Dual Single-Atom Moieties Anchored on N-Doped Multilayer Graphene As a Catalytic Host for Lithium–Sulfur Batteries

Abstract

Lithium−sulfur (Li−S) batteries are promising for energy storage, especially in the era of carbon neutrality. Nonetheless, the sluggish kinetics of converting soluble lithium polysulfides into solid lithium sulfide impedes its development. In this work, we design Fe and Co dual single-atom moieties anchored on N-doped multilayer graphene (FeCoNGr) as a catalytic sulfur cathode host for Li−S batteries. With an efficient catalytic role in converting soluble lithium polysulfides into solid Li 2 S, the FeCoNGr-based Li−S cell demonstrates a capacity of 878.7 mA h g −1 at 0.2 C and retains 77.4% of the initial value after 100 cycles. The first and retained capacities are ∼1.7 and ∼1.8 times those of the NGr (without single atoms)based cell, respectively. Theoretical calculations reveal that the Fe−N 4 moiety has a higher binding energy toward low-order lithium polysulfides, while the Co−N 4 moiety has a higher binding energy toward high-order lithium polysulfides. The efficient catalytic conversion of soluble lithium polysulfides into solid lithium sulfides of FeCoNGr plays important roles in outperforming NGr. This work enhances our knowledge on the tandem role of dual single-atom moieties and confirmed the high catalytic efficiency of single-atom catalysts in Li−S batteries.

Rational Design of Janus Metal Atomic‐Site Catalysts for Efficient Polysulfide Conversion and Alkali Metal Deposition: Advances and Prospects

“…Based on single-atom catalysts, considering the relatively weak interaction and the small contact area between monatomic sites and substrates, to further enhance the number and load of atomic active sites, metal diatomic sites have attracted increasing attention in recent years as emerging family members of single-atom catalysts. [90,[191][192][193] To date, the research of dual-atom catalysts remains in its infancy, the reported literatures so far mainly focused on heterogeneous diatomic catalysts and heteronuclear diatomic catalysts for M-S batteries. [88,194,195] The S-ion mappings of ToF-SIMS on the top surface of e) FeNC-EEB-1, f) FeNC-EEB-2, and g) FeNC.…”

Recent advances in modified commercial separators for lithium–sulfur batteries

“…Graphene is a 2D nanosheet of a monolayer, honeycomb-arranged carbon lattice with excellent electrical conductivity, mechanical strength, thermal stability, and high functionalizability, among other properties. 197 Graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), have many or some oxygen functionalization and are much more common in literature as they are easier to prepare while sharing similar properties with perfect graphene. 198 As modifiers for commercially available polyolefin separators, graphene and its derivatives reduce the shuttle effect via ionic sieving with controllable pore sizes and enhanced LiPS reduction kinetics owing to increased electron mobility.…”

Theoretical Calculations Facilitating Catalysis for Advanced Lithium-Sulfur Batteries

“…Because of the maximized atomic utilization and excellent catalytic activities, single atoms present accelerated conversion kinetics for sulfur cathodes. Single atoms with Fe [48], Co [86], Ni [87], Cu [88], and W [44] as active sites have been confirmed to be promising electrocatalysts, which considerably restrain the polysulfide shuttling. The coordination environment of single atoms plays a key role in catalytic activities.…”