High power and capacity of LiNi_(0.5)Mn_(1.5)O_4 thin films cathodes prepared by pulsed laser deposition

摘要

Lithium secondary batteries using LiNi_(0.5)Mn_(1.5)O_4 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℃ exhibits good crystallinity with well-defined grains structure. Charge/discharge behavior of the batteries under a high cutoff voltage of 4.9 V 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℃, the reversible capacity maintains 116.8 mAh g~(-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.