Metal–Organic Frameworks Reinforce the Carbon Nanotube Sponge-Derived Robust Three-Dimensional Sulfur Host for Lithium–Sulfur Batteries

Abstract

Sulfur is a prospective material for next-generation batteries with high theoretical capacity, but its drawbacks hinder its commercialization. To overcome the low conductivity of natural sulfur and the shuttle effect of lithium polysulfide, the study proposes a novel sulfur film coated with three-dimensional nitrogen and cobalt-codoped polyhedral carbon wrapped on a multiwalled carbon nanotube sponge (3D-S@NCoCPC sponge) composite as a high-performance cathode material for rechargeable lithium–sulfur batteries. The interconnected conductive carbon network with abundant pores provides more room for the homogeneous distribution of sulfur within the composite and creates a favorable pathway for electrolyte permeability and lithium-ion diffusion. Moreover, the strong interaction between cobalt and lithium polysulfides leads to efficient suppression of the shuttle effect. In addition, the homogeneous distribution of sulfur and cobalt within the composite enhances electronic transfer for the conversion reaction of sulfur. As expected, the cathode with a high sulfur content of 77.5 wt % in the composite achieved a high initial discharge capacity of 1192 mA h g–1 and high Coulombic efficiency of 99.98% after 100 cycles at 100 mA g–1 current density. Stable performance was achieved with 92.9% capacity retention after 200 cycles at 1000 mA/g current density.

1D confined materials synthesized via a coating method for thermal catalysis and energy storage applications

“…Li-S-Bs are promising alternatives for nextgeneration rechargeable batteries because of their low cost and high theoretical energy density (2600 W h kg À1 ). [174][175][176] However, problems such as the low conductivity of S and Li 2 S, and the shuttle effect which means the loss of S as a result of their dissolution and migration in ether-based electrolyte, as well as the large volume changes lead to low reversible capacity and short cycling life, which need to be solved before their practical application. 59,177,178 Designing 1D conned electrode materials within a carbon layer can be one of the most effective strategies to combat these problems.…”

3D Carbon Materials for High-Performance Electric Energy Storage Facilities

“…The CCCs were applied for the cathode for three reasons: the advanced pore structure of the framework can adsorb and preserve the soluble intermediate LiPSs; the large vacant space help accommodate the volume change during electrochemical reaction; the large SSA and the ideal conductivity are benefits for shortening the electron-transfer path and improving the electrical contact between sulfur and the current collector, thus accelerating the reaction rate. Therefore, in an earlier study, researchers concentrated on optimizing the porous structure and enlarging the electrochemically active area of the CCCs. − Based on such a principle, a series of porous carbon materials were experimented with, for instance, CNT arrays or networks, carbon sponge, GO frameworks, and so on. − Our group has also designed a special carbon framework for the sulfur cathode, which was prepared by two steps: step one, carbon foam composed of ultrathin graphitic tubes (UGF) connected by covalent bonds was fabricated by CVD; step two, ordered CNT arrays with a length of millimeters were grown throughout the microsurface of the carbon foam, with the CNT fibers rooted tightly onto the graphitic tubes by covalent bonds (Figure a–d) . Therefore, the CNT-UGF depicted a hierarchically porous structure, which was different from the classical CCC designs.…”

Recent Development in Novel Lithium-Sulfur Nanofiber Separators: A Review of the Latest Fabrication and Performance Optimizations

“…One of the most promising next-generation batteries is the lithium-sulfur battery (LSB) because of its high theoretical capacity, natural abundance, and safety. LSBs have theoretical energy densities that are five times higher than Li-ion batteries, boasting a theoretical energy density of 2500 Wh kg −1 and a specific capacity of 1672 mAh g −1 [ 12 ]. However, LSBs are not yet ready for commercial adoption because of their poor cyclability and rate capability, which stem from address Li polysulfide (LiPS) shuttling (discussed in Section 2 ), Li dendrite formation, and the low conductivity of sulfur [ 13 , 14 ].…”