Magnetic Field Modulated Intrinsic Charge and Spin Ordering in Ferromagnetic Electrocatalysts for Rechargeable Zn-Air Battery

Magnetic field-enhanced electrocatalytic activity has recently emerged as an effective strategy for electrocatalytic reactions. However, modulating the electrical behavior and spin ordering in real-time using magnetic field during the electrocatalytic process remains challenging. Herein, based on the coexistence of room-temperature ferromagnetic and magnetoresistance (MR) properties in La1-xSrxMnO3, it demonstrates that in addition to spin polarization, the negative MR effect contributes significantly to the enhancement of the oxygen evolution reaction (OER) owing to the considerable MR value (-7.32% for La0.8Sr0.2MnO3 at 1.0 T). Accordingly, a lessened OER overpotential of approximate to 120 mV (at 10 mA cm-2) and a reduced charge-transfer resistance are observed in La0.8Sr0.2MnO3 under a magnetic field of 1.0 T. Additionally, the power density of self-assembled Zn-air battery (ZnAB) based on La0.8Sr0.2MnO3 improves by 5.9 times under 1.0 T. Calculation results reveal that spin alignment can induce more unoccupied electronic states near the Fermi level, decrease the energy level of the Mn d-band center, and significantly reduce the O* formation barrier to enhance the OER activity of Sr-doped LaMnO3. Thus, the in situ regulation of charge and spin ordering by magnetic field offers a deeper understanding for designing high-performance ZnABs. The real-time regulation of charge and spin ordering is significant for designing high-efficiency electrocatalysts. An external direct current magnetic field to in situ enhance electrocatalytic reactions is crucial. The oxygen evolution reaction (OER) overpotential and intrinsic conductivity of La1-xSrxMnO3 can be tuned by applying 1.0 T magnetic field, which is attributed to the large negative magnetoresistance and optimized OER energy barrier.image