Highly polar CoP/Co2P heterojunction composite as efficient cathode electrocatalyst for Li-air battery

In order to advance the commercialization of rechargeable Li-air batteries, it is of importance to explore cathode catalyst with efficient catalytic activity. Transition metal oxides have poor electrical conductivity, while cobalt phosphide has excellent electrical conductivity and large specific surface area. Nevertheless, its application in organic Li-air batteries has been much less studied, and the electrocatalytic activity desires to be further elevated. Here, CoP/Co2P heterojunction composite with higher polarity was fabricated. The discharge product of high-polarity CoP/Co2P had a new porous box-like morphology, which was easy to be decomposed and exposed more active sites. The highly polar CoP/Co2P heterostructure composite had homogeneous pores, the synergistic effect existed between CoP and Co2P, and the discharge product was porous box mixed with Li2O2 and LiOH, which made CoP/Co2P achieve high specific capacity of 14632 mAh/g and cycle stably 161 times when used as air electrode cathode catalyst. This work furnished a thought for the construction of cathode catalysts with efficient catalytic activity for Li-air batteries.