One-Pot Synthesis of an FeS@GQDs Composite for Lithium Storage with Coal Tar Pitch as ″Natural GQDs″

Abstract

Graphene quantum dots (GQDs), a newly emerging zero-dimensional material, have achieved widespread interest in energy storage applications. However, the complicated preparation processes of GQDs involving harsh reagents/conditions, cumbersome purification procedures, or costly precursors hinder their practical use. Herein, we reveal a low-cost and eco-friendly solvothermal method to obtain an FeS@GQDs composite, with coal tar pitch (CTP) as ″natural GQDs″. When evaluated as an anode material in lithium-ion batteries (LIBs), this composite delivers an outstanding reversible capacity of 718.7 mAh g–1 over 200 cycles at 100 mA g–1; as comparison, the reversible capacity of pure FeS is only 16.3 mAh g–1 in the same situation. Furthermore, the FeS@GQDs composite shows much better rate performance and higher initial Coulombic efficiency than pure FeS. These prominent electrochemical properties of the FeS@GQDs composite profit from the successful coupling between FeS and GQDs by forming C–S–C, which provides a large specific surface area and well-developed porosity, leading to improved electrical conductivity and enhanced structure stability. In terms of energy storage, this approach is a potential way to prepare GQDs-based composites on a large scale without the expensive precursors, harsh reagents, as well as complex preparation conditions.

Low-Temperature Solvothermal Method for Coal Tar-Based Carbonaceous Mesophase Preparation and Its Excellent Performance

“…Moreover, the small semicircle in the high-frequency region represents the performance dynamics within the electrode material, and activated CMs-650 exhibited a much shorter portion of the Warburg region than activated CMs-700, suggesting better ion diffusion efficiency. These results are consistent with those obtained from the CV curve and constant current charge–discharge tests. , …”

“…These results are consistent with those obtained from the CV curve and constant current charge− discharge tests. 27,28 To further evaluate the electrochemical properties and the cycling performance, as depicted in Figure 10a, a plot of specific capacitance as a function of the cycle number was conducted at a current density of 0.5 A/g for up to 2000 cycles. The loss in specific capacitance based on the maximum value after 2000 cycles was about 3.31%, and the charge/discharge curves can maintain triangular shapes, thus suggesting excellent cycling stability.…”

Salt-assisted synthesis of advanced carbon-based materials for energy-related applications

“…These prominent electrochemical properties can be ascribed to the successful coupling between FeS and GQDs by forming C-S-C, which provides a large specific surface area and well-developed porosity, leading to improved electrical conductivity and enhanced structural stability. 203 Jiang et al reported a FeS 2 / NPCF composite using C 6 H 5 O 7 (NH 4 ) 3 as carbon source, FeCl 3 as iron source, and NaCl as template. The resulting FeS 2 /NPCF composite showed excellent sodium storage performance with a reversible capacity of 552 mA h g −1 and a capacity retention of 87% after 100 cycles.…”

Perspective of Vanadium Disulfide: A Rising Star Finds Plenty of Room in Single and Multielectron Energy Storage

“…Compounding with other materials can alleviate the volume change, enhance the structural stability, reduce the dissolution of active substances, adjust the electronic structure, and improve the conductivity. − It is one of the effective strategies to enhance the energy storage dynamics of the electrode and to improve the electrochemical performance. At present, VS 2 -based composites have shown advantages in electrochemical energy storage, such as carbon (e.g., carbon nanotubes, CNTs), , inorganic compounds (e.g., MoS 2 ), and conductive polymers (e.g., PEDOT–PSS, poly­(3,4-ethylenedioxythiophene)-poly­(styrenesulfonate), etc.).…”