Highly dispersed Fe-doped CoP nanoparticles encapsulated with P, N co-doped hollow carbon shell toward robust bifunctional oxygen electrocatalysis and rechargeable Li–O2 batteries

Abstract

Engineering morphology and doping heteroatom are regarded as effective strategies for boosting the electrocatalytic performances of the transition-metal phosphides (TMPs). Herein, an efficient bifunctional electrocatalyst, the hollow core-shell nanostructured Fe–CoP@DPA composite consisting of Fe–CoP nanoparticles confined in a dopamine-derived carbon shell was synthesized through a one-step direct phosphorization method. With the merits of the unique hollow structure and efficient synergistic catalytic effect, the Fe–CoP@DPA delivers superior bifunctional ORR/OER activity. Density functional theory (DFT) calculation illustrates that Fe doping can upshift the d-band center of Fe–CoP@DPA, thereby enhancing the adsorption of intermediates during catalysis. The Li–O2 batteries with well-designed Fe–CoP@DPA cathode display an excellent long cycling stability of 282 cycles with a fixed capacity of 500 mAh g−1 at 200 mA g−1 and a high discharge specific capacity of 18208.5 mAh g−1 at 100 mA g−1. Rational designing the hollow nanostructured electrocatalyst with heteroatom doping will inspire the development of advanced cathode in Li–O2 batteries.