Coordinated Adsorption and Catalytic Conversion of Polysulfides Enabled by Perovskite Bimetallic Hydroxide Nanocages for Lithium‐Sulfur Batteries

Abstract

Catalysis is an effective remedy for the fast capacity decay of lithium‐sulfur batteries induced by the shuttling of lithium polysulfides (LiPSs), but too strong adsorption ability of many catalysts toward LiPSs increases the risk of catalyst passivation and restricts the diffusion of LiPSs for conversion. Herein, perovskite bimetallic hydroxide (CoSn(OH)6) nanocages are prepared, which are further wrapped by reduced graphene oxide (rGO) as the catalytic host for sulfur. Because of the coordinated valence state of Co and Sn and the intrinsic defect of the perovskite structure, such bimetallic hydroxide delivers moderate adsorption ability and enhanced catalytic activity toward LiPS conversion. Coupled with the hollow structure and the wrapped rGO as double physical barriers, the redox reaction kinetics, and sulfur utilization are effectively improved with such a host. The assembled battery delivers a good rate performance with a high capacity of 644 mAh g−1 at 2 C and long stability with a capacity decay of 0.068% per cycle over 600 cycles at 1 C. Even with a higher sulfur loading of 3.2 mg cm−2 and a low electrolyte/sulfur ratio of 5 µL mg−1, the battery still shows high sulfur utilization and good cycling stability.

In situ tailored strategy to remove capping agents from copper sulfide for building better lithium–sulfur batteries

“…4g), where the lower Tafel slope could indicate faster charge transfer kinetics without long-chain oleylamine on the surface. 37 The electrochemical impedance spectroscopy Nyquist plots can accurately explain the internal electrochemical characteristics of the symmetric cells (Fig. S3d†).…”

Phosphorization-Introduced Defect-Rich Phosphorus-Doped Co3O4 with Propelling Adsorption–Catalysis Transformation of Polysulfide

“…On the basis of the physical constraint effect of porous carbon matrices for sulfur confinement, − transition-metal-based polar catalysts with a strong chemical binding force and electrocatalytic activity toward lithium polysulfides were implanted in a carbonaceous support to form a hybrid electrocatalyst to realize multiple efficient trappings. − The use of a carbonaceous support not only affords a conductive network for the electrocatalysts but also is beneficial for reducing their size to expose more catalytic active sites. Recently, the surface defect engineering of electrocatalysts has been enthusiastically employed to optimize the surface/interface catalysis performance to endow efficient catalytic conversion and prevent capacity fading. − Two main defects, heteroatom and intrinsic defects, can change the local electronic structure, adjust the electrical conductivity, and further regulate the chemical properties of active sites . Usually, the generation of a heteroatom defect from cation doping or anion doping concomitantly induces the appearance of intrinsic defects including lattice distortion, atom vacancy, and atom dislocation .…”

“…22−24 Two main defects, heteroatom and intrinsic defects, can change the local electronic structure, adjust the electrical conductivity, and further regulate the chemical properties of active sites. 25 Usually, the generation of a heteroatom defect from cation doping or anion doping concomitantly induces the appearance of intrinsic defects including lattice distortion, atom vacancy, and atom dislocation. 26 Under the synergistic effect of heteroatom and intrinsic defects, the cathodic electrocatalysts in Li−S batteries express an exceedingly bidirectional catalytic effect, in contrast with those with a single defect.…”

Cu–Mo Bimetal Modulated Multifunctional Carbon Nanofibers Promoting the Polysulfides Conversion for High-Sulfur-Loading Lithium–Sulfur Batteries

“…In recent years, various composites with electrocatalytic properties have been widely applied as a host material for sulfur cathodes. − Electrocatalysts could accelerate the redox kinetics of Li–S batteries by catalytically boosting the conversion of LiPS, leading to improved sulfur utilization and a significant increase in cell capacity, which is an effective way to inhibit the shuttle effect and achieve high sulfur utilization for high-sulfur-loading freestanding cathodes. ,− Among reported electrocatalysts, bimetal-based catalysts have been found to be promising LiPS electrocatalyst because of their function to chemically interact with LiPS and boost the kinetic conversion of LiPS . The composites with a synergistic effect of binary metal nanoparticles generally exhibit enhanced catalytic performance over traditional monometallic ones. , Furthermore, electron transfer between different metals can modulate the electron density distribution between them, allowing bimetallic catalysts to have adjustable adsorption and catalytic performance .…”