Yang Jinxing, Li Changji, Guang Tianjia, Zhang Hui, Li Zhaojin, Fan Bingbing, Ma Yonghui, Zhu Kongjun, Wang Xiaohui
School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China.
Energy Geoscience Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Nano Lett. 2021 Jun 23;21(12):5091-5097. doi: 10.1021/acs.nanolett.1c00957. Epub 2021 Jun 1.
Forming olivine-structured Li(Mn,Fe)PO solid solution is theoretically a feasible way to improve the energy density of the solid solutions for lithium ion batteries. However, the Jahn-Teller active Mn in the solid solution restricts their energy density and rate performance. Here, as demonstrated by operando X-ray diffraction, we show that equimolar LiMnFePO solid solution nanocrystals undergo a single-phase transition during the whole (de)lithiation process, with a feature of zero lithium miscibility gap, which endows the nanocrystals with excellent electrochemical properties. Specifically, the energy density of LiMnFePO reaches 625 Wh kg, which is 16% higher than that of LiFePO. Moreover, the high-performance LiMnFePO nanocrystals are prepared by a microwave-assisted hydrothermal synthesis in pure water.
形成橄榄石结构的Li(Mn,Fe)PO固溶体理论上是提高锂离子电池固溶体能量密度的一种可行方法。然而，固溶体中具有 Jahn-Teller 活性的 Mn 限制了它们的能量密度和倍率性能。在此，通过原位X射线衍射表明，我们发现等摩尔的LiMnFePO固溶体纳米晶体在整个（脱）锂过程中经历单相转变，具有零锂混溶间隙的特征，这赋予了纳米晶体优异的电化学性能。具体而言，LiMnFePO的能量密度达到625 Wh kg，比LiFePO高16%。此外，高性能的LiMnFePO纳米晶体是通过在纯水中微波辅助水热合成制备的。
