【摘要】 通过水热法合成了纯度较高、结晶良好且粒径均匀细小的LiFePO4粉体.采用XRD,SEM对材料的结构和形貌进行分析,并研究了水热合成温度和反应时间对材料电化学性能的影响.结果表明,提高反应温度和延长合成时间有利于提高材料的结晶度,但会增大材料粒径.200℃水热合成5 h样品电化学性能最佳,0.1C倍率首次放电比容量138.0 mAh.g-1,具备工业化实用性.在水热合成中加入抗坏血酸和葡萄糖可有效避免Fe2+的氧化并增强材料的导电性.更多还原

【Abstract】 High-purity and well-crystallized LiFePO4 powders with uniformly distributed fine particles were synthesized in a direct hydrothermal reaction.The microstructure and morphology of the samples were characterized via XRD,SEM and constant current charge-discharge cycle test so as to investigate the influences of hydrothermal temperature/time on the electrochemical properties of as-prepared LiFePO4 powder.The results showed that increasing hydrothermal temperature/time benefits the improvement of crystallinity but coarsens the particles.The best electrochemical properties of the LiFePO4 hydrothermally synthesized are found at 200 ℃/5 hr with a specific capacity 138.0 mA·h·g-1 at 0.1C rate during initial discharging.It means that the hydrothermal synthesis is commercially practical.Moreover,adding the ascorbic acid and glucose in the hydrothermal synthesis can avoid efficiently the oxidation of Fe2+,thus enhancing the electric conductivity of LiFePO4 powder.更多还原