超声空化预处理对尖晶石LiMn_2O_4性能的影响

Effects of ultrasonic cavitation pretreatment on the performance of spinel LiMn_2O_4

采用超声空化-固相合成法制备尖晶石LiMn2O4,用TG-DTA、XRD、SEM、激光粒度分析和充放电测试等研究了超声空化对材料的组成、晶体结构、表观形貌、粒度分布和电化学性能的影响。结果表明:超声空化产生的机械活化效应降低了材料的合成温度,提高了尖晶石LiMn2O4的结晶度和结构稳定性;超声空化对材料制备过程中的加速成核和控制晶核的生长是有利的,能得到较好的颗粒形貌和粒度分布;经过超声空化预处理的样品的首次放电比容量为125.34 mAh/g,20次循环后的容量仅衰减5.54%。

Spinel LiMn2O4 was synthesized by ultrasonic cavitation-solid state reaction. The effects of ultrasonic cavitation on the component, crystal structure, apparent morphology, particle size distribution and electrochemical performance of the material were studied by TG-DTA, XRD, SEM, laser grading analysis and charge-discharge tests. The results showed that the synthesis temperature of the material reduced because of the mechanical activating effect aroused by ultrasonic cavitation, the crystallization and the structure stability of spinel LiMn2O4 were improved. The ultrasonic cavitation was favorable for accelerating nucleation and controlling crystal growth in the course of the material preparation and the material had better particle morphology and particle size distribution. The initial specific discharge capacity of the sample treated! by ultrasonic cavitation was 125.34 mAh/g and the capacity decreased only 5.54% after 20 cycles.