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.