Perpustakaan Digital ITB

Due to the increasing need for energy storage solutions, the demand for highperformance lithium-ion batteries (LIBs) is on the rise. High-voltage lithium-ion batteries (HVLIBs) are viewed as strong candidates for future applications because of their superior energy density. One potential cathode material for HVLIBs is Lithium Nickel Manganese Oxide (LiNi0.5Mn1.5O4, LNMO), which provides an operating voltage of approximately 4.7 V, a high theoretical specific capacity, and remarkable thermal stability. Nevertheless, LNMO encounters several challenges, particularly concerning mechanical degradation, capacity loss, and electrolyte breakdown. The mechanical degradation and capacity loss are mainly attributed to Jahn-Teller distortion. In this study, cathode materials Li1+xNi0.5Mn1.5O4 (where x = 0, 0.2, 0.4) were created using a modified sol-gel technique. The variation in lithium content was incorporated to mitigate the impact of Jahn-Teller Distortion. This adjustment in lithium was applied during the post-annealing phase to examine its influence on crystallinity, morphology, and electrochemical performance. Material characterization was performed through X-ray diffraction (XRD) to analyze the crystal structure and scanning electron microscopy (SEM) for examining morphology. The slurry for the LNMO cathode was formulated using a mixed slurry approach and then applied to an aluminum current collector. Evaluation of the electrochemical performance was carried out on CR2032 coin cells, which included electrochemical impedance spectroscopy (EIS), charge-discharge profiles, and cycling performance assessments. The experimental findings indicated that adding excess lithium had a significant effect on the structure, morphology, and electrochemical characteristics of LNMO. Characterization results revealed that the addition of lithium enhanced structural stability, with the I311/I400 ratio nearing the ideal value and increased crystallinity. Samples with excess lithium demonstrated enhanced electrochemical performance, showing reduced charge-transfer resistance and greater lithium-ion diffusivity. The optimal lithium addition in the sample Li1.2Ni0.5Mn1.5O4 yielded the best results, achieving a capacity retention of 95.52% after 100 cycles at 0.5C and a discharge capacity of 122.41 mAh/g. Additionally, all samples exhibited a quasi-singlecrystal morphology, which contributed to the enhancement of structural stability and electrochemical performance.