Polypropylene/silica nanocomposite membranes for lithium‐ion battery separator: Studies on interfacial tuning of pore structure, mechanical and thermal properties

Abstract

Abstract Energy storage and mobility industries use polypropylene (PP) nanocomposites. The energy storage applications of newly made microporous SiO2 filled, porous PP nanocomposites combining PP, natural rubber, and SiO2 nanoparticles then subsequently removing natural rubber from the nanocomposite were explored in this paper. SEM pictures showed how the pore morphology was altered by nanofillers. Mechanical tensile tests reveal that the SiO2 nanofiller enhances the mechanical properties of microporous polypropylene. XRD and DSC experiments have shown that SiO2 nanoparticles works as a nucleating agent but has no impact on the crystallinity of PP. The electrolyte absorption, porosity, ionic conductivity, wettability and charge–discharge performance were investigated for PP/SiO2 nanocomposite separator. SiO2 nanoparticles in the matrix have a significant impact on the wettability of PP membrane, since the presence of SiO2 nanoparticle reduces the contact angle from 24° to 15°. SiO2 filled PP membrane outperformed microporous PP and celgard separator in terms of electrolyte uptake (230%) and porosity (62%). In comparison to microporous PP, the PP/SiO2 membrane demonstrated a better ionic conductivity (5.9 × 10−4 S cm−1). Finally, Li/PP‐SiO2/LiFePO4 coin cells (2320 type) were fabricated and delivered a discharge capacity of 138 mAh g−1.

Keywords

• nanocomposite
• polypropylene
• silica
• structure–property relations