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Monoclinic lithium zirconate (m-Li2ZrO3) possess high Li+ conduction, great mechanical and thermal stabilities and chemical inertness against lithium and common nonaqueous electrolytes. This features put these ceramic to practical use as an effective reversible solid sorbent of CO2 at 700?900K and as a promising candidate in tritium breeding material for a D?T fusion power reactors. Also, their main properties allow it to be used as protective coating of silicon-based anode materials or to suppress the dissolution of cathode active materials, such as spinel LiMn2O4 or LiNi0.5Mn1.5O4 at high charge potential [1]. For all these technological applications, Li+ diffusion is a critical factor. Literature data on m-Li2ZrO3 Li+ conductivity is contradictive, being among 10- 6 ? 10-4 Scm?1 over the temperature interval from 300 to 600 °C [2]. Previous experimental and computational studies have shown that the presence of an heteroatom (Fe, Nb, Ce, Al, Ga) in the Zr sites influences the concentration of both lithium and oxygen vacancies, leading to higher Li+ conductivity and lower migration barrier [3]. The present work focuses on the synthesis of Fe-doped m-Li2ZrO3 (Li2Zr0.9Fe0.1O3) via solid-state reaction between Li2CO3, ZrO2 and Fe2O3 as dopant. Following Yasno et al. [4] process, the optimum conditions for obtaining pure undoped m-Li2ZrO3 from Li2CO3:ZrO2 = 1.05:1 was 20 h of ball-milling in ethanol followed by 12 h of thermal treatment at 1000 °C. Taking this into account, in the present work the starting material was a mixture of Li2CO3:ZrO2:Fe2O3 = 1.05:0.9:0.1 and two methodologies were compared: (A) The mixture was ball milled with ethanol (60 rpm) for 20 h and ZrO2 balls (5 mm in diameter). (B) The dry mixture was milled in a high energy planetary milling (800 rpm) for 1 h with ZrO2 balls (5 mm in diameter). For both routs, after the milling, the mixtures were dried and ground until sizes smaller than #100 mesh were obtained. Finally, the samples were treated at 800, 900, 1000 and 1050 °C for 12 h in air, and characterized by X-Ray Diffraction (XRD), Rietveld refinement studies and Mössbauer spectroscopy. The methodology (A) did not allowed obtaining pure Fe-Li2ZrO3. Instead, a mixture of phases was obtained at different temperatures. Probably it is necessary to give energy to the system during the milling to promote the incorporation of Fe inside the structure. Figure 1 (a) shows the XRD patterns of the obtained products for procedure (B) at different temperatures. Heating at 800 and 900 °C conducted to the formation of triclinic-Li6Zr2O7 and monoclinic-Li2ZrO3 phases. The percentages of the phases were not possible to quantify by Rietveld because there is a lack of information about the cell and symmetry of triclinic-Li6Zr2O7 phase. When the temperature was increased to 1000 °C, triclinic-Li6Zr2O7 was transformed to monoclinic-Li6Zr2O7 and Fe-Li2ZrO3 was formed (5.5% and 94.5%, respectively). Similar behaviour of this system was reported in [5] where they indicated that triclinic-Li6Zr2O7 is a metastable phase of Li6Zr2O7. Finally the expected pure product was achieved after 12 h at 1050 °C. The cell parameters obtained from Rietveld refinement studies were: a = 5.417 Å, b = 9.014 Å, c = 5.410 Å and  = 112.675°, similar to prior reported results [6]. Mössbauer spectra (Figure 1 (b)) were fitted by three octahedral Fe environments, two corresponding to Fe3+ (85% and 10%, respectively) and the other to Fe2+ (5%). Taking into account the lattice parameters obatined and that 6-coord. Fe3+ radii (0.64 Å) is smaller than 6-coord. Zr4+ radii (0.72 Å) [3] Fe3+ would be located in Zr sites. In order to study the lithium mobility trough the lattice, percolation energy for lithium ions have been obtained using Bond Valence Theory for different stoichiometries, showing the dependence between the crystallographic environment and lithium mobility. Further studies are setting up to merge experimental and theoretical results in order to develop new materials as high Li+ conductors.