Realizing Li−S Batteries with Efficient Polysulfide Trapping and Conversion by using a High‐Nitrogen‐Content‐Doped Fe−N−C Porous Carbon Nanosheet‐Modified Separator

Abstract

Lithium-sulfur (LiÀ S) batteries with high theoretical energy density have earned much attention in recent years. Nevertheless, the shuttle effect and tardy conversion of polysulfides severely hinder their practical applications. Herein, the highnitrogen-doped FeÀ NÀ C porous carbon nanosheets (denoted as ATÀ FeÀ NÀ CÀ Me) were synthesized and coated on separator as an effective electrocatalyst for LiÀ S batteries. Benefiting from the hierarchical porous carbon structure and rich FeÀ N x catalytic sites, the ATÀ FeÀ NÀ CÀ Me coating layer can effectively suppress the polysulfides shuttling and promote their redox conversion simultaneously. As a result, the LiÀ S batteries with ATÀ FeÀ NÀ CÀ Me modified separators deliver superior rate capability (785.5 mAh g À 1 at 4.0 C) and cycling stability (capacity decay rate of 0.065 % per cycle over 1000 cycles at 1.0 C). This work provides a new strategy to design efficient electrocatalyst with high-surface-area porous structure for high-performance LiÀ S batteries.

Nickel–Nitrogen–Carbon Nanoparticles as Polysulfide Adjustment Layers for Lithium–Sulfur Batteries

“…Benefiting from the high conductivity of Fe–N–C and its robust chemical adsorption capacity for LPS, the porous interlayer structure of the modified layer demonstrates excellent capability in inhibiting the LPSs shuttle . Fe–N–C materials are also utilized for oxidation–reduction catalysis in proton exchange membrane fuel cells and as modifiers in Li–S battery separators. , In high-energy Li–S pouch cells, Cao et al developed an integrated “nitrogen balance” approach to create a highly active Ni–N–C system by controlling localized nitrogen release. This approach optimizes the Ni atom loading, Ni coordination configuration, active nitrogen sites, N vacancy defects, and electronic conductivity, thereby enhancing the activity of the Ni–N–C system significantly .…”

Recent advances in modified commercial separators for lithium–sulfur batteries

“…The separator is a critical component in modern batteries that act as a physical barrier between the cathode and anode, preventing short-circuiting while allowing fast ion diffusion via the permeating electrolyte. 88 The most widely available separators are microporous polyolefin-based membranes often used in LIBs, which are fabricated from polypropylene (PP), polyethylene (PE), or a blend of both. These separators are sold commercially under brand names like Celgard.…”