Preparation of N-doped graphene powders by cyclic voltammetry and a potential application of them: Anode materials of Li-ion batteries

Abstract

Nowadays, doped graphenes are attracting much interest in the field of Li-ion batteries since it shows higher specific capacity than widely used graphite. However, synthesis methods of doped graphenes have secondary processes that requires much energy. In this study, in situ synthesis of N-doped graphene powders by using of cyclic voltammetric method from starting a graphite rod in nitric acid solution has been discussed for the first time in the literature. The N-including functional groups such as nitro groups, pyrrolic N, and pyridinic N have been selectively prepared as changing scanned potential ranges in cyclic voltammetry. The electrochemical performance as anode material in Li-ion batteries has also been covered within this study. N-doped graphene powders have been characterized by electrochemical, spectroscopic, and microscopic methods. According to the X-ray photoelectron spectroscopy and Raman results, N-doped graphene powders have approximately 16 to 18 graphene rings in their main structure. The electrochemical analysis of graphene powders synthesized at different potential ranges showed that the highest capacity was obtained 438 mAh/g after 10 cycles by using current density of 50 mA/g at N-GP4. Furthermore, the sample having higher defect size shows better specific capacity. However, the more stable structure due to oxygen content and less defect size improves the rate capabilities, and thus, the results obtained at high current density indicated that the remaining capacity of N-GP1 was higher than the others. © 2019 John Wiley & Sons, Ltd.