Journal of Power Sources ( IF 8.1 ) Pub Date : 2017-11-13 , DOI: 10.1016/j.jpowsour.2017.11.018 Jongsoon Kim , Hyungsub Kim , Seung-Taek Myung , Jung-Keun Yoo , Seongsu Lee
Mn-rich olivine LiFe0.3Mn0.7PO4 is homogenously encapsulated by an ∼3-nm-thick conductive nanolayer composed of the glassy lithium fluorophosphate through simple non-stoichiometric synthesis using additives of small amounts of LiF and a phosphorus source. The coating of the glassy lithium fluorophosphate nanolayer is clearly verified using transmission electron microscopy and X-ray photoelectron spectroscopy. It enables significant decrease in charge transfer resistance of LiFe0.3Mn0.7PO4 and improvement of its sluggish Li diffusion. At a rate of 10C, the LiFe0.3Mn0.7PO4 encapsulated by conductive glassy lithium fluorophosphate (LiFe0.3Mn0.7PO4-GLFP) electrode delivers a capacity of ∼130 mAh g−1, which is ∼77% of its theoretical capacity (∼170 mAh g−1) and ∼1.5 times higher than that of the pristine counterpart at 10C. Furthermore, LiFe0.3Mn0.7PO4-GLFP achieves outstanding cycle stability (∼75% retention of its initial capacity over 500 cycles at 1C). The proposed olivine LiFe0.3Mn0.7PO4-GLFP battery is thus expected to be a promising candidate for large-scale energy storage applications.
中文翻译:
玻璃状氟磷酸锂对高性能锂离子电池中富锰橄榄石正极材料的特殊影响
富锰橄榄石LiFe 0.3 Mn 0.7 PO 4通过使用少量LiF和磷源的简单非化学计量合成,由玻璃状氟磷酸锂组成的厚度约为3nm的导电纳米层均匀包裹。使用透射电子显微镜和X射线光电子能谱清楚地验证了玻璃状氟磷酸锂纳米层的涂层。它可以显着降低LiFe 0.3 Mn 0.7 PO 4的电荷转移电阻,并改善其缓慢的Li扩散。在10C的速率下,LiFe 0.3 Mn 0.7 PO 4用导电玻璃态氟代磷酸锂(LiFe 0.3 Mn 0.7 PO 4 -GLFP)电极封装的容量约为130 mAh g -1,是其理论容量(约170 mAh g -1)的约77%,约为其1.5倍比原始温度在10摄氏度时要高。此外,LiFe 0.3 Mn 0.7 PO 4 -GLFP实现了出色的循环稳定性(在1C的500个循环中,其初始容量保留了约75%)。因此,所提出的橄榄石型LiFe 0.3 Mn 0.7 PO 4 -GLFP电池有望成为大规模储能应用的有前途的候选者。