α-Fe2O3 nanospindles as an efficient catalyst for optical and magnetic fields co-assisted Li-O2 cells

The photo-assisted lithium-oxygen (Li-O2) cell is widely concerned due to its low overpotential. However, rapid recombination rate of photogenerated electrons and holes remains a fundamental challenge for photo-assisted Li-O2 cells. Herein, we design an optical and magnetic fields co-assisted Li-O2 cell based on α-Fe2O3 nanospindles. We employed PL spectrum and I-t curve confirm that under the magnetic field, the photogenerated electrons and holes are driven via the opposite Lorentz forces in photo-assisted Li-O2 cells, which is beneficial to accelerating the formation and decomposition of Li2O2. The optical and magnetic fields co-assisted Li-O2 cell based on α-Fe2O3 nanospindles achieves an ultra-high discharge platform of 3.47 V and a low charge platform of 3.57 V, as well as a surprising energy efficiency of 97.2%. In addition, the optical and magnetic fields co-assisted Li-O2 cell can stably cycle for over 25 cycles. This study offers a reference for improving the electrochemical kinetics of photo-assisted Li-O2 cell by introducing magnetic field, which opens up a new avenue for the development of high-performance Li-O2 cells.