Mn-N-P doped carbon spheres as an efficient oxygen reduction catalyst for high performance Zn-Air batteries

Low-cost and efficient oxygen reduction reaction(ORR)electrocatalysts are the key to developing Zn-air batteries for renewable energy storage.Herein,the Mn-N-P doped carbon sphere was prepared through polymerization of hexachlorotripolyphosphazene(HCCP)and phloroglucinol,and then followed the calcination at 900°C.Theory calculations demonstrated the introduction of Mn in N-P doped carbon could lower the dissociation barrier of O2into O*and promote the ORR through a 4e-pathway.The asprepared catalysts exhibited a half-wave potential of 0.82 V vs.RHE and limiting current density of 5.2 m A/cm^(2)toward ORR,which was comparable to those of the commercial Pt/C catalysts.In addition,Zn-air batteries with 0.05 Mn-N-P-C catalysts showed a high specific capacity of 830 m Ah/gZnand excellent cycle stability.This facile approach demonstrated herein could be a solution to develop optimum non-precious metal catalysts for the application in cathodes of proton exchange membrane fuel cells.This study also provides new insight to design the catalysts of multi-heteroatom coordinated metal in the carbon matrix for both fundamental researches and practical applications.