▎ 摘　　要

The large radius of Na+/K+ makes it difficult to maintain the structural stability of electrode materials during repeated Na+/K+ insertion/deintercalation, especially for anode materials with high-rate and long-life cycles. Herein, the yolk-shell hetero-structured Ni2P1-xSx/Ni with a porous carbon/graphene coating (YS Ni2P1-xSx/Ni@C/G) is synthesized and successfully applied in Na/K storage. The YS Ni2P1-xSx/Ni with the interior void space can alleviate the volume expansion and facilitate Na+/K+ diffusion during the charge/discharge cycles, while the embedded metallic Ni and wrapped conductive C/G layer can accelerate the fast charge transfer. Thus, the optimized anode (YS Ni2P0.75S0.25/Ni@C/G) delivers high reversible capacities of 553 and 435 mA h g(-1) after 1000 cycles at 2000 and 4000 mA g(-1) for Na+-half-cells, respectively, and a high energy density of 131 W h kg(-1) at a power density of 221 W kg(-1) for Na-ion capacitor full-cells. For the K+-half-cells, it exhibits an excellent rate capability (238 mA h g(-1) at 3200 mA g(-1)) and cycle life. Density functional theory (DFT) calculations reveal that the Ni2P decreases the ion diffusion energy barrier, the Ni9S8 and Ni2P-Ni9S8 interface have improved adsorption capacity for ions, and the metallic Ni optimizes the electronic structure, thus leading to excellent electrochemical performances.