Catecholamine-Functionalized Reduced Graphene Oxide: A Scalable Carbon Host for Stable Cycling in Lithium–Sulfur Batteries

The Lithium–Sulfur battery is a promising high performance battery candidate for large-scale application on account of its high theoretical specific capacity. However, it has come up short on delivering long cycle life mainly due to the formation of soluble polysulfides, which results in the loss of active material during redox processes. In this study, we prepared three different graphene oxide based carbon hosts − graphene oxide (GO), thermally reduced GO (t-rGO) and dopamine-assisted chemically reduced GO (c-rGO) − and investigated their physical and electrochemical properties as a sulfur cathode. We found significant absorbance of polysulfides on the c-rGO host, which provided stable discharge capacity of 601 mAh g⁻¹ at 0.5C for up to 300 cycles. This stable cycling behavior is further identified by in-situ UV–vis spectroscopy and ex-situ X-ray photoelectron spectroscopy, confirming the minimization of polysulfide dissolution toward the electrolyte through the adsorption of polydopamine coating.