Preparation and Performance of PAN/PS/PMMA Ternary Blend-Modified Fiber Membranes via Centrifugal Spinning for Lithium-Ion Batteries

Abstract

Addressing the issues of poor thermal resistance in conventional polyolefin separators and the low production efficiency of electrospinning, this study innovatively employed high-efficiency centrifugal spinning technology to fabricate a ternary blended modified fiber membrane composed of polyacrylonitrile (PAN), polystyrene (PS), and polymethyl methacrylate (PMMA). By precisely adjusting the polymer ratio (8:2:2) and fine-tuning the spinning process parameters, a separator with a three-dimensional network structure was successfully produced. The research results indicate that the separator exhibited excellent overall performance, with a porosity of 75.87%, an electrolyte absorption rate of up to 346%, and a thermal shrinkage of less than 3% after 1 h at 150 °C, along with a tensile strength reaching 23.48 MPa. A lithium-ion battery assembled with this separator delivered an initial discharge capacity of 159 mAh/g at a 0.2 C rate and maintained a capacity retention of 98.11% after 25 cycles. Moreover, under current rates of 0.5, 1.0, and 2.0 C, the battery assembled with the ASM-14 configuration achieved high discharge capacities of 148, 136, and 116 mAh/g, respectively. This study offers a novel design strategy for modifying multi-component polymer battery separators.

Keywords: blending modification; centrifugal spinning; fiber membranes; poly(methyl methacrylate); polystyrene.

Figure 1

Preparation of fiber membranes using the centrifugal spinning technique and battery assembly.

Figure 2

SEM images of the fiber membranes: (a) ASM-1; (b) ASM-3; (c) ASM-6; (d) ASM-14.

Figure 3

Fiber diameter distribution of the PAN/PS/PMMA membranes: (a) ASM-1; (b) ASM-3; (c) ASM-6; (d) ASM-14.

Figure 4

X-ray diffraction and EDS mapping of the PAN/PS/PMMA fibers: (a) XRD pattern; (b) SEM image; (c) oxygen-element mapping; (d) nitrogen element mapping.

Figure 5

Initial and 30-s contact angles of the separators.

Figure 6

Electrolyte uptake and mechanical properties of the separator (a) porosity and electrolyte absorption rate of the membrane; (b) tensile strength of the membrane.

Figure 7

Comparison of the membranes before and after heating at 150 °C for 1 h.

Figure 8

Thermal stability of the separator: (a) TGA curves of the PAN/PS/PMMA fiber membrane and Celgard 2400; (b) DSC curves the of PAN/PS/PMMA fiber membrane and Celgard 2400.

Figure 9

Electrochemical performance of batteries assembled with the separators and comparison with other reported studies: (a) Initial charge–discharge performance; (b) cycling stability; (c) rate performance; (d) performance comparison between this study and previously reported works [41,42,45,50,52,53,54,55].