A Generic "Engraving in Aprotic Medium" Strategy toward Stabilized Zn Anodes

Zn foil pretreatment is a direct route to alleviating Zn anode instability and maintaining high energy performance in Zn metal batteries. Unfortunately, prevailing methods for achieving an ideal Zn surface texture do not enable durable operation under a large depth of discharge, thus impairing the Zn utilization ratio. Zn etching is a more feasible way to control the surface texture, but this approach remains relatively unexplored. In this study, a general strategy is reported for Zn foil engraving in aprotic media to realize efficient anode pretreatment in terms of stability. These tests are performed using high-valence metal ions (especially Mo5+) in an aprotic environment as the key etchant to render a homogenously-distributed, 3D porous architecture on the Zn foil surface. Comprehensive experimental results and theoretical simulations revealed enhanced Zn nucleation and growth. This specially designed electrode exhibited a long lifespan with a large depth of discharge of 88% in symmetric cells. When assembled with a ZnxV2O5 cathode, the constructed cell demonstrated nearly full capacity retention even under stringent conditions (e.g., an N/P capacity ratio of 5.5). This study demonstrates the potential of a Zn etching pretreatment to address the prototypical instability issues of Zn anodes.