High-security organic PVDF-coated SiO2 aerogel lithium battery separator

Silica aerogel membranes are renowned for their high porosity and superior thermal insulation capabilities. However, they are known to have limited mechanical strength and tend to shed surface particles easily. To address these drawbacks, a novel PVDF/SiO₂/PVDF(PSP) composite membrane with a three-layered structure has been successfully fabricated by coating the surface of silica aerogel membranes with polyvinylidene fluoride (PVDF) using a straightforward and effective coating technique. This innovative approach not only effectively addresses the issue of particle shedding but also endows the silica aerogel membrane with organic functionality. The resulting PSP membranes offer significant improvements over traditional polyolefin separators, including higher porosity, enhanced electrolyte affinity, and superior thermal dimensional stability. These membranes boast an impressive ionic conductivity of 1.405 mS/cm and a lithium-ion transference number of 0.550. Moreover, when incorporated into a LiFePO₄-based coin battery, the PSP membranes deliver a remarkable discharge-specific capacity of 143.5 mAh/g and an impressive capacity retention rate of 93.7% after undergoing 200 charge/discharge cycles at a rate of 0.5C.

Graphical abstract