LiNi_0.5Mn_1.5O₄ thin films were coated on stainless steel substrates by radio-frequency sputtering at room temperature for a lithium-ion battery. The cathode films were post-annealed at 500, 600 and 700 °C to study (i) the impact of annealing temperature on the crystallization of the cathode film and (ii) the reactivity between the cathode film and the stainless steel substrate. X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy were adopted to characterize the thin films. The electrochemical properties of the LiNi_0.5Mn_1.5O₄ cathodes were investigated with cyclic voltammetry and galvanostatic charge/discharge tests. As the annealing temperature increased from 500 to 600 °C, the crystallinity and electrochemical characteristics of LiNi_0.5Mn_1.5O₄ both improved. However, as the annealing temperature further increased to 700 °C, the phase purity and the electrochemical performance were greatly deteriorated. Combined chemical analyses with time-of-flight secondary ion mass spectrometry depth profiling and energy-dispersive X-ray spectroscopy in scanning transmission electron microscopy mapping have indicated that the cross-diffusion of metal ions between LiNi_0.5Mn_1.5O₄ and the stainless steel substrate takes place at a temperature higher than 600 °C, which was attributed as a main origin of the phase change in the LiNi_0.5Mn_1.5O₄ cathode layer and electrochemistry degradations of lithium-ion battery.

在室温下通过射频溅射将LiNi _0.5 Mn _1.5 O ₄薄膜涂覆在不锈钢基板上，以用于锂离子电池。将阴极膜在500、600和700°C下进行后退火，以研究（i）退火温度对阴极膜结晶的影响，以及（ii）阴极膜与不锈钢基材之间的反应性。X射线衍射，扫描电子显微镜和X射线光电子能谱被用来表征薄膜。LiNi _0.5 Mn _1.5 O ₄的电化学性质用循环伏安法和恒电流充/放电试验研究了阴极。随着退火温度从500℃升高到600℃，LiNi _0.5 Mn _1.5 O ₄的结晶度和电化学特性均得到改善。然而，随着退火温度进一步升高至700℃，相纯度和电化学性能大大劣化。化学分析与飞行时间二次离子质谱深度分析以及能量色散X射线光谱在扫描透射电子显微镜图中的结合表明，LiNi _0.5 Mn _1.5 O ₄之间金属离子的交叉扩散不锈钢基材在高于600°C的温度下发生，这被认为是LiNi _0.5 Mn _1.5 O ₄阴极层中相变和锂离子电池电化学降解的主要原因。