Academic News

Nanofiber solid electrolyte membrane

Views: 2 Author: Site Editor Publish Time: 2024-10-15 Origin: Site

◆Background

In recent years, with the rapid development of new energy vehicle technology, all-solid-state batteries have attracted more and more attention as the next generation of power battery technology. As one of the key materials, solid electrolyte is the key to developing the next generation of high-energy, high-safety rechargeable batteries. To achieve all-solid-state batteries (ASSBs) beyond the theoretical energy density of state-of-the-art lithium-ion batteries (LiBs), a thin and robust solid electrolyte layer is essential.Solid electrolytes are mainly divided into three categories: inorganic solid electrolyte (ISEs), solid polymer electrolyte (SPEs) and composite solid polymer electrolyte (CSPEs), among which polymer solid electrolyte (SPE) has been widely studied because of its advantages of high safety, viscoelasticity, easy forming and thermal stability.

Solid-state battery

solid electrolyte membrane

◆Organic solid electrolyte

Organic solid electrolytes are divided into organic solid polymer electrolytes and solid composite electrolytes. Common materials used for polymer solid electrolytes include: PEO, PAN, PMMA, PVDF/PVDF-HFP, and solid composite electrolytes are mainly polymer-inorganic composite electrolytes. Common preparation methods include solid phase ball milling method, sol-gel method, co-precipitation method, spray drying method, chemical vapor deposition method, among which sol-gel method commonly used preparation methods are solution pouring method, phase transformation method, in-situ polymerization method, UV curing .

1、Sol-gel method

Solution pouring method

Phase transition method

In-situ polymerization method

UV curing method

Electrospinning method

During drying, small molecules of volatile substances cause the gel to shrink sharply and become brittle, creating small holes in the film.

Generally only applicable to polyvinylidene fluoride (PVDF) and its copolymers, other high-strength gel electrolytes can be prepared by combining the support structure.

Reactants are expensive, in situ polymerization applications of the substrate is relatively limited, most of the choice of poor thermal stability of the polymer, a small amount of use of insoluble elastomers.

The film formed by UV curing has low mechanical strength, which is not conducive to inhibiting the lithium dendrites and maintaining the safety of the battery, and needs to be combined with other polymers.

Nanofiber membrane has good electrolyte adsorption performance, uniform pore size distribution, suitable specific surface area and good liquid electrolyte compatibility.

With good polymer processing ability, the technology is simple and convenient. Different material systems and composite material systems can be prepared to make the performance of the membrane more excellent. Low cost mass production can be achieved by amplifying equipment and combining multiple processes.

2、Electrospinning - solid state composite electrolyte

Electrospinning technology has great advantages in the preparation of nanofiber materials, such as simple operation, controllable size and arrangement, and good scalability. One-dimensional nanomaterials with solid, hollow, porous, core-shell and interconnect structures can be prepared, and the thickness of electrolyte films can be reduced. The 3D supporting skeleton is provided and can be combined with other methods (gas-solid reaction, hot pressing, solution pouring, sol-gel method, etc.) to obtain composite materials with different compositions and structures, which has broad application prospects for the preparation of inorganic organic composite solid electrolytes with high performance.

	Schematic illustration
Electrospinning + solution pouring method
Electrospinning + solution coating method
Electrospinning + calendering process
Electrospinning + electrospraying + hot pressing
Coaxial electrospinning
Electrospinning + electrospray + impregnation + calender
Conclusion: The main properties of composite solid electrolyte are determined by the composition of inorganic and organic materials. The performance of solid electrolyte can be effectively improved by the structural design of polymer matrix and inorganic filler.In addition, nanomaterials with large specific surface area and porosity provide a fast channel for ion transport, forming self-support and effectively reducing the thickness of the electrolyte film.The ionic conductivity, mechanical strength and thermal stability can be improved by adding different types of nano-inorganic fillers to the polymer matrix.