不同金属离子价态的前驱体制备球形LiNi1/3Mn1／3Co1／3O2的性能比较

Performance Comparison of Spherical LiNi_(1/3)Mn_(1/3)Co_(1/3)O_2 Prepared from the Precursor with Metal Ions of Different Valences

利用共沉淀法和控制结晶氧化法在不同条件下分别制备出低价态球形Ni1/3Co1/3Mn1/3(OH)2和高价态球形Ni1/3Co1/3Mn1/3OOH前驱体,并分别和LiOH·H2O在不同温度烧结合成出球形锂离子正极材料Li(Ni1/3Co1/3Mn1/3)O2。XPS分析表明,制备的高价态球形Ni1/3Co1/3Mn1/3OOH前驱体其过渡金属Ni、Co和Mn的价态分别是2+,3+,4+。XRD分析表明,高价态球形Ni1/3Co1/3Mn1/3OOH前驱体比低价态球形Ni1/3Co1/3Mn1/3(OH)2前驱体具有较高的活性,能够在低温下合成出Li(Ni1/3Co1/3Mn1/3)O2,而且制备的产物结晶度高,阳离子混排程度小,具有规整的层状α-NaFeO2结构。充放电实验表明,由高价态球形Ni1/3Co1/3Mn1/3OOH前驱体制备的Li(Ni1/3Co1/3Mn1/3)O2具有优良的充放电性能和循环性能。

High valency spherical Ni1/3Co1/3Mn1/3OOH and low valency spherical Ni1/3CO1/3Mn1/3（OH）2 precursor powders were synthesized respectively by co-precipitation method and oxidation method at different conditions. And then spherical Li（Ni1/3Co1/3Mn1/3）O2 powders were prepared at different temperature by their precursors, which were sintered with LiOH-H20. XPS studies indicated that the predominant oxidation states of Ni, Co and Mn in spherical precursor Ni1/3Co1/3Mn1/3OOH were 2^＋, 3^＋ and 4^＋, furthermore, the spherical Li（Ni1/3Co1/3Mn1/3）O2 powders with a well-ordered layered a-NaFeO2 structure and small amount of cation mixing can be synthesized at low temperature by Ni1/3Co1/3Mn1/3OOH, which indicated that the activity of spherical Ni1/3Co1/3Mn1/3OOH is higher than that of spherical Ni1/3Co1/3Mn1/3（OH）2. Charge and discharge capacity showed that the synthesized spherical cathodes by Ni1/3CO1/3Mn1/3OOH delivered higher discharge capacity and better cycling properties.