Toward High-Performance Zn Anodes: A Synergistic Dual-Ion Strategy via Interfacial Orientation Optimization

Abstract

Aqueous zinc metal batteries (AZMBs) demonstrate compelling advantages of low cost, high safety, and environmental benignity, rendering them promising candidates for next-generation energy storage systems. However, their commercialization is impeded by irreversible Zn anode issues, including dendrite growth, interfacial corrosion, and parasitic side reactions. This work introduces sodium tartrate (NTA) as a dual-ion additive that mitigates these challenges via cationic (Na+) electrostatic shielding and anionic (TA2−) acceleration of [Zn(H2O)6]2+ desolvation, guiding uniform (002)-oriented Zn deposition. Such a deposition orientation facilitates the uniform nucleation of Zn2+ on the Zn anode. Leveraging the synergistic adsorption protection of Na+ and TA2−, this mechanism ultimately enables a highly reversible Zn anode. Results confirm the Zn symmetric cell with modified electrolyte achieves stable reversible Zn plating/stripping for over 3000 h at 6.0 mA cm−2/1.0 mAh cm−2. Moreover, the Zn||Cu asymmetric cell exhibits exceptional cycling stability, delivering an average coulombic efficiency (CE) of 99.81% over 2900 cycles at 1.0 mA cm−2/0.5 mAh cm−2 and 99.82% over 3000 cycles at 5.0 mA cm−2/1.0 mAh cm−2. The NTA additive also demonstrates outstanding electrochemical compatibility in both Zn||α-MnO2 and Zn||I2 full cells. Notably, the Zn||I2 full cell maintains a high capacity retention of 93.29% after 10 000 cycles at 5.0 A g−1, highlighting its practical potential.