Open-framework indium hexacyanoferrate for high-voltage and coaxially-fibrous aqueous K//Zn battery.

[Display omitted] • The as-synthesized InHCF exhibits satisfied K+-storage performance. • DFT and experiment results reveal that the InHCF preferentially achieves K+ (de)intercalation rather than Zn2+. • The InHCF can deliver a high capacity of 60.6 mAh g−1 and prominent rate capability. • A novel single coaxially-fibrous K//Zn battery was successfully assembled with a high discharge plateau of 1.7 V. • The CFAR K//Zn battery shows high energy density, excellent weavability and mechanical flexibility. The design of eco-friendly fibrous aqueous rechargeable Zn-based batteries is important for the advancement of flexible electronics. But it is still remains extremely difficult to develop high-voltage fibrous Zn-based batteries on a single-fiber architecture that directly influence their energy density. Furthermore, the sluggish Zn2+ diffusion kinetics and tough electrostatic interaction seriously astrict to further move ahead for the Zn-based batteries. Herein, we demonstrate a high-voltage coaxially-fibrous aqueous rechargeable (CFAR) K//Zn battery based on open-framework indium hexacyanoferrate (InHCF) cathode. The resultant assembled CFAR K//Zn battery provides an eminent voltage of 1.70 V and a superhigh energy density of 197.88 mWh cm-3 at 170.4 mW cm-3. More importantly, our assembled CFAR K//Zn battery exhibits excellent mechanical steadiness with the capacity retention of 92.7 % by following bending at 90° for 4000 times. Therefore, the design of the new-style architecture in high-voltage CFAR K//Zn batteries provides a fresh strategy for economic, reliable, and high-energy-density wearable energy-storage devices. [ABSTRACT FROM AUTHOR]