Synthesis and characterization of cathode materials for high energy density and high rate capability lithium-ion rechargeable batteries .

摘要

Lithium metal oxides are of special interest as cathode materials in rechargeable lithium-ion batteries, because of their inherent property of Li deintercalation/intercalation upon charging and discharging, without altering the main crystal structure. We have developed a novel solution-based route for the synthesis of LiMn1.5 Ni0.5-xCrxO 4 (x = 0.1 and 0.2) cathode materials. The cathode powders were annealed at 875°C for 24 hrs in O2. The synthesized materials were structurally characterized using X-ray diffraction, Scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS). The coin cells were fabricated for the electrochemical characterization of the cathode material. The coin cells were fabricated inside a Glove Box in an inert atmosphere using LiMn1.5 Ni0.5-xCrxO 4 cathode, LiPF6[dissolved in ethyl carbonate (EC) and dimethyl carbonate (DMC) in 1:1 wt ratio) as electrolyte and Li foil as anode. The electrochemical studies include cyclic voltammetry and charge-discharge behavior, carried out at various current 'C' rates. The obtained data for LiMn1.5Ni0.4Cr0.1O4 and LiMn 1.5 Ni0.3Cr0.2O4 cathode materials were compared with the data obtained earlier for LiMn2O4 and LiMn1.5Ni0.5O4 cathode materials. It was found that LiMn1.5Ni0.4Cr0.1O4 cathode material had improved electrochemical performance, which is discussed in detail in the following dissertation.