Developing highly active and low cost catalysts for Li-O-2 batteries is essential to realize their practical application as power sources. In this study, nickel phosphide (Ni2P) particles were synthesized from commercial Ni(OH)(2) via a facile process, their electrochemical performance as cathode catalyst of Li-O-2 batteries was evaluated and excellent capability of catalyzing ORR/OER has been demonstrated. The battery with it delivers greatly improved performance than that without catalyst in a wide rang of working current density, judging from the capacity, discharge/charge overpotential, round-trip efficiency and cycling stability. These outstanding results may suggest tremendous application potential of metal phosphides in Li-O-2 batteries as cathode catalysts. (c) 2018 The Electrochemical Society.