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Abstract: Li3Mn1− x V x O4 (0≤ x ≤0.4) cathode materials were synthesized by the solid state method. The effect of the vanadium content on the structure, morphology and electrochemical properties of the samples was investigated. The samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements, respectively. The XRD patterns indicated that the doped samples showed similar phase structure with un-doped samples and the peaks of doped samples slightly shift towards a lower diffraction angle with increasing of vanadium content. The vanadium doping could reduce particle aggregation of Li3Mn1− x V x O4 samples. The Li3Mn1− x V x O4 (0< x ≤0.3) samples showed higher reversible capacity and better rate-capability compared to Li3MnO4. Electro-chemical impedance spectroscopy (EIS) measurements revealed that the improved electrochemical performances could be attributed to the lower solid electrolyte interfacial resistance and charge-transfer resistance due to appropriate amount of vanadium doping in Li3MnO4. [Copyright &y& Elsevier]

Abstract: Two kinds of spinel LiMn2O4 thin film for lithium ion micro-batteries were successfully prepared on polycrystal Pt substrates by spin coating methods, which were carried out under ultrasonic irradiation (USG) and magnetic stirring (MSG), respectively. The microstructures and electrochemical performance of LiMn2O4 thin films were characterized by thermogravimetry analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and galvanostatic charge–discharge measurements. It was found that the crystalline structure of USG samples grew better than that of the MSG samples. At the same time, higher discharge capacity and better cycle stability were obtained for the LiMn2O4 thin films of USG at the current density of 50μAh/cm2 between 3.0 and 4.3V. The 1st discharge capacity was 57.8μAh/cm2-μm for USG thin films and 51.7μAh/cm2-μm for MSG thin films. After 50cycles, 91.4% and 69% of discharge capacity could be retained respectively, indicating that ultrasonic irradiation condition during spin coating was more suitable for preparing spinel LiMn2O4 thin films with better electrode performance for lithium ion micro-batteries. [Copyright &y& Elsevier]

Abstract: LiNi0.5Mn0.5O2 thin films were successfully prepared by a sol–gel spin-coating method. SEM results revealed that the annealed films have a relatively smooth and dense surfaces, along with small grains with homogeneous distribution. The crystallinity and the grain size of thin films increase as the annealing temperature enhanced. The initial discharge capacity enhances from 13 to 46 μAh/cm2μm when the drying temperature increases from 700 to 800 °C. [Copyright &y& Elsevier]