(Invited) Binder-Free Sulfur-Carbon Composite Electrodes for High Energy Density Lithium-Sulfur Batteries

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In the scientific mission for sustainable and efficient energy storage solutions, the importance of developing high performance energy storage systems along with environmentally friendly manufacturing technologies has become important. Among various energy storage systems, Lithium-Sulfur (Li/S) batteries are particularly noteworthy for their high theoretical specific energy (2,600 Wh/kg) and cost-effectiveness, traits largely attributable to abundance and favorable properties of sulfur. This positions Li/S batteries as a compelling alternative to the prevalent lithium-ion batteries, setting a new horizon in the pursuit of advanced energy storage solutions. A critical aspect of Li/S battery manufacturing is the fabrication process of sulfur electrodes, traditionally reliant on the slurry casting method with polymer binders like N-Methyl-2-pyrrolidone (NMP), which poses environmental and economic challenges due to the energy-intensive slurry drying and subsequent NMP vapor recovery processes. Although alternatives such as aqueous binders have been explored, they offer limited benefits in reducing the overall environmental impact. Moreover, the use of binders generally increases the resistance of electrodes due to their insulating nature, affecting the electrochemical performance of battery electrodes. Our research marks a significant departure from conventional practices by introducing a novel binder-free and solvent-free approach to fabricate sulfur-carbon composite electrodes. This pioneering method represents a paradigm shift towards green energy technology, addressing both the environmental and economic concerns associated with traditional electrode fabrication. This advancement contributes significantly to reducing the environmental footprint of battery technologies, aligning with the global imperative for cleaner energy solutions. Our comprehensive study focuses on the structural, compositional, and electrochemical characteristics of the binder-free sulfur-carbon electrodes produced through this method. Utilizing advanced spectroscopic and imaging techniques, we examine the mechanisms that underlie the enhanced performance of these electrodes. The investigation reveals critical insights into the morphological and crystalline attributes that promote electrochemical activity, as well as the synergistic interactions between sulfur and carbon in the absence of traditional polymer binder.