CoS₂ Hollow Spheres: Fabrication and Their Application in Lithium-Ion Batteries

Abstract

Uniform hollow spheres of CoS2 have been successfully synthesized via a facile solvothermal method and electrochemically investigated as anode material for lithium-ion batteries. The key strategy is that sulfur powder is used as the sulfur source, while absolute ethanol (EtOH) serves as the solvent and reducing agent simultaneously. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) patterns demonstrate the high purity of the product. SEM images display that the hollow spheres are about 2−3 μm in diameter and 300 nm in shell thickness. The mechanism for the formation of the final hollow structure is discussed. Temperature and reaction concentrations are found to be the key factors in controlling the morphologies. Meanwhile, electrochemical measurements reveal that the as-prepared CoS2 delivers high discharge capacity (1210 mAh g−1) and good cycle stability, indicating that it might find possible application as anode material for lithium-ion batteries in the long term.

Multifunctional Co3S4/Graphene Composites for Lithium Ion Batteries and Oxygen Reduction Reaction

“…This obvious capacity fading in the initial cycles is a result of many complicated side-reactions and the irreversible insertion of Li + into the composites as well as the formation of the SEI. [23] In comparison, Co 3 S 4 showed discharge and charge capacities of 1134 and 770 mA h g À1 , respectively ( Figure S6a in the Supporting Information). Continuous fading in the capacity was observed with increasing number of cycles, as shown in Figure 2b.…”

“…These cobalt sulfides have shown great potential for use in LIBs, [18,[23][24][25] semiconductors, [26] magnets, catalysts, [12,13,[27][28][29][30] and photocatalytic degradation. [32] The thermal stability and electrical conductivity of cobalt sulfides are much better than those of other metal sulfides, [23] however, they have a number of major drawbacks, namely Abstract: Cobalt sulfide is a good candidate for both lithium ion batteries (LIBs) and cathodic oxygen reduction reaction (ORR), but low conductivity, poor cyclability, capacity fading, and structural changes hinder its applications. The incorporation of graphene into Co 3 S 4 makes it a promising electrode by providing better electrochemical coupling, enhanced conductivity, fast mobility of ions and electrons, and a stabilized structure due to its elastic nature.…”

“…Thus, these properties endorse Co 3 S 4 /G composites as auspicious candidates for both LIBs and ORR. Keywords: cobalt · electrochemistry · lithium ion batteries · nanotubes · oxygen reduction reaction capacity fading, low conductivity, and poor cyclability; [18,23,[33][34][35] these are associated with the pulverization of electrodes, which results in the decay of the specific capacity and the formation of polysulfide anions. These polysulfide anions dissolve in the organic solvent of the electrolyte, which causes the low conductivity.…”

Electrochemical Properties for Co-Doped Pyrite with High Conductivity

“…The energy decrease of the (t2g) 6 electrons compensates for the energy required to promote the (eg) 1 electron into the antibonding σ* orbital, assuming that one Co atom contributes one charge carrier and replaces the Fe atom in the pyrite unit cell. In addition, according to reports, CoS2 is also a high-activity candidate electrode material for lithium-ion batteries [19], solar cells [20], and electrocatalysis [21].…”

Preparation of [C₆₀]Fullerene-CoS₂ Nanocomposites and Kinetics Study for Photocatalytic Degradation of Organic Dyes

“…5 According to a recent study, cobalt disulfide (CoS 2 ) is known to have higher thermal stability and electronic conductivity compared to other metal sulfides such as iron disulfide (FeS 2 ), nickel disulfide (NiS 2 ), and molybdenum disulfide (MoS 2 ). 5,6 Therefore, cobalt disulfide (CoS 2 ) of which the pyrite type structure likes cubic crystal has recently drawn substantial attention on the electrochemical and magnetic properties due to its potential application in lithium ion batteries, 1,5-8 spin-electronic devices, 6 magnetic materials, 7 supercapacitors, 1 catalysts, 1,7 and solar cells. 1,10 Also, cobalt disulfide (CoS 2 ) has a much lower solubility and higher electronic conductivity in molten electrolyte.…”