Single-Atom Coated Separator for Robust Lithium–Sulfur Batteries

Abstract

Lithium–sulfur (Li–S) batteries are strong contenders among lithium batteries due to superior capacity and energy density, but the polysulfide shuttling effect limits the cycle life and reduces energy efficiency due to a voltage gap between charge and discharge. Here, we demonstrate that graphene foam impregnated with single-atom catalysts (SACs) can be coated on a commercial polypropylene separator to catalyze polysulfide conversion, leading to a reduced voltage gap and a much improved cycle life. Also, among Fe/Co/Ni SACs, Fe SACs may be a better option to be used in Li–S systems. By deploying SACs in the battery separator, cycling stability improves hugely, especially considering relatively high sulfur loading and ultralow SAC contents. Even at a metal loading of ∼2 μg in the whole cell, an Fe SAC-modified separator delivers superior Li–S battery performance even at high sulfur loading (891.6 mAh g–1, 83.7% retention after 750 cycles at 0.5C). Our work further enriches and expands the application of SACs catalyzing polysulfide blocking and conversion and improving round trip efficiencies in batteries, without side effects such as electrolyte and electrode decomposition.

Adsorption‐Catalysis Design in the Lithium‐Sulfur Battery

“…[95][96][97][98] Moreover, SACs achieve main strategies in electrocatalyst design: increasing the active sites and enhancing the intrinsic activity. [95][96][97][98] Moreover, SACs achieve main strategies in electrocatalyst design: increasing the active sites and enhancing the intrinsic activity.…”

“…Second, Li + decouples from the intermediate with electron withdraw in the charging process. [98] They found that the SAC-modified separator could be a bifunctional structure, which could mitigate the polysulfide shuttling effect and serve as catalyst for the redox reaction. Because of the SAFe, sulfur utilization, cycle life, and rate performance are highly enhanced.…”

Single‐Atom Catalytic Materials for Advanced Battery Systems

“…Graphene foam impregnated with single‐atom catalysts (SACMs) were coated onto a commercial polypropylene (PP) separator for application in Li–S batteries ( Figure a). [ 146 ] The preparation of Fe 1 /NG powders was similar to that illustrated in Figure 5h. [ 52 ] In order to ensure monodispersion, graphene‐ and Fe‐containing salts were added into the solution which was subsequently treated with ultrasonication to obtain Fe 1 /NG powders.…”

“…Reproduced with permission. [ 146 ] Copyright 2019, American Chemical Society. f) The free‐energy diagrams of LiPS on Ni@NG or NG.…”

A Freestanding Flexible Single‐Atom Cobalt‐Based Multifunctional Interlayer toward Reversible and Durable Lithium‐Sulfur Batteries

“…[6][7][8] Toward this end, a variety of strategies have been proposed to solve above-mentioned problems. [9][10][11][12][13][14][15] One of the common routes is to accommodate sulfur in nanostructured host materials by physical and/or chemical trap. [16][17][18][19][20] Although this strategy can enhance the electrochemical performance to some extent, the diffusion of polysulfides toward lithium anode side is inevitable in routine cell configurations.…”