Fe3C decorated wood-derived integral N-doped C cathode for rechargeable Li-O2 batteries

Herein, an integral Fe3C decorated wood-derived Fe, N co-doped carbon (N-wdC-MS) was developed via one-step pyrolysis of FeCl3/LiCl impregnated paulownia-wood and melamine, which can be directly used as Li-O2 battery cathode. This three-dimensional (3D) free-standing cathode inherited the aligned channels of wood, ensuring unimpeded O2/electrolyte supply. The etching effect of FeCl3/LiCl mixed molten salt enlarges the porous-structure of carbonized-wood, expanding three-phase boundary. Fe3C@NC aggregates evenly grew on the surface and channels of carbonized wood, which act as catalytic sites. Moreover, in aqueous solution, N-wdC-MS showed excellent oxygen reduction reaction/oxygen evolution reaction catalytic activity. With these advantages, the Li-O2 battery assembled with N-wdC-MS as cathode deliver a superhigh specific capacity of 50.28 mAh cm−2 at a current density of 0.1 mAcm−2, and the cycle-life can maintain 190 times. This low-cost and easily available wood-based electrode provides a new idea for designing and large-scale production for cathode of other Metal-Air/Metal-S batteries.