Manipulating Zn 002 deposition plane with zirconium ion crosslinked hydrogel electrolyte toward dendrite free Zn metal anodes

Abstract

The practical applications of aqueous zinc (Zn) metal anodes are severely impeded by side reaction and dendrite formations on the Zn surface. Herein, a silk fibroin-based hydrogel electrolyte, cross-linked by a high valent cation of Zr⁴⁺ (SFPAM-Zr), was engineered to regulate the Zn²⁺ deposition and nucleation behavior for high-performance Zn metal anodes. We demonstrate that the Zr⁴⁺ can enhance the mechanical property of the hydrogel electrolyte for a stable electrochemical interface. In addition, the strong electrostatic shielding effect of Zr⁴⁺ can guide Zn²⁺ deposition in the Zn 002 plane and cooperate with SFPAM to resist water molecules for side reaction and dendrite inhibition. Consequently, the SFPAM-Zr hydrogel electrolyte confers a symmetrical Zn battery with stable reversibility and a high depth of discharge (DOD) of 57%. The Zn/active carbon (AC) capacitor can remain stable for 40 000 cycles with a capacity retention of 99%, and the Zn/PANI battery can deliver long-term cycling at different temperatures.