A Honeycomb-like Co@N–C Composite for Ultrahigh Sulfur Loading Li–S Batteries

Abstract

Because of the high theoretical capacity of 1675 mAh g and high energy density of 2600 Wh kg, respectively, lithium-sulfur batteries are attracting intense interest. However, it remains an enormous challenge to realize high utilizations and loadings of sulfur in cathodes for the practical applications of Li-S batteries. Herein, we design a quasi-2D Co@N-C composite with honeycomb architecture as a multifunctional sulfur host via a simple sacrificial templates method. The cellular flake with large surface area and honeycomb architecture can encapsulate much more sulfur, leading to high sulfur content (HSC) composites, and by stacking these HSC flakes, a high sulfur loading (HSL) electrode can be realized due to their high layer bulk density. Compared to our previous work in multifunctional Co-N-C composites, the cellular Co@N-C composite displays a distinct enhancement in the sulfur content, sulfur loading, cycle stability, and rate performance. Benefiting from the cellular morphology, a composite with an HSC of 93.6 wt % and an electrode with an HSL of 7.5 mg cm can be obtained simultaneously, which exhibited excellent rate performance up to 10 C (3.6 mg cm) and great cycling stability.

Separator Modified by Cobalt‐Embedded Carbon Nanosheets Enabling Chemisorption and Catalytic Effects of Polysulfides for High‐Energy‐Density Lithium‐Sulfur Batteries

“…Brunauer-Emmett-Teller-specific surface area and total pore volume are 213 m 2 g −1 and 0.598 m 3 g −1 , respectively. [35] The high-resolution N 1s XPS spectrum shows the presence of pyridinic-N (398.3 eV, 41.3%), Co-N (399.0 eV, 22.9%), pyrrolic-N (400.1 eV, 28.1%), and graphitic-N (401.1 eV, 7.7%) species (Figure 3e). The electrical conductivity of 1.96 × 10 3 S m −1 is higher than those in the reported heteroatom-doped carbon materials.…”

“…The electrical conductivity of Co-N x @NPC/G was measured using a linear four-point probe resistivity measurement system. [30,35] Obviously, the pyridinic and pyrrolic nitrogen atoms are predominant; they can serve as favorable chemisorption sites for polysulfides. [33,34] The surface chemical compositions and bonding configurations of Co-N x @NPC/G were investigated by X-ray photoelectron spectroscopy (XPS) analyses.…”

Review of Carbon Materials for Lithium‐Sulfur Batteries

“…Jin and their group [147] obtained the boron and oxygen dually doped multi-walled carbon nanotubes (BO-MWCNTs) composite, and selected MWCNTs as sulfur accommodation and B 2 O 3 as the source of boron and oxygen. The schematic illustration of the fabrication process of BO-MWNTs based on the solid-state reaction method is displayed in Figure 15.…”

“…Schematic illustration of the fabrication process of BO-MWNTs based on the solid-state reaction method. [147] Figure 16. Schematic illustration of trapping lithium polysulfides by the CNTOH-coated separator.…”

Effect of graphene oxide size and structure on synthesis and optoelectronic properties of hybrid graphene oxide‐poly(3‐hexylthiophene) nanocomposites

“…In addition, the band gap of polythiophene derivatives can be modulated through molecular design to make a polymer whose absorption matches with the maximum photon flux of the solar spectrum and to improve the photoresponse voltage [12,13]. Graphene is the thinnest twodimensional nanomaterial that can be fabricated into various forms, from quantum dots to composite materials [11,[14][15][16][17][18][19]. Graphene-based materials have been studied as significant building blocks for future nanodevices owing to their superior characteristics [20][21][22][23][24][25][26].…”