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

Engineering morphology and doping heteroatom are regarded as effective strategies for boosting the electro-catalytic performances of the transition-metal phosphides (TMPs). Herein, an efficient bifunctional electro-catalyst, 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.