Cobalt Modulation of Manganese Electronic States in Perovskite Fluoride via Co─F─Mn Bonding for Enhanced Oxygen Reduction Reaction

The development of cost‐effective and efficient electrocatalysts for the oxygen reduction reaction (ORR) is pivotal for advancing clean energy technologies such as fuel cells and metal–air batteries. Herein, we report a high‐performance ORR catalyst based on cobalt‐doped KMnF ₃ perovskite fluoride in situ grown on a three‐dimensional carbon nanotube (CNT) network (Co‐KMnF ₃ @CNT). The CNT matrix effectively suppresses the agglomeration of KMnF ₃ particles, enhances electrical conductivity, and increases the exposure of active sites. More importantly, the introduced Co dopant induces lattice distortion and modulates the electronic structure of the Mn active sites. The optimized Co‐KMnF ₃ @CNT exhibits remarkable ORR activity in alkaline media, with a half‐wave potential (E _1/2 ) of 0.84 V and a limiting current density of 5.65 mA cm ⁻² , rivaling the performance of commercial Pt/C. Furthermore, it demonstrates superior stability, showing only an 8 mV negative shift in E _1/2 after 5000 cycles, which outperforms the Pt/C catalyst (15 mV decay). This work demonstrates the promising potential of Co‐KMnF ₃ @CNT as a noble‐metal‐free electrocatalyst and the effectiveness of strategic cation doping in optimizing the catalytic performance of perovskite fluorides.