Production of Sulphur-Doped Graphene Oxide as an Anode Material for Na-Ion Batteries

Abstract

Sodium-ion batteries have been the focus of interest in recent years due to abundance and cost-effectiveness of sodium resources globally as opposed to lithium. In this work, sulfur-doped graphene oxide (SGO) was synthesized using a straightforward, one-step, cost-effective, and eco-friendly chronoamperometric method at room temperature. The resulting powder was then utilized as active anode material for Na-ion batteries. The surface of the synthesized SGO powder, which consists of approximately three layers with 19 sp2 hybridized carbon rings and a domain size of about 50 nm, is covalently doped with –C-SOx-C- (x = 2,3) groups. The deduced diffusion coefficient from electrochemical impedance spectroscopy and galvanostatic intermittent titration technique measurements for SGO as anode in NIBs is in the range of 10−11–10−12 cm2.s−1. At 0.1 C rate, the initial discharge capacity recorded 256.7 mAh.g−1 at 0.1 C rate. In addition, the capacity retention for long-term cycling of 100 cycles at 2 C rate was 99.85%. The unique structure of SGO allows us to achieve satisfactory anode performance in capacity and rate capability, with potential for further enhancement.