Synthesis of porous C/Fe3O4 microspheres by spray pyrolysis with NaNO3 additive for lithium-ion battery applications

Abstract

In this work, we successfully synthesized porous C/Fe3O4 microspheres by spray pyrolysis at 700ºC with a sodium nitrate (NaNO3) additive in the precursor solution. Furthermore, we studied their electrochemical properties as anode material for Li-ion batteries. The systematic studies by various characterization techniques show that NaNO3 catalyzes the carbonization of sucrose and enhances the crystallization of Fe3O4. Moreover, an aqueous etching can easily remove sodium compounds to produce porous C/Fe3O4 microspheres with large surface areas and pore volumes. The porous C/Fe3O4 microspheres exhibit a reversible capacity of ~780 mAh g–1 in the initial cycles and ~520 mAh g–1 after 30 cycles at a current density of 50 mA g–1. Moreover, a reversible capacity of ~400 mAh g–1 is attainable after 200 cycles, even at a high current density of 500 mA g–1. The wide range of pores produced from the removal of sodium compounds might enable easy electrolyte penetration and facilitate fast Li-ion diffusion, while the N-doping can promote the electronic conductivity of the carbon. These features of porous C/Fe3O4 microspheres led to the improved electrochemical properties of this sample. Graphical Abstract

Nanostructuring silica-iron core–shell particles in a one-step aerosol process

“…The aerosol process has been considered as a more effective and suitable approach for continuous production, holding signicant potential for the rational design and synthesis of various functional nanostructured materials with customized composition and morphology. 7,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Despite its advantages, obtaining pure Fe as a core with a SiO 2 shell poses challenges as the reduction and coating processes unfold in a single system. The determination of precursor and reduction gas concentrations, along with temperature control, is crucial for successfully obtaining pure Fe as the core.…”