不同形态的锰酸锂晶体的熔融盐法制备及对其对充放电性的影响(英文)

MORPHOLOGY CONTROL OF LITHIUM MANGANESE OXIDES BY FLUX METHOD AND ITS EFFECTS ON CHARGE/DISCHARGE PROPERTIES

论述了不同形状和大小的锰酸锂晶体的熔融盐制备法,以及尖晶石型锰酸锂晶体的形 状和大小对充放电特性的影响。氧化锰微孔晶体以[MnO6]八面体为基本单元,用共棱和/或 共角的连接方式组成一维隧道、二维层状和三微网络的多样化的微孔结构,这些结构中的遂 道、层和空位是传送离子的通道。影响离子传送的因素除了结晶结构以外,还同晶体的形态和 大小有关。熔融化盐法是控制锰酸锂晶体的形态和大小的有效的方法,通过选择熔融盐的种 类和控制制备条件可得到不同组成、不同形态和大小的晶体。把不同组成、不同形状和大小的 尖晶石型锰酸锂晶体作为锂电池的正极材料,探讨了电池的充放电性能,发现薄片或针状的富 锂组成的锰酸锂晶体可有效的提高其充放电容量和改善充放电特循环特性。

The article reviews the effects of morphology and size of lithium manganese oxide crystals on their electrochemical properties. The dimension and direction of the lithium ion path vary with the crystal structure of lithium manganese oxides. Therefore, the distance of lithium migration during electrochemical reaction depends on the structure as well as morphology and size of lithium manganese oxide crystals in the cathode material. Crystallization in a Li-containing flux is an effective method of controlling the morphology and size of lithium manganese oxide. A variety of lithium manganese oxides with different chemical compositions and morphology can be obtained by controlling the preparation conditions. The electrochemical studies for spinel-type lithium manganese oxides suggest that crystals having a lithium-rich composition and thin plate or needle shape are better suited as a cathode material in terms of improving capacity and recyclability.