General Approach for MOF-Derived Porous Spinel AFe₂O₄ Hollow Structures and Their Superior Lithium Storage Properties

A general and simple approach for large-scale synthesis of porous hollow spinel AFe₂O₄ nanoarchitectures via metal organic framework self-sacrificial template strategy is proposed. By employing this method, we can successfully synthesize uniform NiFe₂O₄, ZnFe₂O₄, and CoFe₂O₄ hollow architectures that are hierarchically assembled by nanoparticles. When these hollow microcubes were tested as anode for lithium ion batteries, good rate capability and long-term cycling stability can be achieved. For example, high specific capacities of 636, 449, and 380 mA h g^-1 were depicted by NiFe₂O₄, ZnFe₂O₄, and CoFe₂O₄, respectively, at a high current density of 8.0 A g^-1. NiFe₂O₄ exhibits high specific capacities of 841 and 447 mA h g^-1 during the 100th cycle when it was tested at current densities of 1.0 and 5.0 A g^-1, respectively. Discharge capacities of 390 and 290 mA h g^-1 were delivered by the ZnFe₂O₄ and CoFe₂O₄, respectively, during the 100th cycle at 5.0 A g^-1.