A novel green and one-step electrochemical method for production of sulfur-doped graphene powders and their performance as an anode in Li-ion battery

Abstract

Graphene-based negative electrodes in lithium-ion batteries have recently been the focus of interest. In this study, sulfur (S)-doped graphene powders in different functionality have been prepared in one step by using Yucel's method for the first time in the literature and they have been used as anode materials of Li-ion batteries. By changing the scanned potential during the preparation of S-doped graphene powders, the graphenic surface is covalently doped by -C-S-C- and -C-SOx-C- (x:2, 3) groups at different amount. When the potential has been scanned in wider potential range (- 1.0 and 2.5 V), 48 sp(2)-hybridized carbon rings have been determined on the powders by using Raman analysis. It is the lowest as 16 for graphenic powder prepared at narrower potential range (1.5 and 2.5 V) and chronoamperometric method. S-doped graphene powders have been investigated by microscopic methods. Electrochemical properties of the prepared S-doped graphene powders and their potential use in Li-ion batteries have been assessed. At a 50-mA/g current density, the 915-mAh/g specific capacity has been determined as the highest discharge capacity in the powder which was prepared by the chronoamperometric method. Specific capacities of 710 mAh/g, 594 mAh/g, and 642 mAh/g have been observed in the powders prepared between - 1.0-(+ 2.5 V), 0.6-(+ 2.5 V), and 1.5-(+ 2.5 V) samples, respectively.