LiNi0.5Mn1.5O4 Nanorod Clusters as Cathode Material for High Energy and High Power Lithium-Ion Batteries

High tap density LiNi0.5Mn1.5O4 nanorod clusters composed of well-crystallined LiNi0.5Mn1.5O4 nanorods with diameter of about 150 nm and length of about 1 mu m were synthesized by a template method. beta-MnO2 nanorods synthesized by a hydrothermal method were used as the template. LiNi0.5Mn1.5O4 nanorod clusters were then synthesized by solid-state reaction of a mixture containing beta-MnO2 nanorods, nickel acetate, and lithium hydroxide. It is found that a preheat treatment and grinding of the precursor for the solid state reaction is critical to form pure phase ordered LiNi0.5Mn1.5O4 and the nanorod cluster structure. LiNi0.5Mn1.5O4 nanorod clusters can deliver charge and discharge capacities as high as 140.61 mA h g(-1) and 128.42 mA h g(-1), respectively, at a. 0.1 C rate between 3.0 and 4.9 V versus Li/Li+. Moreover, the nanorod clusters exhibit high power capability, maintaining capacities of 105.90 and 98.05 mA h g(-1) at 2 C and 5 C rates, respectively.