Positive Effect of Minor Manganese Doping on the Electrochemical Performance of LiFePO4/C under Extreme Conditions. (10th September 2015)

• Record Type: Journal Article
• Authors: Mi, Yingying; Yang, Chengkai; Zuo, Zicheng; Qi, Liya; Tang, Chunxia; Zhang, Weidong; Zhou, Henghui
• Is Part Of: Electrochimica acta. Volume 176(2015)
• Page Start: 642
• Page End: 648
• Publication Date: 2015-09-10
• Subjects: Lithium iron phosphate -- Mn doping -- Extreme conditions -- Low-temperature performance -- Rate performance; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.07.060
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Performance of LiFePO4 /C under extreme conditions is improved by trace Mn doping. Large-radius Mn doping enhances the Li + diffusion coefficient in LiFePO4 /C. Poor intrinsic kinetics of Mn retards the charge transfer process of LiFePO4 /C. Abstract: Uniform minor Mn-doped LiFePO4 /C cathode materials are synthesized and their electrochemical performances are investigated systematically. Via tuning the doping amount of Mn, it is found that the well crystallized LiFePO4 /C doped with 11000 ppm Mn gives the highest discharge capacity of 165 mAh g −1 at 0.1 C at room temperature. Remarkably, it holds a quite stable cycling performance at 45 °C, with capacity retention of 97.4% after 200 cycles using a high rate of 3.0 C, and its low-temperature (−20 °C) specific capacity maintains at high up to 131.4 mAh g −1 at 0.1 C, higher than that of the majority reports. The higher or lower Mn-doping amount than 11000 ppm is found to have less positive impact on the performance of LiFePO4 /C. Such phenomenon may be attributed to the negative cooperative effect of Mn doping, which enlarges the crystal space for improving the Li + transfer under low dose due to the large radius of Mn, but increases the charge transfer resistance and declines the performance under high dose owing to its poor intrinsic kinetics.