@article{32136,
  author = {Young-Sang Yu and Chunjoong Kim and David A Shapiro and Maryam Farmand and Danna Qian and Tolek Tyliszczak and A L. David Kilcoyne and Rich Celestre and Stefano Marchesini and John Joseph and Peter Denes and Tony Warwick and Fiona C Strobridge and Clare P Grey and Howard Padmore and Ying Shirley Meng and Robert Kostecki and Jordi Cabana},
  title = {Dependence on Crystal Size of the Nanoscale Chemical Phase Distribution and Fracture in Li<sub><i>x</i></sub>FePO<sub>4</sub>},
  abstract = {<p><span>The performance of battery electrode materials is strongly affected by inefficiencies in utilization kinetics and cycle life as well as size effects. Observations of phase transformations in these materials with high chemical and spatial resolution can elucidate the relationship between chemical processes and mechanical degradation. Soft X-ray ptychographic microscopy combined with X-ray absorption spectroscopy and electron microscopy creates a powerful suite of tools that we use to assess the chemical and morphological changes in lithium iron phosphate (LiFePO</span><sub><span>4</span></sub><span>) micro- and nanocrystals that occur upon delithiation. All sizes of partly delithiated crystals were found to contain two phases with a complex correlation between crystallographic orientation and phase distribution. However, the lattice mismatch between LiFePO</span><sub><span>4</span></sub><span>&nbsp;and FePO</span><sub><span>4</span></sub><span>&nbsp;led to severe fracturing on microcrystals, whereas no mechanical damage was observed in nanoplates, indicating that mechanics are a principal driver in the outstanding electrode performance of LiFePO</span><sub><span>4</span></sub><span>&nbsp;nanoparticles. These results demonstrate the importance of engineering the active electrode material in next generation electrical energy storage systems, which will achieve theoretical limits of energy density and extended stability. This work establishes soft X-ray ptychographic chemical imaging as an essential tool to build comprehensive relationships between mechanics and chemistry that guide this engineering design.</span></p>},
  year = {2015},
  journal = {Nano Letters},
  volume = {15},
  pages = {4282 - 4288},
  month = {07/2015},
  issn = {1530-6984},
  doi = {10.1021/acs.nanolett.5b01314},
  language = {eng},
}