Effects of functional groups of graphene oxide on the electrochemical performance of lithium-ion batteries

Abstract

Graphene oxide (GO) with different ratios of functional groups are prepared via low temperature direct thermal reduction technology and re-oxidization by nitric acid, respectively. The structural, elemental, and oxygen-containing functional group compositions and electrochemical behaviors of the prepared GO are characterized using Fourier infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy, as well as charge/discharge curves and electrochemical impedance spectra measurements. Compared with graphite and graphene, the enhanced reversible capacity of GO is attributed to the oxygen-containing functional groups and the improved capacities are attributed predominantly to carbonyl and carboxyl groups. Besides, labile oxygen functionalities, such as epoxy groups, have a negative effect on the electrochemical properties, which lower the initial coulomb efficiency of graphene oxide anode materials. These findings may be beneficial to the material design of graphene-based anode materials with a high energy density.