Exploring Chlorine Doping of Graphene Oxide Synthesized via Chronoamperometry for Enhanced Sodium-Ion Battery Anode Performance

Abstract

Lithium-ion batteries dominate the landscape of electrochemical energy storage, driving research on sodium-ion batteries to focus on enhancing sustainability and cost-effectiveness through the innovation of advanced electrode materials. In this study, chlorine-doped graphene oxide (ClGO) powders were synthesized as an anode Material for sodium-ion batteries using a straightforward one-step chronoamperometric method. The morphology of the as-prepared sample has been investigated by scanning electron microscopy and transmission electron microscopy. XRD shows that the interlayer distance was increased due to chlorine doping, with an averaged spacing around 0.67 nm of the plane (002). The charge/discharge curves show initial specific discharge capacity of 389.7 mAh.g(-1) at a current rate of 0.1 C. X-ray photoelectron spectroscopy measurements indicate that the powder surface is covalently doped by C-Cl formation. Doping also led to the formation of Cl-containing oxygenated groups -ClOx, (x = 2, 3, 4). Meanwhile, Raman spectroscopy showed that the synthesized powder had double layers with nanocrystalline domain size (L alpha) similar to 49 nm, and the number of sp(2) carbon rings was calculated to be similar to 19. The diffusion coefficient for ClGO determined through electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) measurements, was found to range between 10(-13) and 10(-10) cm(2) s(-1). Besides, the capacity retention for long-term cycling of 100 cycles at 2C rate was similar to 100%. The results show that this ClGO synthesis method presents a promising approach for developing potential, feasible, and tunable carbon-based anodes for Na-ion batteries.