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
Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The struc...Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The structure and morphology of the coating materials were investigated by XRD, SEM and TEM. The electrochemical performances of uncoated and Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials were studied within a voltage window of 3.00?4.35 V at current density of 30 mA/g. SEM, TEM and EDS analytical results indicate that the surface of LiNi1/3Mn1/3Co1/3O2 particles is coated with very fine Al2O3 composite, which leads to the improved cycle ability though a slight decrease in the first discharge capacity is observed. It is proposed that surface treatment by solid state reaction at room temperature is a simple and effective method to improve the cycle performance of LiNi1/3Co1/3Mn1/3O2 particles.展开更多
Treatment of iodide bridged dimer 4[Mo2O2S6Cu6I4Br2] 1 with 3, 5 bimethylpyridine or with K in CH3CN afforded the tetranuclear cluster [MoOS3Cu3I(3, 5 diMePy)4]·CH3CN 2 and dodecanuclear cluster (Et4N)4[Mo4Cu8O4S...Treatment of iodide bridged dimer 4[Mo2O2S6Cu6I4Br2] 1 with 3, 5 bimethylpyridine or with K in CH3CN afforded the tetranuclear cluster [MoOS3Cu3I(3, 5 diMePy)4]·CH3CN 2 and dodecanuclear cluster (Et4N)4[Mo4Cu8O4S12{(Ph2PS)2N}4] 3. Monomeric 2 possess a nest shaped skeleton. The structure of oligomeric 3 can be regarded as a tetramer of nest shaped MoCu3OS3 groups co polymerized by sharing the limbic Cu atoms.展开更多
Solid state reaction between La (Ac)3·3/2H2O and 8-hydroxyquinoline (Oxine)was studied at a low heating temperature. La (Oxine)3 was synthesized by one step solid state reaction at 60℃, and the product is charac...Solid state reaction between La (Ac)3·3/2H2O and 8-hydroxyquinoline (Oxine)was studied at a low heating temperature. La (Oxine)3 was synthesized by one step solid state reaction at 60℃, and the product is characterized by elementary analysis, IR, XRD,photoacoustic spectra and flourenscence spectra. The influence of the temperature on solid state reaction was discussed.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.
基金Project(50604018) supported by the National Natural Science Foundation of China
文摘Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The structure and morphology of the coating materials were investigated by XRD, SEM and TEM. The electrochemical performances of uncoated and Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials were studied within a voltage window of 3.00?4.35 V at current density of 30 mA/g. SEM, TEM and EDS analytical results indicate that the surface of LiNi1/3Mn1/3Co1/3O2 particles is coated with very fine Al2O3 composite, which leads to the improved cycle ability though a slight decrease in the first discharge capacity is observed. It is proposed that surface treatment by solid state reaction at room temperature is a simple and effective method to improve the cycle performance of LiNi1/3Co1/3Mn1/3O2 particles.
文摘Treatment of iodide bridged dimer 4[Mo2O2S6Cu6I4Br2] 1 with 3, 5 bimethylpyridine or with K in CH3CN afforded the tetranuclear cluster [MoOS3Cu3I(3, 5 diMePy)4]·CH3CN 2 and dodecanuclear cluster (Et4N)4[Mo4Cu8O4S12{(Ph2PS)2N}4] 3. Monomeric 2 possess a nest shaped skeleton. The structure of oligomeric 3 can be regarded as a tetramer of nest shaped MoCu3OS3 groups co polymerized by sharing the limbic Cu atoms.
文摘Solid state reaction between La (Ac)3·3/2H2O and 8-hydroxyquinoline (Oxine)was studied at a low heating temperature. La (Oxine)3 was synthesized by one step solid state reaction at 60℃, and the product is characterized by elementary analysis, IR, XRD,photoacoustic spectra and flourenscence spectra. The influence of the temperature on solid state reaction was discussed.
