Sulfur-based polymeric materials were obtained from surplus feedstock; elemental sulfur; and sustainable algae oil, Botryococcene, via inverse vulcanization. Reactions of elemental sulfur and Botryococcene at 185 °C produce polymeric materials with various weight ratios of sulfur and Botryococcene (5:5 to 9:1), depending on the feed ratio. In this study, these polymers have been characterized from several aspects using spectral analysis, thermoanalysis, and electrochemical analysis. When the composition of sulfur is more than 70 wt %, the polymer contains a residual sulfur element not incorporated in the polymer chains. The sulfur-based polymers can be pressed into intended shapes when heated at 120 °C. The polymers could serve as active materials for Li−S batteries. This investigation of structure and properties provides basic information for future applications.