Lithium-sulfur (Li-S) batteries have attracted substantial attention as next-generation energy storage systems due to their high theoretical energy density and environmental sustainability. However, practical implementation remains impeded by persistent challenges, including polysulfide shuttle effects, low ionic conductivity, and electrode-electrolyte interfacial instability. This thesis systematically addresses these critical issues through the development and characterization of novel electrolyte materials and functional additives. Firstly, a scalable and environmentally benign synthesis approach for nitrogen-doped graphene (N-Gr) is presented, utilizing thermal annealing of few-layer graphene exfoliated via a Taylor-Couette reactor. The synthesized N-Gr demonstrates tunable nitrogen doping, with pyridinic nitrogen functionalities exhibiting significant enhancements in ionic conductivity, polysulfide adsorption capability, and lithium anode stabilization. Experimental results, coupled with computational modeling, elucidate the influence of nitrogen doping modality on electrochemical performance, particularly enhancing battery capacity retention and rate capabilities. Secondly, an innovative in-situ gelled polymer-ceramic electrolyte (POSS-PEG) is developed, integrating the favorable attributes of solid-state electrolytes with the performance characteristics of liquid systems. POSS-PEG electrolyte exhibits high ionic conductivity, effective suppression of polysulfide diffusion, and robust electrode interface stability. Comprehensive electrochemical evaluations, including rigorous pouch cell assessments under varied operational conditions, affirm its superior performance, safety profile, and potential commercial viability. Collectively, this research advances the understanding of electrolyte materials and provides rational, effective strategies to overcome existing limitations, paving the way for the practical realization of safer and high-performing lithium-sulfur batteries.