Delocalized Isoelectronic Heterostructured FeCoO_xS_y Catalysts with Tunable Electron Density for Accelerated Sulfur Redox Kinetics in Li‐S batteries

Abstract

High interconversion energy barriers, depressive reaction kinetics of sulfur species, and sluggish Li+ transport inhibit the wide development of high‐energy‐density lithium sulfur (Li‐S) batteries. Herein, differing from random mixture of selected catalysts, the composite catalyst with outer delocalized isoelectronic heterostructure (DIHC) is proposed and optimized, enhancing the catalytic efficiency for decreasing related energy barriers. As a proof‐of‐content, the FeCoOxSy composites with different degrees of sulfurization are fabricated by regulating atoms ratio between O and S. The relationship of catalytic efficiency and principal mechanism in DIHCs are deeply understood from electrochemical experiments to in‐situ/operando spectral spectroscopies i.e., Raman, XRD and UV‐Vis. Consequently, the polysulfide conversion and Li2S precipitation/dissolution experiments strongly demonstrate the volcano‐like catalytic efficiency of various DIHCs. Furthermore, the FeCoOxSy‐decorated cell delivers the high performance (1413 mAh g‐1 at 0.1 A g‐1). Under the low electrolyte/sulfur ratio, the high loading cell stabilizes the areal capacity of 6.67 mAh cm‐2 at 0.2 A g‐1. Impressively, even resting for about 17 days for possible polysulfide shuttling, the high‐mass‐loading FeCoOxSy‐decorated cell stabilizes the same capacity, showing the practical application of the DIHCs in improving catalytic efficiency and reaching high electrochemical performance.

Versatile Composite Binder with Fast Lithium-Ion Transport for LiCoO2 Cathodes

“…Lithium-ion batteries (LIBs) are widely used in portable electronics, electric vehicles, and other energy storage devices due to their high energy density, long cycle life, and good safety. − Among numerous cathode materials for LIBs, LiCoO 2 stands out because of the high volumetric energy density and compaction density and stable charge–discharge voltage. − However, there are also some problems with LiCoO 2 cathodes that limit the application. For example, the low ionic conductivity of LiCoO 2 results in slow transportation of Li + in the bulk phase of the LiCoO 2 material.…”

Promoting overall sulfur redox kinetics for Li–S batteries via interfacial synergy in a NiS–NiTe2 heterostructure-modified separator

“…Although the separator is not an active component within the battery, its role in influencing crucial aspects such as cost, cycle life, and safety cannot be overstated. 18–21 The pores in the separator allow lithium ions to conduct between the anode and the cathode during the charge and discharge cycles, facilitating stable electrochemical reactions. Moreover, the separator serves a dual purpose by providing a physical barrier, preventing internal short circuits.…”

Design of WO2.83-WN Heterostructure Bidirectional Catalyst for High-Performance Lithium–Sulfur Batteries

“…This binary host combines the advantages of the highly adsorptive VO 2 and the highly conductive VN, achieving both high anchoring efficiency and rapid conversion of LiPSs simultaneously. Chen et al 12 constructed a delocalized isoelectronic heterojunction catalyst by substituting sulfur for oxygen in iron cobalt oxide to create more catalytic sites at the heterojunction interface. This improves the sulfur reaction kinetics and Li−S battery performance.…”