Low-cost separator with dust-free fabric composite cellulose acetate toward stable dendrite-free aqueous zinc-ion batteries

Abstract

At present, the commonly used glass fiber (GF) separators in AZIBs possess many defects, such as lack zinophilic active sites, low ionic conductivity, poor mechanical strength, and high cost, which leading to the growth of dendrites and cause short circuits, thus resulting in deteriorated cyclic life. Herein, a novel CA@DF separator has been developed by coating molten blend of cellulose acetate (CA) and polyvinylidene fluoride (PVDF) on commercial dust-free fabric (DF) substrate and subsequent phase inversion. Due to the large number of active sites provided by the zinophilic –OH groups derived from CA, more the nucleation sites of Zn2+ are offered by the as-obtained CA@DF separator, which leads to an uniform deposition of Zn2+ of preferred (002) crystallographic orientation. Furthermore, as-obtained CA@DF separator demonstrate not only high tensile strength of 23.08 MPa, which is 51 times of the GF separator but also improved Zn2+ migration number (τ) (0.58 for CA@DF vs. 0.31 for GF). Moreover, the CA@DF separator has cost with only 1/221 cost of GF separator. Impressively, the symmetric cell equipped with the CA@DF separator displays an ultralong lifespan of over 2000 h at 0.5 mA cm−2 and 1000 h at 3 mA cm−2. Specifically, the CA@DF separator also improves the cycling stability of the Zn//V2O5 cell with a reversible capacity of 78 mAh g−1 at 1A g−1 after 1000 cycles. This simple, reliable, and low-cost separator provides new insights into the design and industrial production of electrochemical energy storage device separators.