Fe3O4nanoparticle-integrated graphene sheets for high-performance half and full lithium ion cells

Abstract

We synthesized Fe₃O₄ nanoparticle/reduced graphene oxide (RGO-Fe₃O₄) nanocomposites and evaluated their performance as anodes in both half and full coin cells. The nanocomposites were synthesized through a chemical co-precipitation of Fe²⁺ and Fe³⁺ in the presence of graphene oxides within an alkaline solution and a subsequent high-temperature reduction reaction in argon (Ar) environment. The morphology and microstructures of the fabricated RGO-Fe₃O₄ nanocomposites were characterized using various techniques. The results indicated that the Fe₃O₄ nanoparticles had relatively homogeneous dispersions on the RGO sheet surfaces. These as-synthesized RGO-Fe₃O₄ nanocomposites were used as anodes for both half and full lithium-ion cells. Electrochemical measurement results exhibit a high reversible capacity which is about two and a half times higher than that of graphite-based anodes at a 0.05C rate, and an enhanced reversible capacity of about 200 mAh g⁻¹ even at a high charge/discharge rate of 10C (9260 mA g⁻¹) in half cells. Most important of all, these fabricated novel nanostructures also show exceptional capacity retention with the assembled RGO-Fe₃O₄/LiNi_1/3Mn_1/3Co_1/3O₂ full cell at different C rates. This outstanding electrochemical behavior can be attributed to the unique microstructure, morphology, texture, surface properties of the nanocomposites, and combinative effects from the different chemical composition in the nanocomposites.