“Significant research strides taken in the past decade have shown that lithium-sulfur (Li-S) batteries are a promising technology to compete with current Li-ion batteries owing to their significantly higher specific energy. However, some fundamental and technical challenges, such as the polysulfide shuttle effect and the need for abundant electrolyte for battery operation, have beleaguered Li-S batteries from being the next practical high-energy-density solution. Recent resurgence of Li-organosulfur batteries as alternative sulfur-based cathode chemistry has shown great potential to alleviate some of these challenges.These materials offer control over the order of the lithium polysulfides formed during cycling through the presence of organic terminal groups, thus minimizing the polysulfide shuttle effect. Additionally, they possess the ability to operate under lean-electrolyte conditions, a critical parameter for maximizing cell-level specific energy.
This work introduces a new member into the family of organosulfur cathode materials – xanthogen polysulfides. Diisopropyl xanthogen polysulfide (DIXPS) was used as a model compound to understand the electrochemical characteristics of this new material class. Its chemical transformations within a battery will be discussed. DIXPS shows excellent long-term performance with stability up to 1,000 cycles at a high rate of 4C. DIXPS also demonstrates the ability to deliver a high specific energy of 1,313 W h kg-1 and 1,694 W h L-1 while operating under high-loading and lean-electrolyte conditions. This illustrates the practical applicability of this material. Additionally, the feasibility of using alternate anodes such as sodium-metal will also be explored. The ability to synthesize such battery materials using natural feedstocks, such as sugars and alcohols will also be examined.
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