Structural and electrochromic properties of Fe$_{2}$(SO$_{4})_{3}$ nanostructures prepared by template assisted method

Oxides containing polyanions such as XO$_{4}^{2-}$ (X = S, Mo, P and W) as lithium insertion hosts are promising cathode materials due to their high thermal stability. However, the larger separation of the transition metal ions can be expected to reduce the electron mobility. As observed in LiFePO$_{4}$, this can be overcome either by coating the cathode materials with carbon or by decreasing the particle size. We have prepared nanowires of NASICON type structure and platelets of monoclinic Fe$_{2}$(SO$_{4})_{3}$ by template assisted electro deposition. These structures were grown on stainless steel substrates and are characterized by XPS, HRTEM, and XRD analysis. Both NASICON and monoclinic Fe$_{2}$(SO$_{4})_{3}$ structures are very porous and are comprised of nanoparticles leading to a high lithium insertion capacity.