Using low-cost FePO4·2H2O as iron source,Na2FePO4F/C composite is prepared by alcohol-assisted ball milling and solid-state reaction method.The XRD pattern of Na2FePO4F/C composite demonstrates sharp peaks,indica...Using low-cost FePO4·2H2O as iron source,Na2FePO4F/C composite is prepared by alcohol-assisted ball milling and solid-state reaction method.The XRD pattern of Na2FePO4F/C composite demonstrates sharp peaks,indicating high crystalline and phase purity.The SEM and TEM images reveal that diameter of the spherical-like Na2FePO4F/C particles ranges from 50 to 300 nm,and HRTEM image shows that the surface of Na2FePO4F/C composite is uniformly coated by carbon layer with a average thickness of about 3.6 nm.The carbon coating constrains the growth of the particles and effectively reduces the agglomeration of nanoparticles.Using lithium metal as anode,the composite delivers a discharge capacities of 102.8,96.4 and 90.3 mA·h/g at rates of 0.5C,1C and 2C,respectively.After 100 cycles at 0.5C,a discharge capacity of 98.9 mA·h/g is maintained with capacity retention of 96.2%.The Li+diffusion coefficient(D)of Na2FePO4F/C composite is calculated as 1.71×10^–9 cm^2/s.This study reveals that the simple solid state reaction could be a practical and effective synthetic route for the industrial production of Na2FePO4F/C material.展开更多
基金Projects(51472211,51502256)supported by the National Natural Science Foundation of ChinaProjects(2016GK4005,2016GK4030)supported by the Strategic New Industry of Hunan Province,ChinaProject(13C925)supported by the Research Foundation of Education Bureau of Hunan Province,China
文摘Using low-cost FePO4·2H2O as iron source,Na2FePO4F/C composite is prepared by alcohol-assisted ball milling and solid-state reaction method.The XRD pattern of Na2FePO4F/C composite demonstrates sharp peaks,indicating high crystalline and phase purity.The SEM and TEM images reveal that diameter of the spherical-like Na2FePO4F/C particles ranges from 50 to 300 nm,and HRTEM image shows that the surface of Na2FePO4F/C composite is uniformly coated by carbon layer with a average thickness of about 3.6 nm.The carbon coating constrains the growth of the particles and effectively reduces the agglomeration of nanoparticles.Using lithium metal as anode,the composite delivers a discharge capacities of 102.8,96.4 and 90.3 mA·h/g at rates of 0.5C,1C and 2C,respectively.After 100 cycles at 0.5C,a discharge capacity of 98.9 mA·h/g is maintained with capacity retention of 96.2%.The Li+diffusion coefficient(D)of Na2FePO4F/C composite is calculated as 1.71×10^–9 cm^2/s.This study reveals that the simple solid state reaction could be a practical and effective synthetic route for the industrial production of Na2FePO4F/C material.
