title: BATTERIES. Topological defect dynamics in operando battery nanoparticles.
abstract: Topological defects can markedly alter nanomaterial properties. This presents opportunities for "defect engineering," where desired functionalities are generated through defect manipulation. However, imaging defects in working devices with nanoscale resolution remains elusive. We report three-dimensional imaging of dislocation dynamics in individual battery cathode nanoparticles under operando conditions using Bragg coherent diffractive imaging. Dislocations are static at room temperature and mobile during charge transport. During the structural phase transformation, the lithium-rich phase nucleates near the dislocation and spreads inhomogeneously. The dislocation field is a local probe of elastic properties, and we find that a region of the material exhibits a negative Poisson's ratio at high voltage. Operando dislocation imaging thus opens a powerful avenue for facilitating improvement and rational design of nanostructured materials.
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, CA 92093-0319, USA.
authors.forename: A
authors.initials: A
authors.lastname: Ulvestad
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, CA 92093-0319, USA.
authors.forename: A
authors.initials: A
authors.lastname: Singer
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory Menlo Park, CA 94025, USA. Center for Free-Electron Laser Science (CFEL), Deutsches Elektronensynchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany.
authors.forename: J N
authors.initials: JN
authors.lastname: Clark
authors.affiliation: Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92093-0448, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Cho
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, CA 92093-0319, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: R
authors.initials: R
authors.lastname: Harder
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: J
authors.initials: J
authors.lastname: Maser
authors.affiliation: Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92093-0448, USA. shmeng@ucsd.edu oshpyrko@physics.ucsd.edu.
authors.forename: Y S
authors.initials: YS
authors.lastname: Meng
authors.affiliation: Department of Physics, University of California-San Diego, La Jolla, CA 92093-0319, USA. shmeng@ucsd.edu oshpyrko@physics.ucsd.edu.
authors.forename: O G
authors.initials: OG
authors.lastname: Shpyrko