TY  - JOUR
JF  - ACS Applied Energy Materials
ID  - discovery10121546
UR  - https://doi.org/10.1021/acsaem.0c02010
N1  - This is an open access article published under a Creative Commons Non-Commercial No
Derivative Works (CC-BY-NC-ND) Attribution License, which permits copying and
redistribution of the article, and creation of adaptations, all for non-commercial purposes.
AV  - public
SN  - 2574-0962
N2  - Lithium uptake and release in lithium titanate (LTO) anode materials during a discharge and charge cycle is one of the fundamental processes of a lithium-ion battery (LIB), still not fully understood at the microscopic level. During the discharge cycle, LTO undergoes a phase transformation between Li4Ti5O12 and Li7Ti5O12 states within a cubic crystal lattice. To reveal the details of the microscopic mechanism, it is necessary to track the sequence of phase transformations at different discharge/charge states under operating conditions. Here, we use in situ Bragg coherent diffraction imaging (BCDI) and in situ X-ray diffraction (XRD) experiments to examine the lithium insertion-induced materials phase transformation within a single LTO particle and a bulk battery analogue, respectively. BCDI analysis from (111) Bragg peak shows the two-phase transformation manifesting as a distinct image phase modulation within a single LTO nanoparticle occurring in the middle of the discharge region then subsiding toward the end of the discharge cycle. We observe the biggest phase variation at the two-phase stage, indicating the formation of phase domains of 200 nm in size during the discharge process. We also observe a lattice contraction of >0.2% in a single LTO nanoparticle at the (400) Bragg peak measurement, larger than that in the corresponding bulk material. Our observation of this phase transformation at a single-particle level has implications for the understanding of the microscopic/mesoscale picture of the phase transformation in anode and cathode LIBs materials.
SP  - 111
VL  - 4
Y1  - 2021/01/04/
TI  - Imaging the Phase Transformation in Single Particles of the Lithium Titanate Anode for Lithium-Ion Batteries
IS  - 1
A1  - Assefa, TA
A1  - Suzana, AF
A1  - Wu, L
A1  - Koch, RJ
A1  - Li, L
A1  - Cha, W
A1  - Harder, RJ
A1  - Bozin, ES
A1  - Wang, F
A1  - Robinson, IK
KW  - coherent diffraction imaging
KW  -  image phase variation
KW  -  displacement field
KW  -  battery material
KW  -  lithium titanate anode
EP  - 118
ER  -