Fiber-shaped aqueous zinc-ion batteries (FAZIBs) with intrinsic safety, high theoretical capacity and superb omnidirectional flexibility hold promise for wearable energy-supply devices. However, the interfacial separation of fiber-shaped electrodes and electrolyte caused by Zn stripping process and severe Zn dendrites occurred at folded area under bending condition seriously restrict FAZIBs' practical application. Here, an advanced confinement encapsulation strategy is originally reported to construct dual-layer gel electrolytes consisting of high-fluidity polyvinyl alcohol-Zn acetate inner layer and high-strength Zn alginate outer layer for fiber-shaped Zn anode. Benefiting from the synergistic effect of inner-outer gel electrolytes and the formation of solid electrolyte interphase on Zn anode surface by lysine additive, the resulting fiber-shaped Zn-Zn symmetric cell delivers long cycling life over 800 h at 1 mA·cm-2 with dynamic bending frequency of 0.1 Hz. The finite element simulation further confirms that dual-layer gel electrolytes can effectively suppress the interfacial separation arising from the Zn stripping and bending process. More importantly, a robust twisted fiber-shaped Zn/zinc hexacyanoferrate battery based on dual-layer gel electrolyte is successfully assembled, achieving remarkable capacity retention of 97.7% after bending 500 cycles. Therefore, such novel dual-layer gel electrolyte design paves the way for the development of long-life fiber-shaped aqueous metal batteries.
Figure 1. (a) The schematic illustration of as-fabricated FAZIB; (b) CV profiles of the as- assembled FAZIB at various scan rates; (c) GCD splines of FAZIB at various current densities; (d) Rate performance of our FAZIB; (e) Cyclic property and Coulombic efficiency of as- assembled FAZIB, Inset: GCD splines at selected cycle; (f) Schematic illustrations of FAZIB at bending states; (g) the capacity of FAZIB versus bending angles; (h) Photograph of a red light-emitting diode powered by a FAZIB device under bending situation.
The above result entitled “High-Fluidity/High-Strength Dual-Layer Gel Electrolytes Enable Ultra-flexible and Dendrite-Free Fiber-Shaped Aqueous Zinc Metal Battery” is published on Advanced Materials. Prof. Yaogang Yao and Prof. Qichong Zhang are the corresponding authors of the paper. Chaowei Li and Wenhui Wang are the co-first authors. This work was supported by the National Key R&D Program of China, the Natural Science Foundation of Jiangsu Province, Anyang City science and technology research project, Green Tech Fund, and City University of Hong Kong.
Article Link: https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202313772
