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Title: Visualization of electrochemically driven solid-state phase transformations using operando hard X-ray spectro-imaging

In situ techniques with high temporal, spatial and chemical resolution are key to understand ubiquitous solid-state phase transformations, which are crucial to many technological applications. Hard X-ray spectro-imaging can visualize electrochemically driven phase transformations but demands considerably large samples with strong absorption signal so far. Here we show a conceptually new data analysis method to enable operando visualization of mechanistically relevant weakly absorbing samples at the nanoscale and study electrochemical reaction dynamics of iron fluoride, a promising high-capacity conversion cathode material. In two specially designed samples with distinctive microstructure and porosity, we observe homogeneous phase transformations during both discharge and charge, faster and more complete Li-storage occurring in porous polycrystalline iron fluoride, and further, incomplete charge reaction following a pathway different from conventional belief. In conclusion, these mechanistic insights provide guidelines for designing better conversion cathode materials to realize the promise of high-capacity lithium-ion batteries.
 [1] ;  [2] ;  [2] ;  [3] ;  [1] ;  [4] ;  [3] ;  [5] ;  [2] ;  [1]
  1. Univ. of Wisconsin-Madison, Madison, WI (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Directorate
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Dept. of Sustainable Energy Technologies
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Univ. of Illinois, Chicago, IL (United States)
  5. Univ. of Illinois, Chicago, IL (United States)
Publication Date:
Grant/Contract Number:
SC0001294; SC0012583; AC02- 98CH10886
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
Energy Frontier Research Centers (EFRC); Northeastern Center for Chemical Energy Storage (NECCES)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
25 ENERGY STORAGE; energy storage (including batteries and capacitors); defects; charge transport; materials and chemistry by design; synthesis (novel materials)
OSTI Identifier: