DBD plasma-assisted coating of metal alkoxides on sulfur powder for Li–S batteries

Sulfur particles coated by activation of metal alkoxide precursors, aluminum–sulfur (Alu–S) and vanadium–sulfur (Van–S), were produced by dielectric barrier discharge (DBD) plasma technology under low temperature and ambient pressure conditions. We report a safe, solvent-free, low-cost, and low-energy consumption coating process that is compatible for sustainable technology up-scaling. NMR, XPS, SEM, and XRD characterization methods were used to determine the chemical characteristics and the superior behavior of Li–S cells using metal oxide-based coated sulfur materials. The chemical composition of the coatings is a mixture of the different elements present in the metal alkoxide precursor. The presence of alumina Al₂O₃ within the coating was confirmed. Multi-C rate and long-term galvanostatic cycling at rate C/10 showed that the rate capability losses and capacity fade could be highly mitigated for the Li–S cells containing the coated sulfur materials in comparison to the references uncoated (raw) sulfur. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) confirm the lower charge-transfer resistance and potential hysteresis in the electrodes containing the coated sulfur particles. Our results show that the electrochemical performance of the Li–S cells based on the different coating materials can be ranked as Alu-S > Van-S > Raw sulfur.