Electrospinning Equipment: Electrospinning Meets Heterostructures in Lithium-SulfurBatteries

Research background: With the popularity of portable electronic devices and electric vehicles, the demand for high - energy - density energy storage systems is increasing day by day. Lithium - sulfur (Li-S) batteries are regarded as strong candidates for future energy storage due to their high theoretical energy density (2600 Wh kg⁻¹), abundant sulfur resources, and environmental friendliness. However, their practical applications are hindered by many challenges: sulfur and its reduction products (Li₂S₂/Li₂S) have poor electrical conductivity, resulting in insufficient electrochemical reactions; the dissolution of lithium polysulfides (LiPSs) triggers the "shuttle effect", causing the loss of active materials; the volume expansion of sulfur during charging and discharging leads to the collapse of the electrode structure, affecting the cycling stability; the uneven deposition of lithium on the anode is likely to form lithium dendrites, which may pierce the separator and pose safety risks.

To address these challenges, the research team led by Professor Peng Zhang from the School of Materials Science and Engineering at Zhengzhou University published a comprehensive study titled "Electrospinning Meets Heterostructures in Lithium - Sulfur Batteries" in the international journal Small. This research focuses on Li-S batteries and comprehensively and deeply explores the applications of electrospinning technology and heterostructures in them, providing key guidance for research in this field.

（1）The Concept of Heterostructures and Their Applications in Lithium - Sulfur Batteries

Heterostructures are composed of two or more chemically - bonded solid - state materials, achieving multifunctional integration through the synergistic effect at the interfaces between different phases. Different from composite materials, it not only involves the physical integration of material advantages but also the reconstruction of the electronic structure.

In Li-S batteries, as the host for sulfur in the cathode, heterostructures can enhance the adsorption of LiPSs, alleviate volume expansion, and promote the uniform deposition of Li₂S. When used in the separator, they can increase the ion transport rate and improve the LiPSs shuttle effect. As the anode, they can serve as lithiophilic conductive scaffolds, enhance the uniform deposition of lithium, and homogenize the current density on the electrode surface. However, heterostructures have problems such as high manufacturing costs, unstable material structures, complex mechanisms, deactivation of active sites, and difficulties in size and dimension control.

（2）Applications of Heterostructures Constructed by Electrospinning in Lithium - Sulfur Batteries

Electrospinning technology, which relies on an electrospinning machine, can precisely control the morphology, diameter, and arrangement of nanofibers, realizing the micro - level design of heterostructures. The nanofibers prepared by electrospinning machine have a large surface area, which enhances the surface activity and interfacial effects, improving material performance. It can also uniformly mix materials with different properties to achieve multifunctional design. Moreover, it has low costs and is easy to prepare on a large scale, solving the preparation problems of heterostructured materials. The main applications of heterostructures prepared by electrospinning machine in Li-S batteries are as follows:

Sulfur Cathode: The applications of electrospun heterostructures in sulfur cathodes mainly include three types: carbon - based, metal - compound - based, and MXene - based. Carbon - based heterostructures make full use of the electrical conductivity and stability of carbon materials, combined with the polar properties of metals or metal compounds, to enhance the adsorption and catalytic ability for LiPSs. Metal - compound - based heterostructures accelerate the conversion of LiPSs through the synergistic effect between different metal compounds. MXene - based heterostructures utilize their high specific surface area and abundant active sites to increase the sulfur loading and electrochemical performance.

Separator: Electrospun heterostructures, produced by an electrospinning device, used as polymer - based separators also include three types: PAN - based, PVDF - based, and other polymer - based. PAN - based separators use their high porosity and excellent electrolyte affinity to effectively inhibit the LiPSs shuttle effect. PVDF - based separators enhance the mechanical strength and thermal stability, improving the safety and cycling life of the battery. Other polymer - based separators such as polyimide (PI) combine high thermal stability and electrochemical stability to further optimize the separator performance.

Lithium Anode: The applications of heterostructures in lithium anodes include two types: 3D lithiophilic scaffolds and 3D electron/ion - conducting scaffolds. 3D lithiophilic scaffolds inhibit the growth of lithium dendrites through uniform lithium deposition and adaptation to volume changes. 3D electron/ion - conducting scaffolds promote the uniform nucleation and growth of lithium through efficient electron and ion transport, improving the cycling stability and efficiency of the lithium anode.

This review discusses the synergistic effect of the combination of electrospinning technology and heterostructured materials, especially their potential in improving the electrochemical performance of Li-S batteries. It systematically studies the latest developments of electrospun heterostructured materials, providing a technical basis and strategic insights for the integrated application of electrospinning and heterostructured materials in Li-S batteries. The review not only summarizes the positive impacts of heterostructures prepared by electrospinning in Li-S batteries but also proposes new directions for future research.

Article Source: https://doi.org/10.1002/smll.202411838