Particle morphology, crystal orientation, and electrochemical reactivity of LiFePO4 synthesized by the hydrothermal method at 443 K
Particle morphology, crystal orientation, and electrochemical reactivity of LiFePO4 synthesized by the hydrothermal method at 443 K
复制标题
DOI：
10.1039/b711521k
复制
发表时间：
2007-01-01
影响因子：
--
通讯作者：
Kanamura, Kiyoshi
中科院分区：
文献类型：
--
作者：
Dokko, Kaoru;Koizumi, Shohei;Kanamura, Kiyoshi
采用水热法在443 K合成了LiFePO 4（空间群：Pnma）。前体溶液的pH在2.5和9.5之间系统地改变。所制备的LiFePO 4颗粒的颗粒形态、晶体取向和电化学反应性根据Li源的浓度和前体的pH而改变。从酸性溶液（pH约3.5）中获得的颗粒为针状颗粒。另一方面，从4 < pH < 6.5的弱酸性溶液中获得板状晶体。在高于7.2的pH下，颗粒变得随机形状。片状晶体在ac面有一个大的小平面，而针状颗粒在bc面有一个大的小平面。室温下，在碳酸乙烯酯和碳酸二乙酯体积比为1：1的混合溶剂中，加入1.0 mol dm（-3）LiClO 4，对所制备的LiFePO 4进行了电化学性能表征。在所制备的样品中，片状晶体表现出最高的电化学反应性，在17 mA g（-1）的电流密度下测量的放电容量为163 mA h g（-1）。
LiFePO4 (space group: Pnma) was synthesized by the hydrothermal method at 443 K. The pH of the precursor solution was systematically changed between 2.5 and 9.5. The particle morphology, crystal orientation, and electrochemical reactivity of the prepared LiFePO4 particles changed depending on the concentration of the Li source and pH of the precursor. The particles obtained from acidic solutions (pH approximate to 3.5) were needle-like particles. On the other hand, plate-like crystals were obtained from weak acidic solutions of 4 < pH < 6.5. At higher pH than 7.2, the particles became randomly shaped. The plate-like crystal had a large facet in the ac-plane, while the needle-like particles had a large facet in the bc-plane. The electrochemical properties of the prepared LiFePO4 were characterized in a mixed solvent of ethylene carbonate and diethyl carbonate with volume ratio of 1:1 containing 1.0 mol dm(-3) LiClO4 at room temperature. The plate-like crystals exhibited the highest electrochemical reactivity among the prepared samples, and the discharge capacity was 163 mA h g(-1) measured at a current density of 17 mA g(-1).