A novel electrospinning polyacrylonitrile separator with dip-coating of zeolite and phenoxy resin for Li-ion batteries

Abstract

Commercial separators (polyolefin separators) for lithium-ion batteries still have defects such as low thermostability and inferior interface compatibility, which result in serious potential safety distress and poor electrochemical performance. Zeolite/Polyacrylonitrile (Z/PAN) composite separators have been fabricated by electrospinning a polyacrylonitrile (PAN) membrane and then dip-coating it with zeolite (ZSM-5). Different from commercial separators, the Z/PAN composite separators exhibit high electrolyte uptake, excellent ionic conductivity, and prominent thermal stability. Specifically, the Z/PAN-1.5 separator exhibits the best performance, with a high electrolyte uptake of 308.1% and an excellent ionic conductivity of 2.158 mS·cm−1. The Z/PAN-1.5 separator may mechanically shrink less than 10% when held at 180◦C for 30 min, proving good thermal stability. Compared with the pristine PAN separator, the Li/separator/LiFePO4 cells with the Z/PAN-1.5 composite separator have excellent high-rate discharge capacity (102.2 mAh·g−1 at 7 C) and favorable cycling performance (144.9 mAh·g−1 at 0.5 C after 100 cycles). Obviously, the Z/PAN-1.5 separator holds great promise in furthering the safety and performance of lithium-ion batteries.