MoO_3氧化物掺杂改善LiFePO_4/乙炔黑电化学性能研究  

Research of LiFePO_4/Acetylene Electrochemical Performance by Doping MoO_3

作　　者：章明[1] 焦丽芳[1] 袁华堂[1] 赵明[1] 王永梅[1] 

机构地区：[1]南开大学新能源材料化学研究所,天津300071

出　　处：《无机化学学报》2006年第5期839-844,共6页Chinese Journal of Inorganic Chemistry

基　　金：国家973项目基础研究基金(No.2002CB211800);天津市自然科学基金资助项目

摘　　要：采用MoO3氧化物前驱物对磷酸铁锂(LiFePO4)进行少量的掺杂,并用XRD、SEM、CV及恒流充放电测试对产物进行了研究。研究表明,少量的掺杂并未影响到LiFePO4的晶体结构,但却能够在一定程度上改善LiFePO4的电化学性能。其中650℃焙烧的1%Mo掺杂的LiFePO4材料性能较好,该材料在以0.2C的倍率充放电时,充放电曲线具有平稳的电压平台和较大的充放电容量,首次放电容量能达到143mAh·g-1,循环50周后仍具有129mAh·g-1的容量。在此种材料中添加10%乙炔黑(质量分数)后首次放电容量能达到158mAh·g-1,充放电循环50周后,容量为145mAh·g-1,衰减较少。后者在以0.5C和1.0C的充放电倍率下,分别具有145mAh·g-1及130mAh·g-1的初始放电容量。Lithium iron phosphate （LiFePO4） containing low concentration ion dopants was prepared by mixing precursors with metal oxides （MoO3）. The samples were characterized by X-ray diffraction, cyclic voltammetry and scanning electron microscope, and their electrochemical performances were investigated including cycling behavior and current discharging. The results indicate that the Mo^6＋ dopant does not affect the structure of the material, but improves its kinetics in terms of capacity delivery and cycle performance in certain extent. The capability of LiFePO4 doped with 1.0% Mo calcined at 650 ℃ are better than that of samples calcined at 550 ℃ and 750 ℃. When batteries are cycled at a rate of 0.2C, the charge and discharge curves show flat work voltages and large capacities, the first discharge capacity is 143 mAh·g^-1, after 50 cycles, the capacity of sample still possesses 129 mAh·g^-1 which shows preferable electrochemical performance. In addition, the sample doped with acetylene shows better capacity of 158mAh·g^-1 in first discharge and stable cycleability by possessing 145 mAh·g^-1 after 50 cycles, the capacity fade is neglectable. When the charge-discharge rate is increased to 0.5 C and 1.0 C, the sample doped with acetylene shows capacity of 145 mAh·g^-1 and 130 mAh·g^-1, respectively.

关 键 词：磷酸铁锂 金属氧化物 掺杂 电化学性能 

分 类 号：O611.4[理学—无机化学] O614.111[理学—化学]