Safety enhanced novel polymer electrolytes for lithium-ion battery: Anomalous output performance with long term cycling stability by doping and polymer blending

Abstract

Electrolyte with better safety and stability are the primary concern in the present lithium-ion battery (LIB) technology. Herein, a unique polymer blend electrolyte of polyvinylidene difluoride (PVdF)/poly (acrylonitrile butadiene styrene) (ABS) (75: 25) is fabricated by the non-solvent induced phase inversion method. The structural, morphological, and electrochemical performance of the PVdF/ABS blend is enhanced by incorporating the silica nanoparticles as the ceramic filler by the in-situ method. The gel polymer electrolyte (GPE) constitutes 6 wt % of in-situ synthesised silica in PVdF/ABS blend (PASI-06) exhibits better microporous structure with 80 % porosity. The thermal shrinkage, thermogravimetric analysis (TGA) and flammability test safeguards the exceptional thermal stability of the polymer membrane in LIBs. The polymer membrane activated in the liquid electrolyte (1 M LiPF6 in EC:EMC:DMC (1: 1: 1 v/v)) reveals an electrolyte uptake of 400 %, high electrolyte retention (0.82) and a room temperature ionic conductivity of 5.7 mS cm−1. The better oxidative stability exhibited by the PASI-06 (4.5 V) ensures its applicability with high voltage cathodes. Moreover, the electrochemical performance of the coin cell constitutes of Li/GPE/LFP able to exhibits an initial discharge capacity of 143 mAh g−1 and retained a capacity of 115 mAh g−1 even after 200 cycles at 0.1 C-rate at 25 °C. The long term cycling stability evaluated over 500 cycles at 1 C shows that the cell can exhibit an initial discharge capacity 120 mAh g−1 with 77 % capacity retention over 500 cycles that corresponds to 99 % of coulombic efficiency. These excellent performances exhibited by the PASI-06 GPE guarantee its applicability in thermally stable LIBs with better safety and reliability.