Microfibril Aramid-Nanocellulose Fiber-Based Hybrid Separator for High-Performance Lithium-Ion Batteries

Abstract

The poor thermal stability and wettability of commercial polyolefin separators are safety hazards that limit the electrochemical performance of lithium-ion batteries (LIBs). In this work, a novel aramid-nanocellulose fiber-based hybrid separator (Aramid-NCF separator) was fabricated by an industrial one-step paper-making process. The separator showed excellent heat stability, suitable pore structure, and outstanding electrolyte wettability, with a contact angle close to 0°. The Aramid-NCF separator showed superior ionic conductivity of 5.491 × 10−4 S·cm−1 compared with an alumina-coated PE separator (PE-Al2O3 separator) (3.260 × 10−4 S·cm−1). LIBs with the Aramid-NCF separator also showed better C-rate performance, better cycling performance, and a higher capacity retention rate than batteries prepared with the PE-Al2O3 separator. A pouch battery with the Aramid-NCF showed a higher capacity retention rate (89.17% after 200 cycles at 0.5 C) than a pouch battery with the PE-Al2O3 separator (86.01% after 200 cycles at 0.5 C). Therefore, the Aramid-NCF separator is a promising candidate for next-generation LIBs.