In situ Raman spectroscopy of LiFePO4: Size and morphology dependence during charge and self-discharge

Jing Wu, Gopi Krishna Phani Dathar, Chunwen Sun, Murali G. Theivanayagam, Danielle Applestone, Anthony G. Dylla, Arumugam Manthiram, Graeme Henkelman, John B. Goodenough, Keith J. Stevenson

Результат исследований: Вклад в журналСтатьярецензирование

61 Цитирования (Scopus)


Previous studies of the size dependent properties of LiFePO4 have focused on the diffusion rate or phase transformation pathways by bulk analysis techniques such as x-ray diffraction (XRD), neutron diffraction and electrochemistry. In this work, in situ Raman spectroscopy was used to study the surface phase change during charge and self-discharge on a more localized scale for three morphologies of LiFePO4: (1) 25 ± 6 nm width nanorods, (2) 225 ± 6 nm width nanorods and (3) ∼2 μm porous microspheres. Both the large nanorod and microsphere geometries showed incomplete delithiation at the end of charge, which was most likely caused by anti-site defects along the 1D diffusion channels in the bulk of the larger particles. Based on the in situ Raman measurements, all of the morphologies studied exhibited self-discharge with time. Among them, the smallest FePO 4 particles self-discharged (lithiated) the fastest. While nanostructuring LiFePO4 can offer advantages in terms of lowering anti-site defects within particles, it also creates new problems due to high surface energies that allow self-discharge. The in situ Raman spectroscopy also showed that carbon coating did not provide significant improvement to the stability of the lithiated particles.

Язык оригиналаАнглийский
Номер статьи424009
Номер выпуска42
СостояниеОпубликовано - 25 окт. 2013
Опубликовано для внешнего пользованияДа


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