Can Carbon be Attractive Substrates for Zn Anodes in Aqueous Electrolytes under HER Disturbance?

ABSTRACT Substrate engineering offers a promising pathway to mitigate metal plating/stripping behaviors, among which carbon‐based architectures are particularly attractive. While over a thousand studies document carbon's efficacy in stabilizing non‐aqueous alkali metal anodes, only 14 focus on carbon substrates for Zn in static aqueous zinc metal batteries. This striking disparity arising from carbon's catalytic activity toward water splitting casts doubt on its utility. Here, by controlling surface hydrophilicity, nanostructural penetrability and interfacial affinity, we not only clarify carbon's viability for dense Zn plating via asynchronous homotopic competing hydrogen evolution reactions and a secondary micro‐sized interface, but also establish three foundational design principles for governing Zn deposition: 1) nanoscale water penetration dictates growth geometry; 2) interfacial affinity chemistry determines gas dynamics and byproduct formation; 3) temporal decoupling of HER and plating creates evolving active zones. These insights further endow unprecedented Zn reversibility under ultra‐demanding conditions on carbon substrates without suppressing HER (10 mA /10 mAh cm −2 , 99.9% CE, >3.5 Ah cm −2 cumulative capacity) and superior full‐cell cyclability under industrial conditions (2 mAh cm −2 , 14 mA cm −2 ). Our work provides a new conceptual framework for the use of carbon substrates in aqueous metal batteries, transforming a long‐perceived limitation into a design opportunity.