Effect of Hematite Doping with Aliovalent Impurities on the Electrochemical Performance of ?-Fe2O3@rGO-Based Anodes in Sodium-Ion Batteries

The effect of the type of dopant (titanium and manganese) and of the reduced grapheneoxide content (rGO, 30 or 50 wt %) of the ?-Fe2O3@rGO nanocomposites on their microstructuralproperties and electrochemical performance was investigated. Nanostructured composites weresynthesized by a simple one-step solvothermal method and evaluated as anode materials for sodiumion batteries. The doping does not influence the crystalline phase and morphology of the iron oxidenanoparticles, but remarkably increases stability and Coulombic efficiency with respect to the anodebased on the composite ?-Fe2O3@rGO. For fixed rGO content, Ti-doping improves the rate capabilityat lower rates, whereas Mn-doping enhances the electrode stability at higher rates, retaining a specificcapacity of 56 mAhg-1 at a rate of 2C. Nanocomposites with higher rGO content exhibit betterelectrochemical performance.