of 1.29μm and a relative density of 86%. This study provides a new technical route for the low-temperature fabrication and pore structure design of solid tritium breeder materials.

Hetero-element doped lithium orthosilicates have been considered as advanced tritium breeders due to the superior performances. In this work, Li₄Si_1-xTi_xO₄ ceramics were prepared by proprietary hydrothermal process and multistage reactive sintering. The reaction mechanism of Li₄Si_1-xTi_xO₄ was put forward. XRD and SEM analyses indicate that insertion of Ti leads to lattice expansion, which promotes the grain growth and changes the fracture mode. The compressive tests show that the crush load increases almost four times by increasing x from 0 to 0.2. However, the thermal conductivity and ionic conductivity are the best when x = 0.05 and x = 0.1, respectively. Thermal cycling stability of Li₄Si_1-xTi_xO₄ pebbles was further appraised through investigating the changes of microstructure and crush load. After undergoing thermal cycling, the Li₄Si_1-xTi_xO₄ still show higher crush load compared with Li₄SiO₄, despite Ti segregation in some samples. The x = 0.05 sample exhibits excellent thermal cycling stability. In summary, proper amount of Ti doping can improve the crush load, thermal and ionic conductivity, and thermal cycling stability of Li₄SiO₄.