Journal Article

Breaking Barriers to High‐Practical Li‐S Batteries with Isotropic Binary Sulfiphilic Electrocatalyst: Creating a Virtuous Cycle for Favorable Polysulfides Redox Environments

Kim, Jong‐Hoon, Xiao, Wei, Xu, Hengyue, Yoo, Kisoo

2023

Overview

Investigations into lithium–sulfur batteries (LSBs) has focused primarily on the initial conversion of lithium polysulfides (LiPSs) to Li2S2. However, the subsequent solid–solid reaction from Li2S2 to Li2S and the Li2S 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 Ni3B in synergy with carbon nanotubes (aNi3B@CNTs) is proposed to implement the consecutive catalysis of S8(solid) → LiPSs(liquid) → Li2S(solid) →LiPSs(liquid). Systematic theoretical simulations and experimental analyses reveal that aNi3B@CNTs with an isotropic structure and abundant active sites can ensure rapid LiPSs adsorption‐catalysis as well as uniform Li2S precipitation. The uniform Li2S deposition in synergy with catalysis of aNi3B enables instant/complete oxidation of Li2S 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 aNi3B@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. Virtuous cycle for consecutive electrocatalysis. Specifically, the binary sulfiphilic aNi3B with isotropic structure enables a rapid/uniform LiPSs adsorption. Meanwhile, the superior catalytic capability and ionic/electronic conductivity synergistically facilitated the fast/homogeneous Li2S precipitation. Uniform Li2S deposition helps fully oxidize it to LiPSs, which are quickly and uniformly adsorbed for the next sulfur evolution, creating a virtuous cycle for sulfur species conversion.

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Adsorption / binary sulfiphilic catalyst / Catalysis / Electrolytes / Fourier transforms / isotropic adsorption‐catalysis / Lithium / Nanoparticles / practical Li–S batteries / Scanning electron microscopy / Sulfur / virtuous cycle / wide‐temperature range application