A Multifunctional Composite Interface Layer toward High-Performance Stable Zn Anode

Abstract

The development of aqueous zinc-ion batteries (AZIBs) is often limited by uncontrolled dendrite growth and detrimental side reactions occurring at the Zn anode. Herein, a multifunctional protective coating, constructed by incorporating vermiculite nanosheets (VN) into a carboxymethyl cellulose (CMC) matrix, was developed to mitigate these challenges. The VN-CMC composite coating exhibits a lamellar structure containing abundant polar groups such as hydroxyl (-OH) and carboxymethyl (-CH2COOH). The desolvation process of Zn2+ is expedited by these polar functional groups, which further direct the homogeneous plating of zinc onto the (002) crystal facet. Moreover, the lamellar architecture contributes to a homogeneous electric field distribution and modulates Zn2+ flux, thereby inhibiting dendrite nucleation and propagation. Consequently, the VN-CMC@Zn anode delivers exceptional long-term stability, sustaining up to 7100 h (at 0.5 mA cm-2, 1 mAh cm-2) and 3000 h (at 5 mA cm-2, 5 mAh cm-2). When assembled into a full battery with NaV3O8·1.5H2O (NVO) as the cathode, the composite-protected anode delivers remarkable cycling durability, retaining 90% of its initial capacity after 2000 cycles at 2 A g-1. This study offers a promising strategy for the rational engineering of highly reversible Zn metal anodes.