An Electrostripping Strategy for Constructing a 3D Honeycomb-Like Zn Anode Toward Dendrite-Free Zinc-Ion Batteries

The severe dendrite issue of the Zn anode greatly hinders the practical application of aqueous zinc-ion batteries, which demands a prompt solution. This work proposes an electrostripping strategy using sodium citrate (SC) solution as the electrolyte to fabricate a 3D honeycomb-like Zn (3DH-Zn) anode. Theoretical calculations and experimental results reveal that SC preferentially adsorbs on the Zn(100) and Zn(101) planes and exhibits a shielding effect, leading to the major dissolution of Zn atoms from the Zn(002) plane, thus obtaining a honeycomb-like structure. Notably, convinced by morphology characterization and finite element simulation results, Zn2+ tends to deposit on the lateral sides of the hexagonal holes on the 3DH-Zn anode, resulting in a flat deposition morphology dominated by Zn(101)/Zn(100) planes, which significantly inhibits dendrite formation. As a result, the 3DH-Zn symmetric cell achieves an ultra-long lifespan of 2000 h at 5.0 mA cm-2 and 1.0 mAh cm-2. Besides, the 3DH-Zn||VO2 full cell works for 1000 cycles at 1.0 A g-1 with a residual capacity of 123.1 mAh g-1. This work opens up a new horizon for applying electrostripping strategy in designing advanced Zn anode. On bare Zn anode, Zn2+ is reduced on some protrusions, which induces uneven nucleation and later dendrite formation. After electrostripping in sodium citrate solution, a 3D honeycomb-like Zn (3DH-Zn) anode with evenly distributed hexagonal holes is obtained. Due to the 3D honeycomb-like structure, Zn2+ would deposit evenly and form a flat surface on the 3DH-Zn anode, inhibiting dendrite formation. image