Preparation of co-doped spherical spinel LiMn2O4 cathode materials for Li-ion batteries

• Published in: Journal of power sources Vol. 150; pp. 216 - 222
• Main Authors: He, Xiangming, Li, Jianjun, Cai, Yan, Wang, Yaowu, Ying, Jierong, Jiang, Changyin, Wan, Chunrong
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier Sequoia 04.10.2005
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Scanning electron microscopy; Elevated temperature; Cathode; Doped materials; Secondary cell; Electrode material; Cobalt; Discharge charge cycle; Spherical spinel LiMn2O4:Co-doping; Lithium battery; Lithium Manganates Oxides; Spinel; Performance; Yttrium
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2005.02.029

Surface cobalt doping and bulk yttrium doping were combined to improve the cycling stability of spherical spinel LiMn2O4 at elevated temperature (55 DGC). The cobalt surface doping was more effective than cobalt bulk doping at the same doping level, because the surface cobalt doping prevents more efficiently manganese from dissolving in electrolyte. At yttrium doping level of 5%, doped spinel LiMn204 had specific capacity in excess of 130 mAh g-1 and 120 mAh g-1 at first cycle and at 100th cycle, respectively, at 25 DGC. Doping of yttrium enhanced the activity of manganese in spinel LiMn2O4, leading to both increase of specific capacity and decrease of cycleability, because the active manganese easily dissolved into electrolyte during cycling. Moreover, the raise of the temperature led to an intensive dissolution of manganese and poor performance at elevated temperature when yttrium doped. The dissolution could be effectively inhibited by cobalt surface doping. 0.5% yttrium bulk and 0.5% cobalt surface co-doped spherical spinel LiMn204 had the excellent performance, and its initial specific capacities are 118 mAh g -1 and 110 mAh g-1 at 25 DGC and 55 DGC, respectively, and its 50th cycle specific capacities remained to be 114 mAh g-1 and 91 mAh g -1 at 25 DGC and 55 DGC, respectively.