硫基复合材料的制备与电化学性能研究.docx

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Abstract:
Sulfur-based composite materials have been widely utilized in various energy storage devices such as lithium-sulfur batteries and supercapacitors due to their high specific capacity, low cost, and environmental friendliness. In this paper, we review the recent advances in the preparation methods and electrochemical performances of sulfur-based composite materials, including sulfur-carbon composites, sulfur-metal composites, and sulfur-polymer composites. The structure, morphology, and electrochemical properties of these composites are discussed in detail, providing insights into the design and optimization of sulfur-based composite materials for future energy storage applications.
Introduction:
With the increasing demand for renewable energy and green transportation, high-performance energy storage devices have attracted wide attention. Lithium-ion batteries (LIBs) have been widely used in portable electronic devices and electric vehicles due to their high energy density and long cycle life. However, the limited resource of lithium and the safety issues caused by the flammability of the organic electrolyte have hindered the further development of LIBs. As an alternative, lithium-sulfur batteries (LSBs), which utilize sulfur as the cathode material, have received great attention due to their high theoretical specific capacity (1675 mAh g-1), low cost, and environmental friendliness.
However, the practical application of LSBs is still hindered by some issues such as low conductivity of sulfur, poor cycle stability, and the dissolution of polysulfides. To overcome these issues, various strategies have been developed, one of which is the preparation of sulfur-based composite materials. The incorporation of sulfur into a conductive matrix can enhance its conductivity, inhibit the dissolution of polysulfides, and improve the overall electrochemical performance of LSBs.
This paper provides an overview of the recent advances in the preparation methods and electrochemical performances of sulfur-based composite materials for energy storage devices.
Preparation of sulfur-based composite materials:
Sulfur-carbon composites:
Carbon materials have been widely used as a conductive matrix for sulfur-based composite materials due to their high conductivity, chemical stability, and cost-effectiveness. Various carbon materials such as graphene, carbon nanotubes (CNTs), activated carbon, and carbon black have been used for the preparation of sulfur-carbon composites.
One of the commonly used methods is the melt-diffusion method, where sulfur and carbon are mixed and heat-treated to form a composite material. This method can effectively inhibit the dissolution of polysulfides and improve the cycle stability of LSBs. For example, Liu et al. reported a sulfur-graphene composite prepared by the melt-diffusion method, which showed a high specific capacity of 1162 mAh g-1 at C and a stable cycling performance up to 100 cycles.
Sulfur-metal composites:
The incorporation of metal nanoparticles into sulfur-based composite materials can provide additional active sites for redox reactions and enhance the electrical conductivity of the composite. Various metal nanoparticles such as Cu, Ni, Co, and Fe have been used for the preparation of sulfur-metal composites.
One of the commonly used methods is the chemical deposition method, where metal nanoparticles are deposited onto the surface of sulfur particles. For example, Li et al. prepared a sulfur-Cu composite by the chemical deposition method, which showed a high specific capacity of 1241 mAh g-1 at C and a stable cycling performance up to 50 cycles.
Sulfur-polymer composites:
Polymer materials have been used as a binder for sulfur-based composite materials to improve the mechanical strength and stability of the composite. Various polymer materials such as polyvinyl alcohol (PVA), polyacrylonitrile (PAN), and polyethylene oxide (PEO) have been used for the preparation of sulfur-polymer composites.
One of the commonly used methods is the solution-casting method, where a polymer solution and sulfur are mixed and cast into a film. For example, Tao et al. reported a sulfur-PVA composite prepared by the solution-casting method, which showed a high specific capacity of 1321 mAh g-1 at C and a stable cycling performance up to 100 cycles.
Electrochemical performance of sulfur-based composite materials:
The electrochemical performance of sulfur-based composite materials can be evaluated by various techniques such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge measurements.
The CV curves of sulfur-based composite materials show distinct peaks corresponding to the redox reactions of sulfur and polysulfides. The peak position and intensity can reflect the electrochemical activity and stability of the composite. The EIS spectra of sulfur-based composite materials can provide information about the charge transfer resistance and electrochemical reactions at the interfaces. The galvanostatic charge-discharge curves of sulfur-based composite materials can indicate the specific capacity, cycling stability, and rate capability of the composite.
Conclusion:
Sulfur-based composite materials have shown great potential for energy storage applications due to their high specific capacity, low cost, and environmental friendliness. The preparation methods and electrochemical performances of sulfur-based composite materials have been reviewed in this paper, including sulfur-carbon composites, sulfur-metal composites, and sulfur-polymer composites. The structure, morphology, and electrochemical properties of these composites are discussed in detail, providing insights into the design and optimization of sulfur-based composite materials for future energy storage applications.