Effect of Spherical Particle Size on the Electrochemical Properties of Lithium Iron Phosphate  

作　　者：LIU Yuanyuan LIANG Guangchuan 刘远远;LIU Hao;ZHAO Xinxin;WANG Li;梁广川(Institute of Power Source and Ecomaterials Science,Hebei University of Technology,Tianjin 300130,China;Key Laboratory of Special Functional Materialsf or Ecological Environment and Information,Ministry of Education,Tianjin300130,China;Key Laboratory for New Type of Functional Materials in Hebei Province,Hebei University of Technology,Tianjin300130,China)

机构地区：[1]Institute of Power Source and Ecomaterials Science,Hebei University of Technology,Tianjin 300130,China [2]Key Laboratory of Special Functional Materialsf or Ecological Environment and Information,Ministry of Education,Tianjin300130,China [3]Key Laboratory for New Type of Functional Materials in Hebei Province,Hebei University of Technology,Tianjin300130,China

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2019年第3期549-557,共9页武汉理工大学学报（材料科学英文版）

摘　　要：The effect of spherical particle size on the surface morphology, electrochemical property and processability of lithium iron phosphate was systematically studied. Spherical lithium iron phosphate with different particle size distributions controlled with ball time of precursor slurry was prepared by spray drying method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), charge and discharge measurements and EIS. The electrochemical performances of the sample materials were measured by coin cells and 14500 batteries. XRD shows that the spherical lithium iron phosphate with different particle sizes all have good crystal structure due to the perfect mixing of the raw materials and rapid drying. The lithium iron phosphate microsphere with different particle sizes self-assembled with submicron primary particles has a core-shell structure. The longer ball time the precursors are, the smaller the active material particles are prepared. The electrode material with 6 h ball time of precursor slurry has the best physical properties and the processability. The composite has a uniform particle size and higher tap density of 1.46 g/cm3, which delivers a discharge capacity of 167.6 mAh/g at a discharge rate of 0.5 C. The results were confirmed by the 14 500 mA h cylindrical batteries, which delivers a discharge capacity of 579 mAh at 0.5 C. And low-temperature performance with capacity of 458.5 mA h at -20 °C under a discharge rate of 0.5 C is the 79.2% of the same discharge rate at 25 °C. Otherwise, the 14500 batteries also exhibit excellent cycling performance and the capacity maintains 93% after 2 000 cycles.The effect of spherical particle size on the surface morphology, electrochemical property and processability of lithium iron phosphate was systematically studied. Spherical lithium iron phosphate with different particle size distributions controlled with ball time of precursor slurry was prepared by spray drying method. The samples were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), charge and discharge measurements and EIS. The electrochemical performances of the sample materials were measured by coin cells and 14500 batteries. XRD shows that the spherical lithium iron phosphate with different particle sizes all have good crystal structure due to the perfect mixing of the raw materials and rapid drying. The lithium iron phosphate microsphere with different particle sizes self-assembled with submicron primary particles has a core-shell structure. The longer ball time the precursors are, the smaller the active material particles are prepared. The electrode material with 6 h ball time of precursor slurry has the best physical properties and the processability. The composite has a uniform particle size and higher tap density of 1.46 g/cm^3, which delivers a discharge capacity of 167.6 mAh/g at a discharge rate of 0.5 C. The results were confirmed by the 14 500 mA·h cylindrical batteries, which delivers a discharge capacity of 579 mAh at 0.5 C. And low-temperature performance with capacity of 458.5 mA h at -20?C under a discharge rate of 0.5 C is the 79.2% of the same discharge rate at 25 ?C. Otherwise, the 14500 batteries also exhibit excellent cycling performance and the capacity maintains 93% after 2 000 cycles.

关 键 词：LITHIUM ion BATTERY micro-spherical structure particle size SPRAY DRYING 

分 类 号：TB[一般工业技术]