Synthesis And Electrochemical Performance Of LI₄TI₅O₁₂ And FSN-4/MN₃O₄ Anode Materials For Lithium-Ion Battery

Rechargeable Li-ion batteries (LIBs) are considered as the most dominant technology in the field of energy storage due to their high energy density, long cycle life and low self-discharge property. However, the practical application of LIBs is still hampered by the poor electrochemical performance of the electrode materials, such as the low specific capacity, poor cycling stability and rate capability. Therefore, in this paper, Li4Ti5O12 and FSN-4 are selected as research objects to explore the influences of preparation technology on electrochemical performance. The main contents and results are as follows:Spinel Li4Ti5O12 is a promising candidate of anode materials for lithium-ion power batteries due to its excellent cycle performance and rate capability. In these researches, Li4Ti5O12 was synthesized by solid state method and a study on influences of the Li/Ti ratio of raw materials, calcination temperature and reaction time were carried out in detail through test measures such as scanning electron microscopy (SEM, X-ray diffraction (XRD), cyclic voltammetry (CV), etc. The optimized conditions are the raw materials with the Li/Ti ratio of 0.84, calcination temperature of 800℃ and reaction time of 10 h. The sample prepared at this condition possesses well-distributed morphology, high phase purity and good electromechanical performance. At a current density of 30 mAg-1, the initial discharge capacity is 174 mAhg-1, and it remains about 160 mAhg-1 after 50 cycles, suggesting an excellent cycling stability. Even at a high current density of 1Ag-1, it can still deliver a high reversible capacity of 100 mAhg-1, and almost completely restore when the current density back to 30 mAg-1, implying the exciting rate capability.The FSN-4/Mn3O4 composite was synthesized from KMnO4 and FSN-4 by immersion method. We obtained Mn3O4 successfully by this method and found it uniformly distributed on the surface of FSN-4. The as-synthesized composite delivers an initial discharge capacity of 1400 mAhg-1 and retains about 700mAhg-1 after 50 cycles. Compared with pure FSN-4, the capacity of composite is obviously increased except poor rate performance, which is probably attributed to the volume change and agglomerate of Mn3O4 during charge-discharge progress.