Structure, Overpotentials, and Durability in a Single Lineage of CO ₂ ‐Activated Carbons: Insights for Near‐Neutral Zn–Air Battery Cathodes

Zinc–air batteries (ZABs) with near‐neutral electrolytes are considered promising candidates for sustainable energy storage systems. However, their practical application is still constrained by relatively low energy efficiency and insufficient cycling stability. In this study, we systematically investigate a family of CO ₂ ‐activated carbons (AC) derived from a single phenolic‐resin precursor and evaluate how their morphology and structural defects influence their performance as cathode scaffolds for near‐neutral ZABs. By carefully controlling the activation degree, we demonstrate that a 75% burn‐off achieves an optimal combination of high surface area and reduced concentration of defective carbon, resulting in the highest round‐trip energy efficiency of ∼70% at 1 mA cm ⁻² and improved cycle life. A gentle‐to‐moderate burn‐off of the defective carbon sites enhances durability. Increasing the activation degree beyond this point boosts the power density up to 28 mW cm ⁻² through the development of a more favorable pore structure and particle morphology, while affecting cycling stability. Overall, these results reveal how key carbon structural parameters govern ZAB performance within a single, systematically tuned carbon platform and provide guidance for the targeted design of carbon cathodes for high‐performance near‐neutral ZABs.