An easy and eco-friendly method to prepare reduced graphene oxide with Fe(OH)2 for use as a conductive additive for LiFePO4 cathode materials

Abstract

We developed a green and low cost method to reduce graphene oxide (GO) using Fe(OH)₂ in a protective nitrogen atmosphere in only 15 min at room temperature. The presence of reduced graphene oxide (RGO) was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, thermo-gravimetric analysis, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. It was revealed that Fe(OH)₂, as a reducer, can effectively remove a significant fraction of the oxygen-containing functional groups of GO in this one-step reduction. Considering the analysis results, the reduction mechanism for the synthesis of RGO using Fe(OH)₂ was proposed. With the aid of the conductive RGO additive, the poorly conductive LiFePO₄ showed a good rate performance of 96.7 mA h g⁻¹ at 20 C, as well as an excellent cycling stability. In addition to being environmentally friendly, this time-saving approach was also simple and inexpensive, suggesting the possibility of the large-scale production of RGO, and facilitating the use of graphene-based materials for electrochemical energy storage.