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Abstract: Hydrothermal/solvothermal reactions have been widely used over the years for the low temperature synthesis of inorganic compounds. New twists on such synthesis approaches were developed so as to prepare highly performing phosphate or silicate electrode materials at low cost. Herein we review the use of: (1) “Latent bases” to wisely monitor the reaction and (2) ionic liquids rather than water as reaction media to conduct the solvothermal process. The richness and versatility of such approaches towards the elaboration of a wide class of materials having controlled size and shape is highlighted. Ionothermal synthesis is shown to hold great promises for innovative inorganic synthesis. [Copyright &y& Elsevier]

Owing to cost and abundance considerations, Na-based electrode materials are regaining interest, especially those that can be prepared at low temperatures. Here, we report the low temperature synthesis of highly divided Na-based fluorophosphates (Na2MPO4F, M = Fe, Mn, or mixtures) iii ionic liquid media. We show that this ionothermal approach enables the synthesis of these phases at temperatures as low as 270°C. while temperatures as high as 600°C are needed to obtain similar quality phases by solid-state reactions. Moreover, owing to their highly divided character, Na2FePO4F powders made via such a process show better electrochemical performances vs either Li or Na than their ceramic counterparts. In contrast, regardless of how they were made, the Na2MnPO4F powders, which crystallize in a three-dimensional (3D) tunnel Structure rather than in the two-dimensional (2D)-layered structure of Na2FePO4F, were poorly electroactive. Substituting 0.25 Fe for Mn in Na2Fe1-xMnxPO4F is sufficient to trigger a 2D-3D structural transition and leads to a rapid decay of the materials electrochemical performances. A tentative explanation, based on structural considerations to account for such behavior, is given in this paper. [ABSTRACT FROM AUTHOR]