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Li2TiO3 has a broad stoichiometric range and wide application prospects such as cathode, tritium breeder, and microwave dielectric materials. Particularly, Li2TiO3 shows a faster tritium release performance and exceptional chemical and radiation stabilities, making it one of the most promising solid breeder materials. Li-rich Li2TiO3 has been developed for years as an advanced breeder material due to its enhanced tritium production and better stability in hydrogen atmosphere. However, the defect chemistry responsible for accommodating excess Li and how the non-stoichiometry improves the material’s performance is still unclear. In this work, the crystal structure and non-stoichiometry-induced defects in Li-rich Li2TiO3 were investigated by means of X-ray diffraction, electron spin resonance, and X-ray photoelectron spectroscopy. Results show that oxygen vacancies and cation disorder both play a major role in the incorporation of excess Li. The sintering atmosphere (air/vacuum) has a negligible effect on the formation of the non-stoichiometry-induced defects but will influence the concentration of the oxygen vacancies. The better stability in the reduction atmosphere may be ascribed to the oxygen vacancies inside the Li-rich Li2TiO3 crystals. [ABSTRACT FROM AUTHOR]

Li2TiO3 has a broad stoichiometric range and wide application prospects such as cathode, tritium breeder, and microwave dielectric materials. Particularly, Li2TiO3 shows a faster tritium release performance and exceptional chemical and radiation stabilities, making it one of the most promising solid breeder materials. Li-rich Li2TiO3 has been developed for years as an advanced breeder material due to its enhanced tritium production and better stability in hydrogen atmosphere. However, the defect chemistry responsible for accommodating excess Li and how the non-stoichiometry improves the material’s performance is still unclear. In this work, the crystal structure and non-stoichiometry-induced defects in Li-rich Li2TiO3 were investigated by means of X-ray diffraction, electron spin resonance, and X-ray photoelectron spectroscopy. Results show that oxygen vacancies and cation disorder both play a major role in the incorporation of excess Li. The sintering atmosphere (air/vacuum) has a negligible effect on the formation of the non-stoichiometry-induced defects but will influence the concentration of the oxygen vacancies. The better stability in the reduction atmosphere may be ascribed to the oxygen vacancies inside the Li-rich Li2TiO3 crystals. [ABSTRACT FROM AUTHOR]

Lithium titanate with excess lithium (Li2+xTiO3+y) is one of the most promising candidates among advanced tritium breeders for demonstration power plant reactors because of its good tritium release characteristics. However, the tritium breeding ratio (TBR) of Li2+xTiO3+y is smaller than that of e.g., Li2O or Li8TiO6 because of its lower Li density. Therefore, new Li-containing ceramic composites with both high stability and high Li density have been developed. Thus, this study focused on the development of a solid solution with a new characteristic. The solid-solution pebbles of Li2+xTiO3+y with Li2ZrO3 (Li2+x(Ti,Zr)O3+y), designated as LTZO, were fabricated by an emulsion method. The X-ray diffraction patterns of sintered LTZO pebbles are approximately the same as those of Li2+xTiO3+y pebbles, and no peaks attributable to Li2ZrO3 are observed. These results demonstrate that LTZO pebbles are not a two-phase material but rather a solid solution. Furthermore, LTZO pebbles were easily sintered under air. Thus, the LTZO solid solution is a candidate breeder material for super advanced (SA) tritium breeders.

Highlights: [•] Li2TiO3 with excess Li (Li2+x TiO3+y ) was developed as an advanced tritium breeder. [•] Pebble fabrication by the sol–gel method is a promising technique for the mass production of advanced tritium breeder pebbles. [•] To increase the density of the sintered Li2+x TiO3+y pebbles, the sintering temperature was changed. [•] At 1353K, the density of the pebbles increased to approximately 85% T.D. without any increase in the grain size. [Copyright &y& Elsevier]

Li 2 TiO 3 with excess Li was developed as an advanced tritium breeder material for fusion reactors. To improve tritium release performance, the breeder pebbles should have a uniform microstructure with small grains. In this work, Li-rich Li 2 TiO 3 ceramic pebbles were fabricated by an efficient spraying-rolling method and were sintered under air and vacuum atmospheres. Results show that the powder calcination temperature has a significant influence on crush load but negligible effect on grain growth. Excess Li 2 CO 3 in pebbles was not just a lithium source to form the Li-rich phase, but also an effective sintering aid to improve sinterability. Small-grained pebbles with dense and homogeneous structure could be obtained by sintering at a low temperature of 1123 K in air. However, when sintered in vacuum, the pebbles exhibit a porous microstructure with very low crush strength. It is indicated that sintering in air is more suitable for the fabrication of Li-rich Li 2 TiO 3 ceramic pebbles. [ABSTRACT FROM AUTHOR]