Controlling “polysulfide dissolution” and pacifying “polysulfide shuttle” hold the key in developing a lithium–sulfur battery with superior electrochemical performance. Further, exploration of the concept of electrocatalysts plays a significant role in enhancing the electrochemical reversibility of polysulfides in lithium–sulfur battery. Herein, ruthenium nanoparticles-decorated porous, hollow carbon spheres have been successfully prepared and deployed as electrocatalyst as well as sulfur host in the lithium–sulfur battery assembly. Interaction of sulfur with ruthenium nanoparticles has been explained with appropriate electroanalytical and electrochemical characterization techniques. We observe that lithium–sulfur battery containing C–Ru–S cathode with a fixed sulfur loading exhibits a significantly improved capacity of 1200 mA h g–1 at C/10 current rate for 100 cycles. Volume expansion-related issues are found to get addressed by the hollow structured carbon spheres, and the electrocatalytic activity will improve the reaction kinetics of the conversion of Li2S2 to Li2S and vice versa.

Rechargeable lithium−sulfur batteries could be qualified to solve the energy needs of the present society simply by raising the specific capacity of the battery packs and could be made as a cost-effective technology by virtue of the abundant, safe, and economically viable sulfur. However, the polysulfide dissolution related issue in the lithium−sulfur battery is the major hurdle which needs to be reduced prior to the acceptance of rechargeable lithium−sulfur technology as a practically viable and feasible strategy to ensure efficient energy storage mechanisms. Toward this direction, we study the effect of oxidative functionalization and effect of temperature on the cyclability of lithium−sulfur battery as a function of their role in reducing the polysulfide dissolution by using EIS technique. The study demonstrates the reversible cycling of lithium−sulfur battery at 40 °C, wherein the cell delivers a discharge capacity of 750 mA h g −1 at a high current of 750 mA g −1 and tolerates up to 7.5 A g −1 current rate with the 60 wt % sulfur loaded functionalized carbon cathode. Our findings reflect the advantageous effect of surface functionalization on the performance of lithium−sulfur battery and the importance of EIS spectroscopy in understanding the mechanism associated with the reversible electrochemical process.