Metal-organic frameworks derived yolk-shell ZnO/NiO microspheres as high-performance anode materials for lithium-ion batteries

Smart design and rational fabrication of novel anode materials with high specific capacity and long cycling stability are of significant importance for high-performance lithium-ion batteries (LIBs). Herein, nanostructured ZnO/NiO microspheres with a nanorods-composed shell and a microsphere yolk were synthesized by a controlled calcination treatment of the bimetallic organic frameworks in air. The obtained yolk-shell ZnO/NiO microspheres are observed to have an average diameter of 2 μm with uniform microsphere morphology from field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Benefitting from the unique yolk-shell structure inherited from the bimetallic organic frameworks and the synergistic effect from ZnO and NiO, the as-prepared yolk-shell ZnO/NiO displays excellent lithium storage performance, including high specific capacity (1008.6 mAh g⁻¹ at 0.1 A g⁻¹ after 200 cycles), superior rate capability (437.1 mAh g⁻¹ at 2 A g⁻¹) and outstanding long-term cycling stability (592.4 mAh g⁻¹ at 0.5 A g⁻¹ after 1000 cycles), which demonstrates its promising potential as high-performance anode material for LIBs.