废锂离子电池中失效钴酸锂材料超声再生

Regeneration of lithium cobalt oxide in spent lithium ion batteries by ultrasonic irradiation

为了恢复锂离子电池中正极钴酸锂材料的电化学活性,对置于LiOH溶液中的失效钴酸锂进行超声再生研究。采用XRD和Raman光谱分析钴酸锂晶体结构,采用SEM分析钴酸锂表面形貌和颗粒大小,采用FT-IR光谱仪和TGA热分析仪分析钴酸锂表面粘附的有机物。结果表明:超声空化效应可以有效地去除钴酸锂表面的有机物,并有利于钴酸锂晶体在LiOH溶液中Co和Li阳离子的重排。室温条件下,失效的钴酸锂在2.0 mol/L LiOH溶液中经过12 h超声处理后,成功恢复了其电化学活性。锂离子电池的首次充电容量为132.2 mA·h/g,首次放电容量为131.9 mA·h/g,第50次循环时的电容保持率为97.2%。

The spent LiCoO 2 was treated in LiOH solution exerted by ultrasound with the aim to renovate its electrochemical characteristics. The crystal structures of LiCoO2 were characterized by XRD and Raman spectroscopy, respectively. The morphology and particle sizes of LiCoO2 were analyzed by SEM. The organic substance adhered to the used LiCoO2 particle surfaces was determined by using Fourier transform infrared spectrometer （FT-IR） and thermogravimetric analysis （TGA）, respectively. The results show that ultrasonic cavitation can be effectively used to remove organic substance stuck on LiCoO2 surface and facilitate the cation rearrangement of Co＋ and Li＋ in LiOH. At room temperature, the spent LiCoO2 is successfully renovated in 2.0 mol/L LiOH solution treated by ultrasound for 12 h. The charge capacity in the first cycle is 132.2 mA-h/g, the discharge capacity is 131.9 mA-h/g, and 97.2% of the discharge capacity is retained after 50 cycles.