Self-assembled hierarchical porous NiMn ₂ O ₄ microspheres as high performance Li-ion battery anodes

Hierarchical structured porous NiMn ₂ O ₄ microspheres assembled with nanorods are synthesized through a simple hydrothermal method followed by calcination in air. As anode materials for lithium ion batteries (LIBs), the NiMn ₂ O ₄ microspheres exhibit a high specific capacity. The initial discharge capacity is 1126 mA h g ^-1 . After 1000 cycles, the NiMn ₂ O ₄ demonstrates a reversible capacity of 900 mA h g ^-1 at a current density of 500 mA g ^-1 . In particular, the porous NiMn ₂ O ₄ microspheres still could deliver a remarkable discharge capacity of 490 mA h g ^-1 even at a high current density of 2 A g ^-1 , indicating their potential application in Li-ion batteries. This excellent electrochemical performance is ascribed to the unique hierarchical porous structure which can provide sufficient contact for the transfer of Li ⁺ ion and area for the volume change of the electrolyte leading to enhanced Li ⁺ mobility.