Superior Stability Cellulose Composite Separators Enable High-Rate Zinc Ion Batteries with Ultralong Cycle Life.

Teng, Qijin; Zhang, Zuocai; Han, Renyang; Zhu, Nannan; Xing, Yibin; Wang, Xiyao; Du, Bing; Wan, Xuejuan · Nano Lett · 2025

basic_science · Level V

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Abstract

Aqueous zinc ion batteries (AZIBs) are preferred for safety and cost-effectiveness but encounter challenges like zinc dendrite growth and side reactions, reducing their lifespan. Herein, a composite separator (CSC) for AZIBs is prepared using carboxylate sisal fiber (CSF) and sulfonation cotton fiber (SCF), followed by cross-linking with citric acid (CA). The exceptional stability of CSC─including high mechanical strength, wide pH tolerance, and suppression of hydrogen evolution─combined with high zinc ion migration number (<i>t</i><sub><i>Zn</i></sub><sup><i>2+</i></sup> = 0.70), leads to its remarkable electrochemical performance. The cycle life of Zn//Zn batteries with CSC is over 6400 and 400 h at 5 mA cm<sup>-2</sup> and 20 mA cm<sup>-2</sup>, respectively. A Zn//MnO<sub>2</sub> full battery exhibits 92.85% capacity retention after 10000 cycles at 5 A g<sup>-1</sup> (∼16C), significantly outperforming the widely used commercial separators in AZIBs like glass fiber (GF). This work presents a highly effective but simple separator design strategy to achieve long-cycling, high-rate AZIBs.