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

Abstract

The development of Li‐S batteries is greatly hindered by the polysulfide shuttling and sluggish sulfur redox kinetics, leading to low utilization of active materials and rapid capacity decay. Herein, a freestanding multifunctional interlayer, prepared by layer‐by‐layer assembling of the single‐atom cobalt‐anchored nitrogen‐doped carbon nanosheets (NC@SA‐Co) and dual network of carbon nanotube‐cellulose nanofiber (CNT‐CNF) hybrid, is proposed to effectively enhance the polysulfide immobilization and sulfur redox kinetics. The conductive CNT network acts as the physical barrier to confine the polysulfide diffusion and to facilitate the reuse of polysulfides. The oxygen‐group‐terminated CNF network allows the hopping of Li+ ion and suppresses the polysulfide crossover due to the strong electrostatic repulsion. Moreover, it is demonstrated that the 2D NC@SA‐Co with numerous well‐defined single sites of Co–N4 can effectively serve as an electrocatalyst to boost the reversible reaction of polysulfides. As a result, the assembled Li‐S batteries with the multifunctional interlayer deliver a high reversible specific capacity of 1160 mAh g−1 at 0.1 C and an ultralow capacity decay of 0.058% per cycle over 700 cycles. Even with a high sulfur loading of 7.2 mg cm−2, a high areal capacity of 8.3 mAh cm−2 can be achieved.

Single-atom catalysts for metal-sulfur batteries: Current progress and future perspectives

“…The Li-S battery showed long-term cycling performance that retained 83.7% capacity (892 mAh/g) after 750 cycles at 0.5C, at 4.5 mg cm À2 of sulfur loading. Guo et al designed a freestanding and flexible multifunctional interlayer by assembling the 2D ultrathin SA-Co@NC and carbon nanotube-cellulose nanofiber (CNT-CNF) hybrid network to enhance the confinement and redox reaction of polysulfides [127]. Li-S batteries with the SA-Co@NC modified interlayer delivered an ultralow capacity decay of 0.058% per cycle over 700 cycles at 2C.…”

Advanced energy materials for flexible batteries in energy storage: A review

“…[51][52][53][54][55][56] Lithium-sulfur/oxygen (Li-S/O 2 ) batteries exhibit overwhelming energy density than conventional lithium/ sodium-ion (Li/Na-ion) batteries. [57][58][59][60][61][62][63][64][65] A technical leap in the lithium metal anode has a promise to significantly increase energy density. [66][67][68][69][70][71][72][73] Zinc-based batteries with high safety and power density also gain growing attention in flexible batteries.…”

Metal Atom-Decorated Carbon Nanomaterials for Enhancing Li-S/Se Batteries Performances: A Mini Review

“…In addition, a combination of metal atoms and metal compounds to modify the carbon materials is another strategy to construct an effective catalyst and anchor substrate for LiPS (Li et al, 2019b;Li et al, 2020c;Tan et al, 2020). For example, Yuan et al reported nitrogen-doped graphene nanoribbons@Co/CoOOH as an integrated sulfur host as shown in Figure 3G (Tan et al, 2020).…”