N/P Co-Doped Nanowrinkled Carbon Spheres Enabling Robust Metal-Free Cathodes for High-Performance Zinc-Air Batteries

Abstract The pursuit of productive and resilient metal-free electrocatalysts for the oxygen reduction reaction (ORR) is imperative for realizing advanced zinc-air battery (ZAB) technologies. Herein, we report a nanowrinkled nitrogen/phosphorus codoped carbon sphere (CNP) synthesized via an in situ heteroatom incorporation followed by a pyrolysis strategy. The resulting catalyst uniformly distributes N and P dopants, enabling optimized defect density and enhanced electronic modulation. XPS analysis reveals abundant pyridinic (17.96%) and pyrrolic nitrogen (52.97%) species as key active sites, which promote favorable oxygen adsorption and accelerate charge-transfer kinetics. When integrated into a liquid ZAB, the CNP cathode achieves a high peak power density of 202.2 mW cm–2 and a specific capacity of 768.8 mAhgZn−1, and flexible ZABs exhibit a peak power density of 67.5 mW cm–2 with steady output during mechanical deformation. This work reveals that synergistic N/P electronic regulation integrated with nanostructural design provides a viable route toward highly durable and efficient metal-free air cathodes.