@article{discovery10121546,
           pages = {111--118},
         journal = {ACS Applied Energy Materials},
           month = {January},
            note = {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.},
          number = {1},
           title = {Imaging the Phase Transformation in Single Particles of the Lithium Titanate Anode for Lithium-Ion Batteries},
            year = {2021},
          volume = {4},
          author = {Assefa, TA and Suzana, AF and Wu, L and Koch, RJ and Li, L and Cha, W and Harder, RJ and Bozin, ES and Wang, F and Robinson, IK},
             url = {https://doi.org/10.1021/acsaem.0c02010},
        abstract = {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 {\ensuremath{>}}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.},
            issn = {2574-0962},
        keywords = {coherent diffraction imaging, image phase variation, displacement field, battery material, lithium titanate anode}
}