表面包覆Yb(OH)_3的球形氢氧化镍的高温性能研究

High-temperature Performances of Spherical Nickel Hydroxide Coated with Yb(OH)_3

球形氢氧化镍的高温性能已经成为制约其应用于动力型MH—Ni电池的主要因素．本文通过控制结晶的方法,在球形氢氧化镍表面包覆了一层Yb(OH)3,并研究了不同包覆量对其常温和高温性能的影响．研究结果表明:表面包覆了Yb(OH)3的球形氢氧化镍,其常温性能有所降低,但是高温性能得到了很大的提高．在60℃进行1C充放电条件下,包覆量为2％(摩尔比)的球形氢氧化镍其高温性能最好,其高温容量保持率可以达到92％．

The poor high-temperature performance of the spherical nickel hydroxide becomes the main reason for limitation of use as the positive electrode active material in MH-Ni battery, especially for the vehicle power. In the present work, different amount of ytterbium hydroxide layers were coated on the surface of the spherical nickel hydroxide by means of the controlled crystallization. The charge and discharge capacities were studied at room and high temperatures. The discharge capacity of the ytterbium-coated nickel hydroxide at room temperature was lower than that of the pure nickel hydroxide; however, its high-temperature performance was much higher than that of the pure spherical nickel hydroxide. The sample coated with 2% ytterbium hydroxide shows the best performance at 60℃ （1C）, its capacity retention can be retained about 92%.