Lithium secondary batteries using LiNi0.5Mn1.5O4 films as a cathode material were prepared by pulsed laser deposition on stainless steel substrates. X-ray diffraction and Field-emission Scanning Electron Microscope results show that the film deposited at 750°C exhibits good crystallinity with well-defined grains structure. Charge/discharge behavior of the batteries under a high cutoff voltage of 4.9V vs. Li was highly improved by using Li-rich samples, which exhibits larger specific capacity and higher rate capability. Especially, when the substrate temperature increases to 750°C, the reversible capacity maintains 116.8mAhg−1 after 100 cycles at 0.5C, and the Coulombic efficiency is almost a constant value of 98%. It also exhibits excellent rate capability, as the rates increase to 5 and 10C, and about 95.4% and 92.3% of its initial capacity at 0.2C can be retained.