Gel electrolytes based on polyacrylonitrile/thermoplastic polyurethane/polystyrene for lithium-ion batteries

Li Tan,Yuewen Liu,Yuanyuan Deng,Xianyou Wang,Qi Cao,Bo Jing

doi:10.1007/s11581-019-02940-7

Abstract

Using an electrospinning method, high-performance gel polymer electrolytes (GPEs) comprising polyacrylonitrile/thermoplastic polyurethane/polystyrene (PAN/TPU/PS) were prepared. Then, these electrolytes were used to assemble button cells. The GPEs exhibited a maximum ionic conductivity of 3.9 × 10−3 S cm−1 at room temperature, with an electrochemical stability of 5.8 V. In addition, a Li/GPE/LiFePO4 cell showed first charge and discharge capacities of 161.70 mAh g−1 and 161.44 mAh g−1, respectively, at a 0.1 C rate and a stable cycle performance (the capacity retention was nearly 94% after 50 cycles) with high coulombic efficiency. Additionally, the SEM images showed that the PAN/TPU/PS was not composed of beaded-fibres in a fibrous membrane but was composed of fibres that were slim with a uniform size distribution. The uptake behaviour and porosity of the PAN/TPU/PS fibres showed the best performance and superior physical properties of the tested samples (the elongation at break of the film was 115.15%, and the tensile strength was 9.86 MPa). Considering these results, the PAN/TPU/PS blend/composite film has broad prospects for use in lithium-ion batteries.

Highlights

With the consumption of non-renewable resources, such as petroleum and coal, lithium-ion batteries (LIBs) have received attention as the first of the new energy technologies
Membranes based on PAN/Thermoplastic polyurethane (TPU), TPU/PS, PAN/PS, and PAN/ TPU/PS are prepared by electrospinning
The scanning electron microscopy (SEM) images and porosity measurements showed that the electrospun membranes have a uniform and highly interconnected porous structure

Summary

Introduction

With the consumption of non-renewable resources, such as petroleum and coal, lithium-ion batteries (LIBs) have received attention as the first of the new energy technologies. Gel polymer electrolytes (GPEs) [5,6,7] have the high ionic conductivities of liquid electrolytes [8,9,10] and have a series of advantages, such as solving the difficult problem of electrolyte leakage, flammability, and explosivity [11]. The application of gel polymer electrolytes in LIBs is still difficult [12, 13] because of their problems such as low ionic conductivities and poor mechanical strengths at room temperature. Polyacrylonitrile (PAN) [14,15,16,17,18] has outstanding properties, such as high thermal stability, high ionic conductivity, good compatibility with lithium electrodes, a wellformed morphology for electrolyte absorption, and the ability to minimise dendritic formation during the charge and discharge processes. To improve the mechanical stability, PAN has always been modified via copolymerization or blending with other materials

Methods

Results

Conclusion