Synthesis of iron-fluoride materials with controlled nanostructures and composition through a template-free solvothermal route for lithium ion batteries

Abstract

A simple template-free solvothermal route has been successfully developed to prepare iron-based fluoride nanostructures with controlled morphology and composition. Fe and F sources, reactant concentration, solvent composition and solvothermal reaction time play important roles in the control of the nanostructures and composition of the products. FeF₃·0.33H₂O hollow nanospheres exhibit high reversible capacities and good cycling performance when used as cathode materials for lithium ion batteries, and the hollow structure has an important impact on the electrochemical performance. In addition, the mesoporous structures within the materials provide an easily accessible system for lithium ion and electrolyte transportation diffusion. The small mesopores in the nanoparticles can also make the electrolyte and lithium ion further diffuse into the interior of the electrode materials and increase the electrolyte/electrode contact area.