A Combined Ordered Macro‐Mesoporous Architecture Design and Surface Engineering Strategy for High‐Performance Sulfur Immobilizer in Lithium–Sulfur Batteries

Abstract

The practical application of lithium–sulfur (Li–S) batteries is hindered by the “shuttle” of lithium polysulfides (LiPS) and sluggish Li–S kinetics issues. Herein, a synergistic strategy combining mesoporous architecture design and defect engineering is proposed to synthesize multifunctional defective 3D ordered mesoporous cobalt sulfide (3DOM N‐Co9S8−x) to address the shuttling and sluggish reaction kinetics of polysulfide in Li–S batteries. The unique 3DOM design provides abundant voids for sulfur storage and enlarged active interfaces that reduce electron/ion diffusion pathways. Meanwhile, X‐ray absorption spectroscopy shows that the surface defect engineering tunes the CoS4 tetrahedra to CoS6 octahedra on Co9S8, endowing abundance of S vacancies on the Co9S8 octahedral sites. The ever‐increasing S vacancies over the course of electrochemical process further promotes the chemical trapping of LiPS and its conversion kinetics, rendering fast and durable Li–S chemistry. Benefiting from these features, the as‐developed 3DOM N‐Co9S8−x/S cathode delivers high areal capacity, superb rate capability, and excellent cyclic stability with ultralow capacity fading rate under raised sulfur loading and low electrolyte content. This design strategy promotes the development of practically viable Li–S batteries and sheds lights on the material engineering in related energy storage application.

Manipulating the Conversion Kinetics of Polysulfides by Engineering Oxygen p‐Band of Halloysite for Improved Li‐S Batteries

“…The efficient catalysis effect of SC‐TiO 2 ‐Hal enables the Li‐S battery to deliver the highest discharge capacity of 1037.6 mAh g −1 at 0.2 C compared with SC‐TiO 2 /S (793.1 mAh g −1 ) and SC‐Hal/S (629.9 mAh g −1 ), and the reversible capacity of 566.9 mAh g −1 at 5 C. Especially for SC‐Hal/S, decreased sharply between 0.2 and 0.5 C, which might be due to the low electrical conductivity (Figure S19, Supporting Information), leading to the poor rate capabilities. [ 26 ] In comparison, SC‐TiO 2 /S and SC‐Hal/S can only reach the discharge capacity of 317.0 and 94.3 mAh g −1 at 5 C, respectively. When the current shifts back to 0.2 C, the discharge capacity of SC‐TiO 2 ‐Hal/S is rapidly recuperative compared with SC‐TiO 2 /S and SC‐Hal/S, implying that downshift O p‐band center can accelerate catalytic conversion kinetics for LiPSs.…”

Defect Engineering for Expediting Li–S Chemistry: Strategies, Mechanisms, and Perspectives

“…[104][105][106] Recently, vacancy engineering has stimulated an immerse interest in boosting the chemical entrapment and catalytic conversion of PS in Li-S system. [107][108][109][110] In this section, the fabrication and characterization of vacancy are introduced, followed by the discussion on the essential role of vacancy played in accelerating Li-S chemistry from experimental analysis and theoretical simulation. The optimized electronic structure via vacancy engineering is also covered to better understand the sulfur redox chemistry at an atomic scale.…”

Designing principles of advanced sulfur cathodes toward practical lithium‐sulfur batteries

“…In addition, mesopore can also strongly inhibit the LiPSs shuttle via physical confinement at the cost of decreased sulfur loading compared to macropore. Various mesoporous carbon 68,70 /metal-based 69 hosts alongside a tailored degree of pore ordering 71,72 were synthesized by different methods (hard/soft template), and the resultant composite cathodes demonstrated significant performance improvements.…”