Selective exposure of Zn (002) plane via chemical etching and physical polishing for stable aqueous Zn-ion batteries

Dendrite growth on Zn anodes remains a major challenge that limits the performance and safety of aqueous Zn-ion batteries, and regulating the preferential growth of the Zn (002) crystal plane is regarded as an effective strategy to suppress dendrite formation. In this work, we propose a chemical etching–physical polishing (CEPP) synergistic strategy to achieve the selective exposure of specific crystal planes and interfacial structural regulation. Experimental results reveal that, during the chemical etching process, Sn 4 + preferentially reacts with the high-surface-energy Zn (101) planes through a substitution reaction, thereby reducing the overall surface free energy and gradually exposing the thermodynamically more stable and lower-surface-energy Zn (002) planes. Experimental results reveal that, during the chemical etching process, Sn 4+ preferentially reacts with the high-surface-energy Zn (101) planes through a substitution reaction, thereby reducing the overall surface free energy and gradually exposing the thermodynamically more stable and lower-surface-energy Zn (002) planes. Subsequently, physical polishing is employed to remove the loose Sn-rich surface layer, leaving behind a compact and strongly adherent Sn interfacial layer. The resulting Zn anode, integrating crystal-plane orientation control with enhanced interfacial stability, is denoted as Zn-CEPP. Benefiting from these structural advantages, the Zn-CEPP anode exhibits a low voltage hysteresis of only 28.0 mV and outstanding long-term cycling stability in symmetric cells, operating stably for over 3100 h at a current density of 1 mA cm⁻ 2 without short-circuit failure. Furthermore, the assembled Zn-CEPP||Zn x V 2 O 5 ·H 2 O (Zn-CEPP||ZVO) full cell maintains approximately 70.36% of its initial capacity after 1000 charge–discharge cycles at a high current density of 2 A g⁻ 1 . In summary, the CEPP surface-engineering strategy proposed in this work, through the synergistic integration of interfacial structural design and selective crystal-plane regulation, significantly enhances the controllability of Zn deposition and the cycling reversibility of Zn anodes, providing a simple and effective pathway toward highly stable aqueous Zn-ion batteries.