Nitrogen-doping carbon encapsulated hollow ZnSe/CoSe2 nanospheres as high performance anodes for lithium-ion batteries
Hierarchical nitrogen-doping carbon encapsulated hollow ZnSe/CoSe2 (ZnSe/CoSe2@N-C) nanospheres are fabricated by convenient solvothermal and selenization approach followed by one carbonization process. The as-obtained ZnSe/CoSe2@N-C possesses multilevel nanoscale architecture composed of thin carbon shell around 12 nm and hollow selenide nanoparticle as the core with tiny rough grains and rich voids as the subunits. The robust carbon protective shell and synergistic effect between double metal ions boost the electron and ion transportation as well as promote effective extraction and insertion of lithium ions. Hollow ZnSe/CoSe2@N-C spheres present high reversible capacity with 1153 mAh g-1 remained over 100 cycles at 100 mA g-1. In particular, hollow ZnSe/CoSe2@N-C spheres display an outstanding cycling stability at the high rate of 2000 mA g-1 with the reversible capacity of up to 966 mAh g-1 remained after 500 cycles. As an advanced anode, ZnSe/CoSe2@N-C composite shows remarkable cycling stability and exceptional rate capability in the field of energy storage technologies.