Multisize CoS₂ Particles Intercalated/Coated‐Montmorillonite as Efficient Sulfur Host for High‐Performance Lithium‐Sulfur Batteries

Abstract

The chemisorption and catalysis of lithium polysulfides (LiPSs) are effective strategies to suppress the shuttle effect in lithiumsulfur (LiÀ S) batteries. Herein, multisize CoS 2 particles intercalated/coated-montmorillonite (MMT) as an efficient sulfur host is synthesized. As expected, the obtained S/CoS 2 @MMT cathode achieves an absorption-catalysis synergistic effect through the polar MMT aluminosilicate sheets and the well-dispersed nanomicron CoS 2 particles. Furthermore, efficient interlamellar ion pathways and interconnected conductive network are con-structed within the composite host due to the intercalation/ coating of CoS 2 in/on MMT. Therefore, the S/CoS 2 @MMT cathode achieves an outstanding rate performance up to 5C (5 48 mAh g À 1 ) and a high cycling stability with low capacity decay of 0.063 and 0.067 % per cycle for 500 cycles at 1C and 2C, respectively. With a higher sulfur loading of 4.0 mg cm À 2 , the cathode still delivers satisfactory rate and cycling performance. It shows that the CoS 2 @MMT host has great application prospects in LiÀ S batteries.

CoS2@montmorillonite as an efficient separator coating for high-performance lithium–sulfur batteries

“…The CoS 2 @montmorillonite composite was synthesized according to our previous work. 34 Firstly, a general cation exchange process was performed to replace the interlaminar cations (i.e., Mg 2+ , Ca 2+ , Na + ) of montmorillonite by Co 2+ . Subsequently, a facile hydrothermal method was adopted for the grain growth of CoS 2 , during which the CoS 2 particles were simultaneously synthesized on the surfaces and in the interlayers of montmorillonite.…”

“…The morphology and structure of the CoS 2 @montmorillonite composite have been thoroughly studied in our previous work and it was reported that the montmorillonite matrix possesses a 2D layered structure with a large basal spacing of 1.94 nm, and the CoS 2 microcrystals ( particle size ∼200 nm) and ultrafine nanoparticles ( particle size ∼5 nm) are embedded and distributed uniformly on the surface and in the interlayers of the montmorillonite matrix, respectively. 34 transformation (FFT) images (Fig. S2b and d †) reveal that the lattice distances of the CoS 2 microcrystals and nanoparticles are 0.320 and 0.226 nm based on calculations, which are indexed to the (111) and (211) planes of CoS 2 , respectively.…”

“…The CoS 2 @montmorillonite composite was synthesized according to our previous work. 34 Firstly, a general cation exchange process was performed to replace the interlaminar cations ( i.e. , Mg 2+ , Ca 2+ , Na + ) of montmorillonite by Co 2+ .…”

“…The CoS 2 @montmorillonite composites were synthesized according to the method described in our previous work. 34 Typically, 10 mmol of Co(NO 3 ) 2 ·6H 2 O and 1 g of montmorillonite were added to 100 mL of deionized water and then vigorously stirred at 60 °C for 3 h. Subsequently, 20 mmol of Na 2 S 2 O 3 ·5H 2 O was dissolved in the above suspension, then the obtained mixture was transferred to a 150 mL Teflon autoclave and maintained at 180 °C for 24 h. Finally, the CoS 2 @montmorillonite composite was obtained after washing and drying treatments.…”

“…23,24 Recently, many reports have demonstrated that the unique atomic interlamellar ion path structure of montmorillonite can be used to construct efficient Li ion transport pathways/channels in separators and sulfur cathodes, thus promoting Li ion transport and restraining the growth of lithium dendrites. 28,31–33 On the basis of the above findings, our previous work 34,35 endowed the montmorillonite matrix with high conductivity through the intercalation and coating of conductive materials in the interlayers and on the surface of montmorillonite. The obtained montmorillonite-based materials were used as sulfur hosts which not only possess fast Li ion transport pathways and efficient conductive networks, but also have strong chemisorption of polysulfides and high catalytic activity for polysulfide redox reactions.…”