模板法制备磷酸铁锂纳米颗粒的研究

Study on preparation of LiFePO nanoparticle by template method

以球孔碳为模板,通过一步法和两步法合成了纳米磷酸铁锂。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和扣电测试表征材料的性能。相比一步法,两步法合成的磷酸铁锂晶粒更小,各项电化学性能更好。结果显示:两步法磷酸铁锂的放电比容量在1C放电比容量为136mAh/g,循环后,比容量无明显衰减;而一步法磷酸铁锂1C放电比容量为108.9mAh/g,循环后比容量迅速衰减到100mAh/g以下。晶粒大小对于磷酸铁锂的电化学性能具有关键影响,而模板有利于控制磷酸铁锂纳米颗粒的形貌和尺寸。

The lithium iron phosphate(LiFePO_(4))nanoparticles were successfully synthesized by one-step method and two-step method respectively,using spherically porous carbon(3 DOM carbon)as a template.The properties of the material were examined by X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM),laser particle size analyzer,and coin cell tests.The material synthesized by two-step method(twostep LFP)had smaller particle size,which resulted in higher specific capacity and better rate performance than the one synthesized by one-step method(one-pot LFP).The discharge specific capacity of two-step LFP was about 136 mAh/g at 1 C,and for one-pot LFP 109 mAh/g at 1 C.After cycles,the capacity of two-step LFP had no significant attenuation,while the capacity of one-pot LFP quickly degraded to below 100 mAh/g after a few cycles.Study shown that the particle size had a critical effect on the electrochemical performance of LiFePO_(4),and the template was an effective way to control the particle size of LiFePO_(4)nanoparticle.