Electrospining: Wearable flexible zinc-ion battery based on electrospinning technology

Background

In recent years, flexible and wearable electronics, as prominent technological trends in future lifestyles, have attracted widespread interest in the fields of artificial skin, rollable displays, smart clothing, smart glasses, smart textiles, and implantable medical devices (Figure 1). With the increasing demand for smart electronic products, people are unremittingly pursuing advanced flexible rechargeable power sources with high energy density and reliable electrochemical performance. Undoubtedly, lithium-ion batteries dominate various electronic devices with their advantages such as high energy density, high output voltage, and low self-discharge, and are the main energy source for today's flexible electronic products. However, the scarcity and uneven distribution of lithium resources, the potential leakage of organic electrolytes, and the risk of corrosion have greatly limited the further application of lithium-ion batteries. Therefore, it is imperative to explore a new generation of highly safe, environmentally friendly, and low-cost rechargeable flexible batteries.

The main point of this paper

Advantages of zinc-based batteries (ZIBs):

ZIBs are considered to be a more viable alternative to lithium-ion batteries because zinc reserves are abundant, cost-effective, and use water-based electrolytes, which are safer and less prone to thermal runaway, fire, and electrolyte leakage.

Importance of electrospinning technology:

Electrospinning is a simple and versatile method that can continuously prepare nanofiber materials with large specific surface area, multiple active sites, and good flexibility, suitable for industrial production.

Adjustability of raw materials and structures for electrospinning:

Electrospinning is suitable for a variety of polymers, including polymers soluble in water/organic solvents, such as PVDF, PAN, PP, etc., and even insoluble and immiscible polymers such as PTFE.

By changing the electrospinning parameters, nanofibers with different structures (such as porous, hollow) can be prepared and doped and composite modified.

Application of electrospinning in ZIBs:

The three-dimensional (3D) network structure formed by the nanomaterials prepared by electrospinning helps to improve the structural stability and Zn2+ transfer, thereby improving the electrochemical performance.

Electrospun nanofibers (ESNFs) are used in various configurations of ZIBs, such as cathode, anode, and separator.

Technical Challenges:

The technical challenges faced by ZIBs include electrode dissolution and structural collapse on the cathode side, and zinc dendrite growth, hydrogen evolution, and corrosion problems on the anode side.

Application progress and challenges of electrospinning technology in flexible zinc-ion batteries

Demand for flexible wearable batteries:

With the development of smart devices, there is a growing demand for thin, lightweight and small flexible wearable batteries, which are used in smart watches, foldable phones, fitness trackers and other fields.

Advantages of zinc-based batteries (ZIBs):

ZIBs are considered to be the best alternative to flexible lithium-ion batteries (LIBs) due to their low cost, high safety and eco-friendliness.

Characteristics of electrospun nanofibers:

Electrospun nanofibers have low density, high porosity, large specific surface area and good flexibility, which make them potential for application in wearable FZIBs.

Versatility of electrospinning technology:

Electrospinning technology can achieve the multifunctionality of nanofibers through structural design and the incorporation of multifunctional materials, which is suitable for cathodes, anodes, separators, polymer electrolytes and integrated flexible batteries of FZIBs.

Scope of application of electrospinning technology:

This paper reviews the wide application of electrospinning technology in FZIBs, including the research progress of electrode materials, separators and electrolytes

Summary

With the development of ZIBs, FZIBs are now considered a sustainable option for powering portable electronic devices. Recent studies have shown that the preparation of electrospun FZBs provides an effective means and has unique advantages: (1) By modulating the precursor solution, electrospinning can prepare common nanoscale anode and cathode materials; (2) By adjusting the electrospinning process and post-treatment, the morphology, structure and composition of the electrospun materials can be well controlled; (3) The one-dimensional nanostructures prepared by electrospinning can be interconnected into a three-dimensional network, which improves the conductivity and structural stability by promoting electron/ion transfer. The three-dimensional network generally behaves as a flexible fiber membrane, which is conducive to the preparation of binder-free self-supporting flexible electrodes. Therefore, electrospinning technology provides an effective way to realize FZBs.

This paper first introduces the basic principles of electrospinning and discusses that by precisely adjusting the electrospinning process parameters, composite nanofiber materials with a variety of structures and compositions can be prepared for various components of batteries (cathode, anode, separator and polymer electrolyte). Then the basic principles of FZBs and some existing problems are outlined, and the application of ESFS in FZBs is summarized. Although electrospinning has many advantages in producing high-performance, safe and reliable FZBs and has been widely studied, there are still some problems and challenges in its future development, which require further exploration and innovative technology upgrades.