Electrode Design for Lithium-Sulfur Batteries: Problems and Solutions

Pursuit of advanced batteries with high-energy density is one of the eternal goals for electrochemists. Over the past decades, lithium-sulfur batteries (LSBs) have gained world-wide popularity due to their high theoretical energy density and cost effectiveness. However, their road to the market is still full of thorns. Apart from the poor electronic conductivity of sulfur-based cathodes, LSBs involve special multielectron reaction mechanisms associated with active soluble lithium polysulfides intermediates. Accordingly, the electrode design and fabrication protocols of LSBs are different from those of traditional lithium ion batteries. This review is aimed at discussing the electrode design/fabrication protocols of LSBs, especially the current problems on various sulfur-based cathodes (such as S, Li2S, Li2Sx catholyte, organopolysulfides) and corresponding solutions. Different fabrication methods of sulfur-based cathodes are introduced and their corresponding bullet points to achieve high-quality cathodes are highlighted. In addition, the challenges and solutions of sulfur-based cathodes including active material content, mass loading, conductive agent/binder, compaction density, electrolyte/sulfur ratio, and current collector are summarized and rational strategies are refined to address these issues. Finally, the future prospects on sulfur-based cathodes and LSBs are proposed.