摘要
通过两步固相法反应制备LiFePO4/C和LiFePO3.92F0.08/C。采用XRD、红外(FTIR)、扫描电镜(SEM)、X射线能谱(EDS)对样品的结构和形貌进行分析。结果表明LiFePO3.92F0.08/C中有F的分布并且仍然保持橄榄石结构,但是具有了更好的倍率性能和循环稳定性能。LiFePO3.92F0.08/C在不同倍率下的首次放电比容量分别为154.9(0.2 C)、124.3(1 C)、83.2 mAh/g(10 C)。特别是在1 C倍率下循环30次后,放电比容量仍达122.1 mAh/g,容量损失仅为2.16%。F-掺杂能够提高材料电子电导率和锂离子扩散系数进而显著改善其电化学性能。
LiFePO4/C and LiFePO3.92F0.08/C were prepared by two-step solid-state reaction.The structure and morphology of the samples were analyzed by X-ray diffractometry（ XRD）,Fourier transform infrared（ FTIR） spectrometer,scanning electron microscope（ SEM） and Energy Dispersive X-Ray Spectroscopy（ EDS）.The results show that LiFePO3.92F0.08/C has F distribution and still maintains the olivine structure of LiFePO4/C,but has better rate performance and cyclic stability than those of LiFePO4/C.The first corresponding specific discharge capacities of LiFePO3.92F0.08/C is 154.9 mAh /g at0.2 C rate,124.3 mAh /g at 1 C rate,and 83.2 mAh /g at 10 C rate,respectively.Specially,the specific discharge capacity of LiFePO3.92F0.08/C was 122.1 mAh /g at 1 C after 30 cycles,only 2.16%loss of the capacity.F-doping can help improve electrochemical performance by increasing electron conductivity and Li＋diffusion of LiFePO4/C.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2014年第9期2307-2312,2318,共7页
Journal of Synthetic Crystals
基金
National Natural Science Foundation of China(51364008)
Science Technology Research Projects of Guangxi Institution of Higher Education(2013ZD030)
Guangxi Natural Science Foundation(2014GXNSFAA118046)
