Sulfide with Oxygen-Rich Carbon Network for Good Lithium-Storage Kinetics

Abstract

Transition metal sulfides are of great interest as electrode material for alkali metal-ion batteries due to their high theoretical capacity. However, sluggish ion migration and electron transfer kinetics lead to poor cycling stability and rate performance, which hinders their practical applications. Herein, we develop a two-step localized carbonization and sulfurization method to construct a CoS2 composite material (CoS2@CNTs@C) from an in situ integrated zeolitic imidazolate framework (ZIF-67) and multiwalled carbon nanotube precursor (ZIF-67@CNTs). The as-prepared CoS2@CNTs@C composites with a nanoscale carbon skeleton inherit a large specific surface area and suitable nanopore size distribution from ZIF-67 and incredibly abundant oxygenated functional groups from CNTs. The theoretical calculation and material characterization demonstrate that the oxygenated functional groups on the porous carbon networks accelerate lithium-ion diffusion and electron transfer and especially electrocatalyze the progressive conversion of Li2S6 to the final product Li2S. Meanwhile, the three-dimensional conductive network guarantees the conductive and structural stability of CoS2@CNTs@C during the repeated lithium-storage process. Therefore, the CoS2@CNTs@C electrode material can deliver an initial discharge capacity of 1282.3 mA h g–1 at 200 mA g–1 with a high Coulombic efficiency of 93.5% and a reversible capacity of 558.8 mA h g–1 at 2000 mA g–1 in 600 cycles with a high capacity retention of 96.1%.

Heterostructure CoS2/MoS2 Nanosheets as a Dual-Active Electrocatalyst for the Oxygen Evolution Reaction

“…Two broad diffraction peaks at 26.1° and 44.4° in CC, CC@ZIF-67, and CC@CoS 2 /MoS 2 were assigned to the (002) and (100) reflections of graphite, respectively (JCPDS 41–1487) . After the sulfurization process, the typical peaks of ZIF-67 vanished from the sample of CC@ZIF-67 with the emergence of a series of peaks located at 14.4° and 32.3°, 36.2°, 39.8°, and 54.9°, respectively corresponding to the MoS 2 (JCPDS 37–1492) and CoS 2 (JCPDS 41–1471), , suggesting the successful synthesis of the heterojunction CC@CoS 2 /MoS 2 (Figure a). The composition of the C, S, Co, and Mo elements was confirmed by using X-ray photoelectron spectroscopy (XPS), which was used to observe the surface elemental component and the chemical state of elements for CC@CoS 2 /MoS 2 (Figure b).…”

Metal–organic frameworks and their derivatives for metal-ion (Li, Na, K and Zn) hybrid capacitors

“…Oxygen functional groups can provide opportunities to further improve the electrochemical performance, and abundant oxygen functional groups can provide additional capacitive adsorption sites for metal ions, which can significantly increase the capacity. [175][176][177][178] Lu's research group proposed that the C-O bond participates in the Zn storage process by forming C-O-Zn with Zn 2+ , while the additional N doping can significantly promote the chemisorption of Zn 2+ . 179 Shao et al demonstrated that carboxyl and carbonyl groups can significantly improve Zn 2+ chemisorption, pseudocapacitive redox activity, and aqueous electrolyte wettability.…”

Metal–Organic Framework–Based CoS2 Nitrogen‐Doped Carbon for High‐Performance Lithium Storage

“…However, CoS 2 electrode is suffering from the volume expansion and pulverization during work, resulting in poor cycle and rate performance, which hinder its widespread application. [6][7][8][9] Recently, significant attempts have been made to overcome the issues. As reported, carbonbased compounds could ensure the LIBs working better by reducing volume expansion during the cycle process and promoting rapid electron transfer.…”