Controllable CF4 Plasma In Situ Modification Strategy Enables Durable Zinc Metal Anode.

Abstract

Zn metal with high specific capacity and low redox potential is deemed to be an ideal anode material for aqueous zinc-ion batteries (ZIBs). However, the serious dendrite problems induced by the uneven deposition of zinc shorten the service life and hinder the development of ZIBs. According to the nucleation and growth mechanism, the charge distribution at the anode interface is the critical factor affecting the deposition morphology. Herein, CF4 plasma technology is applied for the first time to in situ modification of the Zn anode, and then, the uniform nanoscale ZnF2 particles are formed. Due to the excellent ionic conductivity and poor electronic conductivity of ZnF2, the ion and electron distribution at the anode interface is orderly regulated, thus guiding uniform and reversible deposition behavior and restraining the dendrite growth. As a result, the Zn@ZnF2-5 anode exhibits low nucleation overpotential (16 mV), long cycle life (2500 h at 1 mA cm-2 and 1 mA h cm-2), and excellent resistance to high current density (20 mA cm-2) and high discharge depth (16%). Meanwhile, the Zn@ZnF2-5|I2@AC full battery shows remarkable cycle stability (1000 cycles) with ∼10% discharge depth of the anode. The novel and practical CF4 plasma in situ modification strategy provides a new idea for the interface modification of zinc anode.