Modulated FeWO <sub>4</sub> electronic structure via P doping on nitrogen‐doped porous carbon for improved oxygen reduction activity in zinc–air batteries
Yue Gong, Daijie Deng, Huan Wang, Jianchun Wu, Linhua Zhu, Cheng Yan, Henan Li, Li Xu
Abstract
Abstract As a catalyst of the air cathode in zinc–air batteries, tungstic acid ferrous (FeWO 4 ), a nanoscale transition metal tungstate, shows a broad application prospect in the oxygen reduction reaction (ORR). While FeWO 4 possesses favorable electrochemical properties and thermodynamic stability, its intrinsic semiconductor characteristics result in a relatively slow electron transfer rate, limiting the ORR catalytic activity. In this work, the electronic structure of FeWO 4 is significantly modulated by introducing phosphorus (P) atoms with abundant valence electrons. The P doping can adjust the electronic structure of FeWO 4 and then optimize oxygen‐containing intermediates' absorption/desorption efficiency to achieve improved ORR activity. Furthermore, the sodium chloride template is utilized to construct a porous carbon framework for anchoring phosphorus‐doped iron tungstate (P–FeWO 4 /PNC). The porous carbon skeleton provides numerous active sites for the absorption/desorption and redox reactions on the P–FeWO 4 /PNC surface and serves as mass transport channels for reactants and intermediates. The P–FeWO 4 /PNC demonstrates ORR performance ( E 1/2 = 0.86 V vs. RHE). Furthermore, the zinc–air batteries incorporating the P–FeWO 4 /PNC composite demonstrate an increased peak power density (172.2 mW·cm −2 ), high specific capacity (810.1 mAh·g −1 ), and sustained long‐term cycling stability lasting up to 240 h. This research not only contributes to the advancement of cost‐effective tungsten‐based non‐precious metallic ORR catalysts, but also guides their utilization in zinc–air batteries.