Boron-doped carbon microspheres as the catalyst for rechargeable Al-air batteries

Three-dimensional mesoporous boron-doped carbon microspheres (B-CMs) were synthesized through a facile impregnation-calcination method. The B atoms introduced plentiful defects into the surfaces of CMs and were mainly presented in the form of boron carbide, which increases the specific surface area of the composite material and endows it with enhanced catalytic activity. A rechargeable aluminum (Al-)-air battery with B-CMs catalysts exhibited low overpotentials and its effective discharge capacity reached 300 mAh g^?1 at the current density of 50?mA g^?1. The capacity of Al-air battery was maintained at 584 mAh g^?1 after 30 cycles.