Complete hollow ZnFe ₂ O ₄ nanospheres with huge internal space synthesized by a simple solvothermal method as anode for lithium ion batteries

Complete hollow ZnFe ₂ O ₄ nanospheres with well crystallization and uniform dispersion were successfully synthesized via a facile solvothermal method. The obtained ZnFe ₂ O ₄ material displays a complete hollow sphere structure with a huge interspace diameter of 180 nm. When used as anodes for lithium ion battery, the as-prepared sample exhibits high initial discharge/charge capacities of 1321.4/976.8 mA h·g ⁻¹ at 100 mA·g ⁻¹ , with an initial Coulombic efficiency reaching as high as 73.9%. Surprisingly, the specific capacity of ZnFe ₂ O ₄ electrodes experiences a process of decrease in initial 20 cycles and stable increase in subsequent 100 cycles, with a considerable discharge capacity of 1101.3 mA h·g ⁻¹ at 200 mA·g ⁻¹ after 120 cycles. Even at a high rate of 1600 mA·g ⁻¹ , the capability for electrodes still maintains at 703.6 mA h·g ⁻¹ , much larger than traditional commercialized graphite anode (372 mA h·g ⁻¹ ). Such remarkable electrochemical properties of the only ZnFe ₂ O ₄ material are even superior than those complex and expensive ZnFe ₂ O ₄ -based composites reported previously. It is believed that zinc ferrite nanosphere material with high reversible capacity, favorable cycling stability and good rate capability holds promise for becoming an alternative anode of lithium-ion batteries.