Zinc/Nickel-Doped Hollow Core-Shell Co₃ O₄ Derived from a Metal-Organic Framework with High Capacity, Stability, and Rate Performance in Lithium/Sodium-Ion Batteries

Transition-metal oxides are one of the most promising anode materials for energy storage in lithium- and sodium-ion batteries (LIBs and NIBs, respectively). To improve the electrochemical performance of metal oxides (e.g., Co₃ O₄ ), such as capacity and cyclability, a convenient strategy (with a metal-organic framework as a template) is introduced to generate Zn- or Ni-doped Co₃ O₄ . The obtained hollow core-shell nanosized Co₃ O₄ (denoted as Zn/Ni-Co-Oxide) derived from pyrolyzing zinc or nickel co-doped ZIF-67 (Co(mIm)₂ ; mIm=methylimidazole) shows a drastically enhanced capacity of 1300 mAh g^-1 at a high current density of 5000 mA g^-1 , compared with that of pristine cobalt oxide (800 mAh g^-1 ) in LIBs. A zinc-doped Zn-Co-Oxide demonstrates a stable capacity of 1600 mAh g^-1 at 1000 mA g^-1 for 700 cycles and an excellent performance in full coin cells (cycled with LiNi_0.5 Co_0.3 Mn_0.2 O₂ ). Moreover, NIB tests show a stable capacity of 300 mAh g^-1 for more than 250 cycles.