Encapsulation of Few-Layer MoS2 in the Pores of Mesoporous Carbon Hollow Spheres for Lithium-Sulfur Batteries

Abstract

Integrating a highly conductive carbon host and polar inorganic compounds has been widely reported to improve the electrochemical performances for promising low-cost lithium sulfur batteries. Herein, a MoS2/mesoporous carbon hollow sphere (MoS2/MCHS) structure has been proposed as an efficient sulfur cathode via a simple wet impregnation method and gas phase vulcanization method. Multi-fold structural merits have been demonstrated for the MoS2/MCHS structures. On one hand, the mesoporous carbon hollow sphere (MCHS) matrix, with abundant pore structures and high specific surface areas, could load a large amount of sulfur, improve the electronical conductivity of sulfur electrodes, and suppress the volume changes during the repeated sulfur conversion processes. On the other hand, ultrathin multi-layer MoS2 nanosheets are revealed to be uniformly distributed in the mesoporous carbon hollow spheres, enhancing the physical adsorption and chemical entrapment functionalities towards the soluble polysulfide species. Having benefited from these structural advantages, the sulfur-impregnated MoS2/MCHS cathode presents remarkably improved electrochemical performances in terms of lower voltage polarization, higher reversible capacity (1094.3 mAh g−1), higher rate capability (590.2 mAh g−1 at 2 C), and better cycling stability (556 mAh g−1 after 400 cycles at 2 C) compared to the sulfur-impregnated MCHS cathode. This work offers a novel delicate design strategy for functional materials to achieve high performance lithium sulfur batteries.

Two‐Dimensional MoS2 for Li−S Batteries: Structural Design and Electronic Modulation

“…Zhao et al de-signedM oS 2 /MCHS as the sulfur cathode, which has an excellent entrapment capability and high conductivity. [56] It is also found that the integration of heteroatom-doped carbon can furtheri mprove the performance of MoS 2 for LiÀS batteries. According to DFT calculations and the results of diffusion experiments,P araknowitsch and Thomas revealed that the chemical interactions between Li 2 S x and carbon materials could be enhanced by heteroatom doping, such as N, S, and B.…”

“…Zhao et al. designed MoS 2 /MCHS as the sulfur cathode, which has an excellent entrapment capability and high conductivity …”

Application of MoS2 in the cathode of lithium sulfur batteries

“…8 Proposed adsorption mechanism of polysulfides for the (a) MCHS/S and (b) MoS 2 /MCHS/S electrodes. 35 Other researchers have also [49][50][51][52][53] devoted their attention to the application of core-shell structured MoS 2 nanocomposites. The double-layer core-shell structure has good prospects.…”

High Stable Sulfur Cathode with Self‐Healable and Physical Confining Polydimethylsiloxane Interlayer

“…Although the effectiveness of the strategies, some amount of polysulfides still dissolved in the electrolyte and thus giving rise to the performance degradation. [27][28][29][30][31][32] This means that complete inhibition of the shuttle effect remains a big challenge for LiÀ S batteries.…”

“…Through strong chemical interactions between the polar moieties and polysulfides, the shuttle effect was significantly suppressed and the resulting sulfur cathodes realized a long cycling life. Although the effectiveness of the strategies, some amount of polysulfides still dissolved in the electrolyte and thus giving rise to the performance degradation . This means that complete inhibition of the shuttle effect remains a big challenge for Li−S batteries.…”