【摘要】 以LiOH·H2O、NH4VO3、NH4H2PO4和葡萄糖为原料,采用水热法制备碳包覆的磷酸钒锂化合物,利用XRD、SEM、TEM、恒流充放电测试、交流阻抗测试等手段,对产物的结构、形貌和电化学性能进行表征,研究了碳含量对材料电化学性能的影响。结果表明,在750℃焙烧的样品为单一纯相的单斜晶体结构,颗粒大小约1μm,分散性良好,且在颗粒表面包覆了一层无定形碳。在倍率0.1 C的电流密度下,在3.0~4.8 V电压范围内,碳含量为10.63%的样品首次放电容量达到163.6 m Ah/g;循环50次后,放电容量仍为156.5 m Ah/g,容量保持率为95.7%。更多还原

【Abstract】 A carbon-coated Li3V2( PO4)3/ C was synthesized by a hydrothermal route. In this route,Li OH·H2O,NH4VO3,NH4H2PO4 and glucose were selected as starting materials to prepare sample. The structure and electrochemical properties of the LVP / C were characterized by X-ray diffraction,scanning and transmission electron microscopy,galvanostatic charge-discharge cycling,and electrochemical impedance spectra. The influence of carbon content on electrochemical performance of Li3V2( PO4)3/ C was discussed. Experiment results show that,the sample roasted at 750 ℃ is a pure phase with monoclinic crystal structure,the particle size is about 1um,and has good dispersibility. Moreover,a layer of amorphous carbon is coated on the surface of the particles. The sample with10. 63% carbon content exhibits highest initial discharge capacity of 163. 6m Ah / g at 0. 1 C between 3. 0 and 4. 8 V.And the sample exhibits discharge capacity of 156. 5m Ah / g with capacity retention ratio of 95. 7% after 50 cycles.更多还原