人工晶体学报, 2020, 49 (10): 1870, 网络出版: 2021-01-09
冷冻干燥辅助溶胶凝胶法合成Li1.2Ni0.2Mn0.6O2正极材料及电化学性能改善研究
Improved Electrochemical Performance of Li1.2Ni0.2Mn0.6O2 Cathode Materials Synthesized by Freeze-Drying Assisted Sol-Gel Method
锂离子电池 富锂锰基 正极材料 冷冻干燥 溶胶凝胶 电化学性能 lithium ion battery Li-rich Mn-based cathode material freeze-drying sol-gel electrochemical performance
摘要
采用冷冻干燥辅助溶胶凝胶法合成富锂锰基Li1.2Ni0.2Mn0.6O2正极材料,并将其结构、形貌以及电化学性能与传统溶胶凝胶法合成的材料进行比较。X射线衍射(XRD)结果表明,通过冷冻干燥辅助溶胶凝胶法合成的Li1.2Ni0.2Mn0.6O2粉末阳离子混排程度更低,冷冻干燥工艺的参与可以改善晶体结构。扫描电镜(SEM)照片分析表明,与溶胶凝胶样品相比较,冷冻干燥辅助溶胶凝胶法合成样品的颗粒团聚程度较低。电化学性能测试结果表明,冷冻干燥辅助溶胶凝胶法合成的材料具有更好的倍率性能和循环性能。除此之外,电化学交流阻抗测试(EIS)结果表明,冷冻干燥辅助溶胶凝胶法合成的Li1.2Ni0.2Mn0.6O2电荷转移电阻低于溶胶凝胶法制备的材料,增强了反应动力学。
Abstract
Li-rich Mn-based Li1.2Ni0.2Mn0.6O2 cathode materials were synthesized by freeze-drying assisted sol-gel method, and its structure, morphology, and electrochemical performance were compared with the same materials synthesized by traditional sol-gel method. XRD results show that the Li1.2Ni0.2Mn0.6O2 powders synthesized by freeze-drying assisted sol-gel method exhibit lower cation mixing, and the crystalline structure is improved by the presence of freeze-drying process. SEM images indicate that the extent of particle agglomeration of the materials synthesized by freeze-drying assisted sol-gel method is lower compared to the sol-gel sample. Electrochemical test results indicate that the materials synthesized by freeze-drying assisted sol-gel method exhibited better rate capability and cyclability. Besides, EIS results suggest that the charge transfer resistance of Li1.2Ni0.2Mn0.6O2 synthesized by freeze-drying assisted sol-gel method is much lower than that of the Li1.2Ni0.2Mn0.6O2 prepared by sol-gel method, which enhances the reaction kinetics.
段文杰, 江友良, 刘赛求, 廖启军, 向延鸿, 吴贤文, 熊利芝, 何则强. 冷冻干燥辅助溶胶凝胶法合成Li1.2Ni0.2Mn0.6O2正极材料及电化学性能改善研究[J]. 人工晶体学报, 2020, 49(10): 1870. DUAN Wenjie, JIANG Youliang, LIU Saiqiu, LIAO Qijun, XIANG Yanhong, WU Xianwen, XIONG Lizhi, HE Zeqiang. Improved Electrochemical Performance of Li1.2Ni0.2Mn0.6O2 Cathode Materials Synthesized by Freeze-Drying Assisted Sol-Gel Method[J]. Journal of Synthetic Crystals, 2020, 49(10): 1870.