Structural and electrochemical properties of Eu-doped LiCoO_2

摘要

LiCoO_2 is a versatile commercially available cathode electrode material for lithium-ion batteries. In an attempt to improve the performance of lithium batteries with enhanced safety, Eu- doped LiCoO_2 powder was synthesized using a combustion route method. X-ray diffraction analysis reveals the existence of layered structure with the space group R-3m of hexagonal systems for all compounds. The local structure estimated by resonance spectroscopy (Laser Raman and FTIR) was reported. Surface morphology of the synthesized materials was determined by scanning electron microscope and it was found that the cathode materials consisted of highly ordered single crystalline particles with hexagonal shape. X-ray photoelectron spectra (XPS), was used to investigate the elementary states of the system. The electrical conductivities of the samples were measured at room temperature by the two probe method. The electrical conductivities of Eu-doped LiCoO_2 system increased with Eu content. An excellent reversible capacity was observed for the composite cathode containing 5.0 mol % Eu, when 2016 type coin cells were cycled at 0.1 C rate. This has been ascribed to the improved electrical conductivity induced by Eu doping.