Catalytic materials for lithium-sulfur batteries: mechanisms, design strategies and future perspective

Adsorption‐Catalysis‐Conversion of Polysulfides in Sandwiched Ultrathin Ni(OH)2‐PANI for Stable Lithium–Sulfur Batteries

“…Hence, the adsorption and catalysis work synergistically to suppress the shuttle effect and improve the electrochemical performance of Li–S batteries. [ 23 ]…”

“…Hence, the adsorption and catalysis work synergistically to suppress the shuttle effect and improve the electrochemical performance of Li-S batteries. [23] In this work, we report a sulfur cathode based on ultrathin Ni(OH) 2 and polyaniline (PANI) (Ni(OH) 2 @S@P) for highperformance Li-S batteries. Specifically, the hollow and soft PANI core reacts with sulfur to form a cross-linked, structurally stable sulfur-PANI backbone through in situ vulcanization, providing strong interconnection with LiPSs to chemically anchoring active materials.…”

Engineering a TiNb2O7-Based Electrocatalyst on a Flexible Self-Supporting Sulfur Cathode for Promoting Li-S Battery Performance

“…3 Although the mechanism of the sulfur cathode REDOX reaction is still uncertain, the reduction mechanism of S 8 → Li 2 S 8 → Li 2 S 6 → Li 2 S 4 → Li 2 S 2 /Li 2 S and the reverse step in the charging process are generally accepted at present. 4 First, solid S 8 undergoes reduction to form a series of soluble long-chain LiPSs (S 8 → Li 2 S 8 → Li 2 S 6 → Li 2 S 4 ). As the reaction proceeds, these long-chain LiPSs decompose into solid Li 2 S 2 /Li 2 S. 4 The slow conversion process between soluble long-chain LiPSs and insoluble Li 2 S 2 /Li 2 S during charge and discharge causes soluble long-chain LiPSs to dissolve in the electrolyte and then shuttle between the cathode and anode by a concentration gradient.…”

“…4 First, solid S 8 undergoes reduction to form a series of soluble long-chain LiPSs (S 8 → Li 2 S 8 → Li 2 S 6 → Li 2 S 4 ). As the reaction proceeds, these long-chain LiPSs decompose into solid Li 2 S 2 /Li 2 S. 4 The slow conversion process between soluble long-chain LiPSs and insoluble Li 2 S 2 /Li 2 S during charge and discharge causes soluble long-chain LiPSs to dissolve in the electrolyte and then shuttle between the cathode and anode by a concentration gradient. The dissolution−deposition reaction of soluble LiPSs (Li 2 S x , 2 < x ≤ 8) is called the "shuttle effect", resulting in low Coulombic efficiency, low sulfur utilization, and poor cyclic stability.…”

“…Among them, the “shuttle effect” is considered to be one of the key problems hindering the commercialization and industrialization of Li-S batteries . Although the mechanism of the sulfur cathode REDOX reaction is still uncertain, the reduction mechanism of S 8 → Li 2 S 8 → Li 2 S 6 → Li 2 S 4 → Li 2 S 2 /Li 2 S and the reverse step in the charging process are generally accepted at present . First, solid S 8 undergoes reduction to form a series of soluble long-chain LiPSs (S 8 → Li 2 S 8 → Li 2 S 6 → Li 2 S 4 ).…”