A high-performance electrocatalyst for oxygen reduction derived from copolymer-anchored polyoxometalates

The development and synthesis of cathode electrocatalysts with high activity and durable stability for metal-air batteries is an important challenge in the area of electrocatalysis. Herein, we introduce a novel in-situ nitriding and phosphating strategy for producing W₃N₄ and WP from phosphotungstic acid (HPW)-polyaniline-phytic acid-Fe³⁺ organic–inorganic hybrid material. The final material has a three-dimensional porous framework with W₃N₄-WP heterostructures embedded in the carbon matrix (W₃N₄-WP@NPC). As-made materials exhibit exceptional electrocatalytic performance for the oxygen reduction reaction (ORR), with a diffusion-limiting current density of 6.9 mA·cm⁻² and a half-wave potential of 0.82 V. As a Zn-air primary cathode, the W₃N₄-WP@NPC assembled battery can provide a relatively high peak power density (194.2 mW·cm⁻²). As a Zn-air secondary air-cathode, it has great cycling stability over 500 h. This work provides a simple and efficient method for rationally designing high-performance air cathodes from copolymer-anchored polyoxometalates.