Lithium-sulfur batteries (LSBs) represent the next frontier of electrochemical storage in the electrification of modern life. While theoretically able to outperform many battery chemistries (due to a theoretical specific capacity of 1675 mA h g^-1_sulfur) current LSB performance has inherent shortcomings due to the self-destructive polysulfide-shuttle.

This research studied a novel templating method by adding removable nanoscale elemental sulfur features to yield network porosity when produced via acidification of aqueous ammonium thiosulfate; this process was carried out within the resole-type polymerisation matrix. Additionally, the inclusion of elemental sulfur within a carbon-sulfur composite was also trialled by acidification of ammonium thiosulfate as a contrast to the standard technique of melting sulfur into a carbon. Further studies were conducted through the addition of lithium phenyl sulfonate (LiPS) groups to improve interactions at the cathode surface.

Materials characterisation included X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM), nitrogen sorptiometry/porosimetry, CHNS elemental microanalysis, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Electrochemical studies performed included galvanostatic discharge-charge (GDC) cycling, electrochemical impedance spectroscopy (EIS) and in operando Raman spectroscopy. Post mortem studies of cycled LSB components were also completed by means of SEM and XPS.

The sulfur-particle-templated carbon (pyrolysed up to 600 °C) was the best performing sulfur-host due to beneficial surface functionality and greater degrees of sulfur-utilisable porosity which was enhanced by deposition-loading of sulfur. That composite led to cells with capacities of 750 mA h g^-1_sulfur after 40 cycles at 0.05 C. Adding a carbonaceous film above the same cathode further improved the interactions near the cathode surface, improving capacities to 1000 mA h g^-1_sulfur after 40 cycles at 0.05 C, but accelerated the polysulfide-shuttle. When grafting LiPS groups on the surface of a porous carbon there was higher power performance without requiring nitrate additive in the electrolyte.