Hydrogel electrolytes based on natural polymers have attracted increasing attention in zinc-ion batteries (ZIBs) powering wearable and implantable electronics, but designing natural polymer hydrogels with high ionic conductivity, excellent transference performance, and inhibited Zn dendrites is still challenging. Herein, two natural biocompatible polymers (sodium alginate (SA) and agarose (AG)) are used to prepare composite hydrogel electrolytes ensuring electrostatic interaction between –COO^– groups in SA and Zn²⁺ and coordination between C–O–C groups in AG and Zn²⁺. The as-obtained hydrogels exhibit an elevated ionic conductivity (25.05 mS cm⁻¹) with a high transference number (0.75), useful for facilitated efficient Zn²⁺ transport. The theoretical calculations combined with experimental results reveal C–O–C groups endowing the as-prepared hydrogels with improved desolvation kinetics and capture ability of Zn²⁺ for achieving dendrite-free Zn deposition. In this way, the assembled Zn symmetric cell shows a long cycle life reaching 700 h at 0.2 mA cm⁻². The exceptional biocompatibility of the hydrogels also results in cell viability assay with a survival rate above 93.5%. Overall, the proposed hydrogel electrolytes endow solid-state ZIBs with high discharge capacity, outstanding rate performance, long cycle life, good antifreeze capability, and impressive flexibility, useful features for future design and development of advanced ZIBs.

中文翻译：

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生物相容性水凝胶电解质，具有高离子电导率和向无枝晶 Zn 阳极的转移数


基于天然聚合物的水凝胶电解质在为可穿戴和植入电子产品供电的锌离子电池 （ZIB） 中引起了越来越多的关注，但设计具有高离子导电性、优异转移性能和抑制 Zn 枝晶的天然聚合物水凝胶仍然具有挑战性。在此，两种天然生物相容性聚合物（海藻酸钠 （SA） 和琼脂糖 （AG））用于制备复合水凝胶电解质，确保 SA 和 Zn ²⁺ 中 –COO ^– 基团之间的静电相互作用以及 AG 和 Zn ²⁺ 中 C-O-C 基团之间的协调。所获得的水凝胶表现出较高的离子电导率 （25.05 mS cm ⁻¹ ） 和高迁移数 （0.75），有助于促进 Zn ²⁺ 的高效传输。理论计算与实验结果相结合，揭示了 C-O-C 基团，使所制备的水凝胶具有更好的脱溶剂化动力学和 Zn ²⁺ 捕获能力，可实现无枝晶的 Zn 沉积。通过这种方式，组装的 Zn 对称电池在 0.2 mA cm ⁻² 处显示出长达 700 小时的长循环寿命。水凝胶出色的生物相容性也导致细胞活力测定的存活率高于 93.5%。总体而言，所提出的水凝胶电解质赋予固态 ZIB 高放电容量、出色的倍率性能、长循环寿命、良好的防冻能力和令人印象深刻的灵活性，为未来先进 ZIB 的设计和开发提供了有用的功能。