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Length‐Scale‐Dependent Phase Transformation of LiFePO 4 : An In situ and Operando Study Using Micro‐Raman Spectroscopy and XRD
Author(s) -
Siddique N. A.,
Salehi Amir,
Wei Zi,
Liu Dong,
Sajjad Syed D.,
Liu Fuqiang
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201500299
Subject(s) - raman spectroscopy , phase (matter) , materials science , transformation (genetics) , analytical chemistry (journal) , diffraction , in situ , particle (ecology) , lithium (medication) , spectroscopy , atomic units , chemical engineering , chemistry , optics , physics , chromatography , medicine , biochemistry , oceanography , organic chemistry , engineering , quantum mechanics , endocrinology , gene , geology
The charge and discharge of lithium ion batteries are often accompanied by electrochemically driven phase‐transformation processes. In this work, two in situ and operando methods, that is, micro‐Raman spectroscopy and X‐ray diffraction (XRD), have been combined to study the phase‐transformation process in LiFePO 4 at two distinct length scales, namely, particle‐level scale (∼1 μm) and macroscopic scale (∼several cm). In situ Raman studies revealed a discrete mode of phase transformation at the particle level. Besides, the preferred electrochemical transport network, particularly the carbon content, was found to govern the sequence of phase transformation among particles. In contrast, at the macroscopic level, studies conducted at four different discharge rates showed a continuous but delayed phase transformation. These findings uncovered the intricate phase transformation in LiFePO 4 and potentially offer valuable insights into optimizing the length‐scale‐dependent properties of battery materials.