Chen Fan, Li Xuan, Chen Shi-Peng, Zhang Yilin, Huang Hua-Dong, Yang Hongli, Zhou Shengyang, Li Zhong-Ming
College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China.
College of Polymer Science and Engineering, Sichuan University, Chengdu, 610065, China.
Adv Sci (Weinh). 2025 Jul 29:e11759. doi: 10.1002/advs.202511759.
Recent advancements in hydrogel electrolytes for aqueous zinc-ion batteries (AZIBs) have drawn considerable interest due to their soft nature, offering potential to overcome challenges including reversibility and flexibility. As the most abundant natural polymer, cellulose is ideal for AZIB hydrogel electrolytes due to rich hydroxyls with stable hydrogen-bonded networks for water retention. However, conventional cellulose hydrogels suffer from low Zn conductivity and insufficient mechanical robustness, usually requiring additional polymers to meet practical demands. This work reports a chemically neutral dissolution system combined with Keggin-type polyoxometalate as a bifunctional crosslinker and electrolyte modulator. This approach results in ultra-low solvation of Zn in cellulose hydrogel, contributing to a wide 2.48 V electrochemical stability window. The high-desolvation hydrogel exhibits balanced Zn reaction stability and transport kinetics, effectively suppressing dendrite growth and parasitic reactions. The Zn electrode can be stably strapped/plated with this hydrogel for thousands of cycles with minimal Coulomb efficiency change. The hydrogel also shows excellent flexibility, with toughness of 1.5 MJ m and elongation at break of 80%. Pouch cells assembled with this hydrogel demonstrate high mechanical flexibility and stability under deformations. This pioneering cellulose dissolution and crosslinking chemistry paves the way for practical application of flexible, durable AZIBs.
用于水系锌离子电池（AZIBs）的水凝胶电解质的最新进展因其柔软的性质而引起了广泛关注，有望克服包括可逆性和柔韧性在内的挑战。作为最丰富的天然聚合物，纤维素由于富含羟基且具有用于保水的稳定氢键网络，是AZIB水凝胶电解质的理想选择。然而，传统的纤维素水凝胶存在锌离子电导率低和机械强度不足的问题，通常需要添加其他聚合物来满足实际需求。这项工作报道了一种化学中性的溶解体系，该体系结合了Keggin型多金属氧酸盐作为双功能交联剂和电解质调节剂。这种方法导致纤维素水凝胶中锌的溶剂化程度极低，从而形成了宽达2.48 V的电化学稳定窗口。高去溶剂化水凝胶表现出平衡的锌反应稳定性和传输动力学，有效抑制了枝晶生长和寄生反应。使用这种水凝胶，锌电极可以稳定地进行数千次循环的充放电，库仑效率变化极小。该水凝胶还具有出色的柔韧性，韧性为1.5 MJ m，断裂伸长率为80%。用这种水凝胶组装的软包电池在变形情况下表现出高机械柔韧性和稳定性。这种开创性的纤维素溶解和交联化学为柔性、耐用的AZIBs的实际应用铺平了道路。
