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Hollow graphene spheres are successfully prepared and employed as the separator coating materials for lithium-sulfur batteries. The hollow graphene spheres coated separator has been proven an efficient trap to adsorb and block polysulfide, greatly alleviating the shuttle effect. In the case of using elemental sulfur as cathode active material and the weight of the diaphragm is only increased by 10.3%, the lithium-sulfur battery with hollow graphene spheres coated separator delivers a high initial specific capacity of 1172.3 mAh g−1 at the current density of 0.2 C, and the discharge capacity remains at 829.6 mAh g−1 after 200 cycles with a capacity decay of 0.146% per cycle, showing excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

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–O 2 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–O 2 batteries. • The hollow nanostructured Fe–CoP@DPA was prepared through a facile phosphorization strategy. • The Fe–CoP@DPA catalyst exhibited excellent bifunctional electrocatalytic activity. • The Fe–CoP@DPA cathode showed a high specific capacity of 18208.5 mAh g−1 at 100 mA g−1. [ABSTRACT FROM AUTHOR]