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The breeding blanket is a key component of fusion reactors because it directly involves the production of tritium and energy extraction, being both processes critical for the development of self-sufficiency fusion reactor. In current designs, the breeding blanket is formed by the "breeder" (lithium compound), a coolant for heat removal and structural material containing and supporting the breeder [1]. The breeder is responsible to provide tritium by reaction with neutrons and release it to maintain the fuel cycle within the reactor, according to the following reaction:6Li + n → He + T + 4.86 MeV (1)Lithium ceramic such as Li2TiO3, Li4SiO4 and Li2ZrO3 are considered promising candidates to be used as breeding tritium [1]. These ceramics are usually obtained by different methods of synthesis, such as those involving wet phase (auto-combustion in solution, sol-gel, hydrothermal, co-precipitation) or also solid phase (mechanical grinding, heat treatment) [2,3]. The subsequent behavior of the ceramic under service conditions (reducing atmospheres, high temperatures) and under irradiation conditions is strongly dependent on the production processes, the obtained microstructure and the processing of the material. The lithium ceramic must be able to withstand the harsh conditions operating in the breeding blanket (high temperatures, irradiation effects, cyclic mechanical stresses) and show a long-thermal stability and good compatibility with structural materials.In this work, Li2TiO3 powders were synthesized by two different methods, combustion reaction in solution (SCS) and solid-solid synthesis (SS). Both processes were designed to use as raw material Li2CO3 obtained from natural brines. In SCS, an aqueous solution of Li2CO3 and TiO2 as metal precursors, citric acid/tartaric acid as complexing agent/fuel and HNO3 as oxidant, was formed. The mixture was heated to dryness and then to self-combustion. The solid obtained was calcined at 550°C for 12 h to obtain a white powder (see Fig. 1). The resulting material is Li2TiO3 (90 % of monoclinic phase), with minor amounts of TiO2 (rutile) and Li2CO3. In SS synthesis, Li2CO3-TiO2 mixture was mechanically milled in air at room temperature for different times (10 min, 0.5h, 1h, 5 h) and subsequently heat-treated at 400 °C, 600 °C and 800 °C. High yields of Li2TiO3 effect (>95 %) were obtained in all cases. For further study, Li2TiO3 obtained after 1 h of milling and subsequent heat treatment at 600 °C for 24 h was selected to compare its physicochemical stability with Li2TiO3 obtained by the SCS method. Different characteristics of the Li2TiO3 powders produced by SCS and SS methods, such as chemical composition, texture, structure and microstructure, were determined using a combination of Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), N2 isotherms and X-ray powder diffraction (XRPD) analysis. SEM photograph of the powders produced by SS displays a compact morphology (Fig. 1A), homogeneous, with particle sizes lower than 0.7 µm, which are linked and/or sintered. Due to the neck grain growth the shape of the particles is not clear. In opposition, the powders produced by SCS show an open microstructure, with pores clearly identified between the particles (Fig. 1B). The particles have rounded, sharp edges with a wide distribution of sizes from 0.5 µm to 0.1 µm. Several EDS analyses performed on wide areas (200 µm  200 µm) for the samples produced by SCS and SS routes allows to identify the presence of Ti and O. As unique contamination, minor amounts of Si (Si/Ti ratio lower than 2 at.%) are detected in the Li2TiO3 powders produced by SCS method. The grain size calculated from XRPD pattern for the Li2TiO3 (SCS method) was about 70 nm. For the sample milled 1 h and annealed at 600 °C for 24 h or at 800 °C for 5 h, the grain size was 130 nm and 80 nm, respectively. This information evidences that each particle identified by SEM is an agglomeration of single-crystal domains. Regarding the texture, the isotherm for Li2TiO3 produced by SCS is Type II and presents a slight hysteresis, which indicates the presence of macropores (>50 nm) and some mesopores. The specific surface area is 7 m2/g. In the case of SS, it was observed an isotherm type II, without hysteresis and only macropores, with a surface specific area of 4 m2/g. The physicochemical stability of the material under inert and reductive was studied as a function of the temperature using thermogravimetry and temperature-programmed reduction. Powders of Li2TiO3 produced by SCS show a mass loss during heating under inert atmosphere, which could be mainly associated with the decomposition of residual Li2CO3. To stabilize the material, SCS sample was annealed at 800 °C for 5 h up to complete formation of Li2TiO3. This stabilized material was further submitted to TPR using H2(5%)/Ar flow. Minor amount of hydrogen was consumed due to removal of oxygen from Li2TiO3. Then, hydrogen atmosphere promotes the change in the oxidation state of Ti from +4 to +3 and the formation of non-stoichiometric compound Li2TiO3-x. On the contrary, Li2TiO3 powders produced by SS display a stable behavior both under inert and hydrogen atmosphere. The small mass loss detected, which is non-dependent of the atmosphere, is lower than 0.05 %. It could be associated with the elimination of minor amounts of hydroxyl and carbonates groups detected on the surface of Li2TiO3 by Fourier transform infrared spectroscopy (FTIR). An analysis of the advantages and disadvantages of each material is presented.

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