Honeycomb‐like Nitrogen and Sulfur Dual‐Doped Hierarchical Porous Biomass‐Derived Carbon for Lithium–Sulfur Batteries

Abstract

Honeycomb-like nitrogen and sulfur dual-doped hierarchical porous biomass-derived carbon/sulfur composites (NSHPC/S) are successfully fabricated for high energy density lithium-sulfur batteries. The effects of nitrogen, sulfur dual-doping on the structures and properties of the NSHPC/S composites are investigated in detail by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and charge/discharge tests. The results show that N, S dual-doping not only introduces strong chemical adsorption and provides more active sites but also significantly enhances the electronic conductivity and hydrophilic properties of hierarchical porous biomass-derived carbon, thereby significantly enhancing the utilization of sulfur and immobilizing the notorious polysulfide shuttle effect. Especially, the as-synthesized NSHPC-7/S exhibits high initial discharge capacity of 1204 mA h g at 1.0 C and large reversible capacity of 952 mA h g after 300 cycles at 0.5 C with an ultralow capacity fading rate of 0.08 % per cycle even at high sulfur content (85 wt %) and high active material areal mass loading (2.8 mg cm ) for the application of high energy density Li-S batteries.

Rational Fabrication of Nitrogen and Sulfur Codoped Carbon Nanotubes/MoS2 for High‐Performance Lithium–Sulfur Batteries

“…The diffusion coefficient of Li + ‐ions in the cell system D can be deducted from Equation : …”

Stable and Fast Lithium–Sulfur Battery Achieved by Rational Design of Multifunctional Separator

“…However, despite the intrinsic low electronic conductivity of S cathode, the critical issue of Li‐S battery is the dissolution of polysulfides in the electrolyte, so‐called “shuttle effect,” which causes low Coulombic efficiency, capacity fading, Li corrosion, and self‐discharging . To address challenging issues, rational designs of the electrode are examined in the Li‐S battery system, including 1) impregnation of sulfur inside the hierarchical structural carbon hosts (i.e., graphene, carbon nanotube, carbon nanofiber, and meso/microporous carbon), 2) warping of the sulfur with compact shell materials (hollow carbon sphere, functional polymers), and 3) capturing of sulfur species with the polarity materials (e.g., metal, metal oxides, transition metal sulfide, covalent organic frameworks (COFs), heteroatom‐doped carbon, MXene,). Additionally, well‐designed chemical‐confinement strategies (i.e., introduction of sulfur in polysulfides polymer) are adopted to improve the cycling stability of Li‐S cells.…”

A Porous Carbon Polyhedron/Carbon Nanotube Based Hybrid Material as Multifunctional Sulfur Host for High‐Performance Lithium‐Sulfur Batteries

“…Nevertheless, the weak interactions between nonpolar carbon materials and polar sulfur species are insufficient to restrain polysulfides diffusion and shuttle over long‐term cycling, unavoidably resulting in serious capacity fading . Recently, it has been proved that the nonmetal heteroatoms functionalized carbon materials can significantly increase the immobilization of polysulfides due to the formation of some chemical bonds . Apart from doped carbon matrix, some polar transition metal materials including Fe, Co and Ni, and their metal oxides, sulfides and nitrides have also received great attention.…”