Besides Li＋ and Mg2＋, the electrochemical behavior of Na^＋ and K＋ in LiFePO4/FePO4 structures was studied since they naturally coexist with Li＋ and Mg2＋ in brine. The cyclic voltammogram （CV） results indicated...Besides Li＋ and Mg2＋, the electrochemical behavior of Na^＋ and K＋ in LiFePO4/FePO4 structures was studied since they naturally coexist with Li＋ and Mg2＋ in brine. The cyclic voltammogram （CV） results indicated that Na＋ exhibits some reversibility in LiFePO4/FePO4 structures. Its reduction peak appears at -0.511 V, more negative than that of Li＋ （-0.197 V）, meaning that a relatively positive potential is beneficial for decreasing Na＋ insertion. The reduction peak of K＋ could not be found clearly, indicating that K＋ is difficult to insert into the FePO4 structure. Furthermore, technical experiments using real brine with a super high Mg/Li ratio （493） at a cell voltage of 0.7V showed that the final extracted capacity of Li＋, Mg2＋ and Na＋ that can be attained in 1 g LiFePO4 is 24.1 mg, 7.32 mg and 4.61 mg, respectively. The Mg/Li ratio can be reduced to 0.30 from 493, and the Na/Li ratio to 0.19 from 16.7, which proves that, even in super high Mg/Li ratio brine, if a cell voltage is appropriately controlled, it is possible to separate Li^＋ and other impurities effectively.展开更多
以草酸盐、磷酸盐和碳酸盐为原料,采用喷雾干燥法制备前驱体,经固相烧结制得钠离子电池NaFePO_4正极材料。通过X射线衍射分析、扫描电镜、激光衍射粒度分析、充放电测试、循环伏安法对材料进行了结构、形貌及电化学性能表征。结果表明,...以草酸盐、磷酸盐和碳酸盐为原料,采用喷雾干燥法制备前驱体,经固相烧结制得钠离子电池NaFePO_4正极材料。通过X射线衍射分析、扫描电镜、激光衍射粒度分析、充放电测试、循环伏安法对材料进行了结构、形貌及电化学性能表征。结果表明,喷雾干燥制得了球形前驱体,经低温烧结的钠离子电池NaFePO_4正极材料具有良好的电化学活性,其嵌钠平台在3.0 V左右,在0.1C倍率下,其首次放电容量为100 m Ah/g,经过30次循环,其可逆放电比容量达93 m Ah/g。展开更多
通过溶胶凝胶法制备了磷铁钠矿型NaFePO_4/C钠离子电池正极材料,然后利用X射线衍射(XRD)、扫描电子显微镜(SEM)以及X射线能量色散光谱(EDX)研究了磷铁钠矿型NaFePO_4/C正极材料的微观结构及形貌;并进一步利用恒流充/放电及循环伏安(CV)...通过溶胶凝胶法制备了磷铁钠矿型NaFePO_4/C钠离子电池正极材料,然后利用X射线衍射(XRD)、扫描电子显微镜(SEM)以及X射线能量色散光谱(EDX)研究了磷铁钠矿型NaFePO_4/C正极材料的微观结构及形貌;并进一步利用恒流充/放电及循环伏安(CV)技术测试了其电化学性能。结果表明:所制备的磷铁钠矿型NaFePO_4/C正极在0.1 C时的首次放电比容量约为26.9 m Ah/g,经过50次循环后,电极的容量保持率为98.6%,而且在1.0 C时的可逆放电比容量仍为15.5 m Ah/g,表现了满意的充/放电循环稳定性和倍率性能,在对电池容量要求不高的应用场合中优势更加明显。展开更多
基金Project(K1205034-11) supported by Technology Program of Changsha,China
文摘Besides Li＋ and Mg2＋, the electrochemical behavior of Na^＋ and K＋ in LiFePO4/FePO4 structures was studied since they naturally coexist with Li＋ and Mg2＋ in brine. The cyclic voltammogram （CV） results indicated that Na＋ exhibits some reversibility in LiFePO4/FePO4 structures. Its reduction peak appears at -0.511 V, more negative than that of Li＋ （-0.197 V）, meaning that a relatively positive potential is beneficial for decreasing Na＋ insertion. The reduction peak of K＋ could not be found clearly, indicating that K＋ is difficult to insert into the FePO4 structure. Furthermore, technical experiments using real brine with a super high Mg/Li ratio （493） at a cell voltage of 0.7V showed that the final extracted capacity of Li＋, Mg2＋ and Na＋ that can be attained in 1 g LiFePO4 is 24.1 mg, 7.32 mg and 4.61 mg, respectively. The Mg/Li ratio can be reduced to 0.30 from 493, and the Na/Li ratio to 0.19 from 16.7, which proves that, even in super high Mg/Li ratio brine, if a cell voltage is appropriately controlled, it is possible to separate Li^＋ and other impurities effectively.
文摘以草酸盐、磷酸盐和碳酸盐为原料,采用喷雾干燥法制备前驱体,经固相烧结制得钠离子电池NaFePO_4正极材料。通过X射线衍射分析、扫描电镜、激光衍射粒度分析、充放电测试、循环伏安法对材料进行了结构、形貌及电化学性能表征。结果表明,喷雾干燥制得了球形前驱体,经低温烧结的钠离子电池NaFePO_4正极材料具有良好的电化学活性,其嵌钠平台在3.0 V左右,在0.1C倍率下,其首次放电容量为100 m Ah/g,经过30次循环,其可逆放电比容量达93 m Ah/g。
文摘通过溶胶凝胶法制备了磷铁钠矿型NaFePO_4/C钠离子电池正极材料,然后利用X射线衍射(XRD)、扫描电子显微镜(SEM)以及X射线能量色散光谱(EDX)研究了磷铁钠矿型NaFePO_4/C正极材料的微观结构及形貌;并进一步利用恒流充/放电及循环伏安(CV)技术测试了其电化学性能。结果表明:所制备的磷铁钠矿型NaFePO_4/C正极在0.1 C时的首次放电比容量约为26.9 m Ah/g,经过50次循环后,电极的容量保持率为98.6%,而且在1.0 C时的可逆放电比容量仍为15.5 m Ah/g,表现了满意的充/放电循环稳定性和倍率性能,在对电池容量要求不高的应用场合中优势更加明显。
