열 안정성이 높고 전해질 습윤성이 개선된 리튬 이온 배터리용 분리막으로 전기방사된 PVDF-HFP/PAN 혼합 나노섬유

Abstract

Battery stability is an emerging problem due to the poor thermal stability and electrolyte wettability of polyolefin-based separators used in lithium-ion batteries. Here, we describe a method to enhance the thermal stability and electrolyte wettability of polyolefin separator and to improve battery stability. An appropriate concentration was found to electrospun poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) with high ionic conductivity and polyacrylonitrile (PAN) with excellent thermal stability. In addition, we successfully manufactured a PVDF-HFP/PAN bicomponent separator. The bicomponent separator has the advantages of both PVDF-HFP and PAN, and the electrospinning separator formed in the stacked form exhibited high porosity (from 60% to 80%) as well as electrochemical stability. A battery using the PVDF-HFP/PAN composite separator exhibited superior cycle performance, efficiency, and C-rate performance compared with a battery using a polyethylene separator.