Breaking Barriers to High-Practical Li-S Batteries with Isotropic Binary Sulfiphilic Electrocatalyst: Creating a...

Investigations into lithium-sulfur batteries (LSBs) has focused primarily on the initial conversion of lithium polysulfides (LiPSs) to Li₂ S₂ . However, the subsequent solid-solid reaction from Li₂ S₂ to Li₂ S and the Li₂ S decomposition process should be equally prioritized. Creating a virtuous cycle by balancing all three chemical reaction processes is crucial for realizing practical LSBs. Herein, amorphous Ni₃ B in synergy with carbon nanotubes (aNi₃ B@CNTs) is proposed to implement the consecutive catalysis of S_8(solid) → LiPSs_(liquid) → Li₂ S_(solid) →LiPSs_(liquid) . Systematic theoretical simulations and experimental analyses reveal that aNi₃ B@CNTs with an isotropic structure and abundant active sites can ensure rapid LiPSs adsorption-catalysis as well as uniform Li₂ S precipitation. The uniform Li₂ S deposition in synergy with catalysis of aNi₃ B enables instant/complete oxidation of Li₂ S to LiPSs. The produced LiPSs are again rapidly and uniformly adsorbed for the next sulfur evolution process, thus creating a virtuous cycle for sulfur species conversion. Accordingly, the aNi₃ B@CNTs-based cell presents remarkable rate capability, long-term cycle life, and superior cyclic stability, even under high sulfur loading and extreme temperature environments. This study proposes the significance of creating a virtuous cycle for sulfur species conversion to realize practical LSBs.