Phspho-olivine Li Fe PO4 was synthesized from the relatively insoluble lithium source Li2CO3, proper iron and phosphorus sources(n(Li):n(Fe):n(P)=1:1:1) by a novel hydrothermal method. Afterwards, the optimal sample w...Phspho-olivine Li Fe PO4 was synthesized from the relatively insoluble lithium source Li2CO3, proper iron and phosphorus sources(n(Li):n(Fe):n(P)=1:1:1) by a novel hydrothermal method. Afterwards, the optimal sample was mixed with glucose and two-step calcinated(500 ℃ and 750 ℃) under high-purity N2 to obtain the Li Fe PO4/C composite. The resultant samples were characterized by X-ray diffraction(XRD), atomic absorption spectrometry(AAS), scanning electron microscops(SEM), transmission electron microscopy(TEM), energy dispersive spectrometry(EDS), elementary analysis(EA) and electrochemical tests. The results show that the optimal reaction condition is to set the reactant concentration at 0.5 mol·L-1, the reaction temperature at 180 ℃ for 16 h duration. During the reaction course, an intermediate product NH4 Fe PO4·H2O was first synthesized, and then it reacted with Li+ to form Li Fe PO4. The optimized Li Fe PO4 sample with an average particle size(300 to 500 nm) and regular morphology exhibits a relatively high discharge capacity of 84.95 m Ah· g-1 at the first charge-discharge cycle(0.1C, 1C=170 m A·g-1). Moreover, the prepared Li Fe PO4/C composite shows a high discharge capacity of 154.3 m Ah·g-1 at 0.1C and 128.2 m Ah·g-1 even at 5C. Besides it has good reversibility and stability in CV test.展开更多
基金Funded by the National Natural Science Foundation of China(No.51004074)
文摘Phspho-olivine Li Fe PO4 was synthesized from the relatively insoluble lithium source Li2CO3, proper iron and phosphorus sources(n(Li):n(Fe):n(P)=1:1:1) by a novel hydrothermal method. Afterwards, the optimal sample was mixed with glucose and two-step calcinated(500 ℃ and 750 ℃) under high-purity N2 to obtain the Li Fe PO4/C composite. The resultant samples were characterized by X-ray diffraction(XRD), atomic absorption spectrometry(AAS), scanning electron microscops(SEM), transmission electron microscopy(TEM), energy dispersive spectrometry(EDS), elementary analysis(EA) and electrochemical tests. The results show that the optimal reaction condition is to set the reactant concentration at 0.5 mol·L-1, the reaction temperature at 180 ℃ for 16 h duration. During the reaction course, an intermediate product NH4 Fe PO4·H2O was first synthesized, and then it reacted with Li+ to form Li Fe PO4. The optimized Li Fe PO4 sample with an average particle size(300 to 500 nm) and regular morphology exhibits a relatively high discharge capacity of 84.95 m Ah· g-1 at the first charge-discharge cycle(0.1C, 1C=170 m A·g-1). Moreover, the prepared Li Fe PO4/C composite shows a high discharge capacity of 154.3 m Ah·g-1 at 0.1C and 128.2 m Ah·g-1 even at 5C. Besides it has good reversibility and stability in CV test.
