Analysis of the Influence of Coated PVDF ‐ Al ₂ O

ABSTRACT

This article uses a polypropylene separator for lithium‐ion batteries as the substrate, and evenly coats an inorganic slurry mixed with 100–200 nm alumina powder, binder, and dispersant on both sides of the separator to obtain a new type of ceramic coating separator. The thermal stability test of the separator shows that under a high temperature environment of 160°C, the thermal shrinkage rate of the inorganic ceramic coated separator is 5.0%, while the thermal shrinkage rate of the polypropylene separator is 11.67%, indicating that the coated separator has excellent thermal stability. Due to the high specific surface area of inorganic nano alumina particles, the coated separator can store more electrolytes compared to polypropylene separators at the same size. The LiFePO ₄ ‐Li system battery was assembled using ceramic coated separators and subjected to 1C charge discharge cycling tests. The results showed that the capacity retention rate of the battery assembled with coated separators after 100 cycles was 65.87%, which was higher than that of the battery assembled with polypropylene separators (60.42%), and could effectively improve the capacity retention performance of lithium‐ion batteries.