Effects of Island-Coated PVdF-HFP Composite Separator on the Performance of Commercial Lithium-ion Batteries

Abstract

The widespread industrialization of high-energy density commercial lithium-ion batteries has long been challenged by issues of safety and efficiency stemming from uncontrollable lithium dendritic growths. Here, an island-coated composite separator has been fabricated using a pre-swelling process with water-based dispersions to address the issue of dendrite growth. The pre-swelling of the polymer particle surface balances the contradiction between the high crystallinity and electrolyte compatibility showing high electrolyte wettability and electrolyte uptake ability. Furthermore, the point-to-point surface structure can balance the high interfacial adhesion of electrodes and anti-deformation ability well, which is beneficial for preventing ripple-shaped and pot-shaped deformation, smoothing the solid particle morphology of the electrode and achieving a steady interfacial structure for lithium diffusion in cells. This new strategy constructs a non-continuous novel structure, achieving greatly improved dendrite growth suppressing and cell interface stabilization. This paper has opened up a new method for the development of low cost, simple process and easy industry of the lithium-ion pouch cell with improved quality and efficiency.