Biomass-Derived Carbon Electrocatalysts for Zinc-Air Batteries: A Review of Design Strategies, Machine Learning Acceleration, and Future Perspectives

The practical application of rechargeable zinc-air batteries (R-ZABs) is critically limited by high-performance bifunctional oxygen electrocatalysts, as their intrinsic activity directly governs the efficiency and longevity of air cathodes. Recently, biomass-derived carbon materials are compelling candidates for bifunctional electrocatalysts, benefiting from their renewable nature, low cost, inherently porous architecture, and naturally doped heteroatoms. Understanding the structural design principles of biomass-derived carbon electrocatalysts is therefore essential for advancing the performance of R-ZABs. Based on this understanding, this review first introduces the fundamental configuration, reaction mechanisms, and challenges for R-ZABs to understand the cathodic catalyst design criteria. Furthermore, the diverse precursor sources of biomass materials are summarized and categorized. Moreover, the design strategies for biomass-derived carbon catalysts, including metal-free, single-atom, and transition-metal-compound decorations, as well as integrated air cathodes, are summarized to achieve high activity and long-term stability in R-ZABs. Notably, machine learning has gradually been applied to the high-throughput catalyst design and optimization due to its advantages in efficiently analyzing structure-performance relationships and accurately predicting catalytic activity. Finally, the critical challenges of biomass-derived carbon electrocatalysts, together with the future perspectives for R-ZABs, are thoroughly emphasized. This review aims to guide the development of biomass-derived carbon electrocatalysts for next-generation R-ZABs.