ABSTRACT
Aqueous zinc-ion batteries have attracted widespread attention due to their low cost and high safety. Unfortunately, their commercial applications are greatly inhibited by the negative effects of zinc dendrites and side reactions. A solution that utilizes a 3D host can help mitigate these issues. In this paper, we present a 3D host that is composed of an aerogel scaffold with a poly(vinyl alcohol) and MXene structure. The embedded Zn can be densely packed inside the host due to its zincophilic properties. During cycling, the fluorine-based functional groups on the surface of MXene were able to react with the electrolyte to form the ZnF2 solid electrolyte interphase, which can effectively protect the composite anode. As a result, the symmetrical battery was capable of stable cycling for >300 h at a high current density of 10 mA cm-2. More impressively, the assembled full cell retained 93.86% after 800 cycles at a current density of 5 A g-1. This work provides an effective idea for improving the cycling performance of aqueous zinc-ion batteries.
ABSTRACT
Zn electrodeposition mechanism is a cornerstone of dendritic issue exploration in Zn-ion battery. Investigation of the inherent early-stage Zn plating kinetics and its dependence on the reactivity of anode-electrolyte interphase is crucial. Herein, the kinetic evolution of Zn plating on three characteristic substrates is quantified: fresh Zn, commercial Zn foil, and Zn foil with spontaneously generated solid-electrolyte interphase (SEI). Using scanning electrochemical microscopy analysis, the original interphase regulation of Zn deposit orientation and the competitive reaction between Zn deposition and SEI passivation are studied in situ. Furthermore, the SEI layer can suppress the dendrite growth at initial state by guiding the horizontal alignment of Zn flakes and promote Zn plating process. This approach provided a feasible consideration into interphase engineering of various metal anodes.
