A series of Cu-doped LiNi 0.5 Mn 1.5-x Cu x O 4 (x=0, 0.03, 0.05, 0.10, 0.15) spinel samples have been successfully prepared using a modified low temperature solution combustion synthesis method. X-ray diffraction(XRD) and infrared spectroscopy(FT-IR) analysis are used to characterize the phase structure. Scanning electron microscopy(SEM) is used to observe the microstructure of the products. The electrochemical performance are studied by galvanostatic charge-discharge testing, cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS). No obvious sencondary phases were observed in XRD patterns of as-synthesized LiNi 0.5 Mn 1.5-x Cu x O 4 powders. The samples have a combination structure of ordered and disordered space group and the order degree increases with the increase of Cu doping content obtained from FT-IR spectra. The electrochemical performances show that although the specific capacity decreases with the Cu-doping content, the cycle-life both at room temperature and 55°C and the C-rate performance are remarkably improved. The factors of stable structure, grain refinement, better crystallinity and lower charge transfer resistance lead to the excellent performance of Cu-doped samples.

中文翻译：

---

Cu掺杂LiNi 0.5 Mn 1.5-x Cu x O 4 (x=0, 0.03, 0.05, 0.10, 0.15) 通过改进的低温溶液燃烧合成法制备的具有显着改善的电化学性能

采用改进的低温溶液燃烧合成法成功制备了一系列Cu掺杂的LiNi 0.5 Mn 1.5-x Cu x O 4 (x=0, 0.03, 0.05, 0.10, 0.15)尖晶石样品。X射线衍射(XRD)和红外光谱(FT-IR)分析用于表征相结构。扫描电子显微镜（SEM）用于观察产品的微观结构。通过恒电流充放电测试、循环伏安法(CV)和电化学阻抗谱(EIS)研究其电化学性能。在合成的 LiNi 0.5 Mn 1.5-x Cu x O 4 粉末的 XRD 图中没有观察到明显的副相。从FT-IR光谱得到的样品具有有序和无序空间群的组合结构，有序度随着Cu掺杂量的增加而增加。电化学性能表明，虽然比容量随着Cu掺杂量的增加而降低，但室温和55℃下的循环寿命和C-rate性能均显着提高。稳定的结构、晶粒细化、更好的结晶度和较低的电荷转移电阻等因素导致了 Cu 掺杂样品的优异性能。