Lithium–sulfur battery performance enhancement by optimal loading of graphene oxide on separator with MXene/reduced graphene oxide/sulfur cathode

Lithium–sulfur batteries are a compelling choice for next-generation energy storage devices with their high energy density, low cost, and environmental friendliness. This work employs a one-pot route to synthesize a MXene/reduced graphene oxide/S composite with a graphene oxide (GO)-modified separator to overcome the common bottlenecks to successful commercialization of lithium sulfur batteries like fast capacity fade, low electrochemical utilization, and low sulfur loading. The synthesized cathode material was characterized by powder X-ray diffraction, scanning electron microscopy, thermogravimetry, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical characterization of assembled coin-cells was performed by cyclic voltammetry, galvanostatic cycling as well as by electrochemical impedance spectroscopy. The loading of GO on the separator was varied to probe its effect and a monotonic increase in capacity with increasing GO loading was observed. GO modification of separator also results in lower cell impedance and enhanced Li+ diffusion. The optimized coin cell exhibited an initial specific capacity of 725 mAh/g when cycled at 100 mA/g current density with a capacity fade of 0.14% per cycle. Post-mortem analysis of cycled cells corroborates increased polysulfide trapping with higher GO loading on separator.