Abstract
This work explores the complex interplay between slurry aggregation, agglomeration, and conformation (i.e., shape) of poly(acrylic acid) (PAA)- and lithiated PAA-based silicon slurries as a function of the shear rate and the resulting slurry homogeneity. These values were measured by small-angle neutron scattering (SANS) and rheology-coupled ultra-SANS at conditions relevant to battery electrode casting. Different binder solution preparation methods, either a ball milling (BM) process or a planetary centrifugal mixing (PCM) process, dramatically modify the resulting polymer dynamics and organization around a silicon material. This is due to the different energy profiles of mixing where the more violent and higher energy PCM causes extensive breakdown and reformation of the binder, which is now likely in a branched conformation, while the lower energy BM results in simply lower-molecular weight linear polymers. The breakdown and reorganization of the polymer structure affect silicon slurry homogeneity, which affects subsequent electrode architecture.
| Original language | English |
|---|---|
| Pages (from-to) | 2447-2460 |
| Number of pages | 14 |
| Journal | ACS Applied Polymer Materials |
| Volume | 3 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 14 2021 |
Funding
This research (MKBT, BLA, AR, GMV) was supported by the U.S. Department of Energy’s Vehicle Technologies Office under the Silicon Consortium Project, directed by Brian Cunningham, and managed by Anthony Burrell. The authors thank Paul D. Butler and Markus Bleuel for facilitating the measurements at NIST and for their helpful discussions. The authors would also like to acknowledge Ryan Armstrong for his insightful observations that sent us down this research path. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory (MD and LH). A portion of the ultra-small-angle scattering measurements were done using the USANS instrument at the Spallation Neutron Source. Access to the NG7-SANS and BT-5 USANS instruments was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. This work benefited from the use of the SasView application, originally developed under NSF award DMR-0520547. SasView contains code developed with funding from the European Union’s Horizon 2020 research and innovation program under the SINE2020 project, grant agreement no. 654000. The authors would like to thank Steven Trask and Bryant Polzin at the ANL CAMP Facility for supplying the silicon materials. This manuscript has been authored by UT-Battelle, LLC, under Contract DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow other to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). Commercial equipment and materials identified in this work do not imply recommendation nor endorsement by the National Institute of Standards and Technology.
Keywords
- binder/polymer processing
- electrode architecture
- lithiated poly(acrylic acid)
- poly(acrylic acid)
- rheology-coupled ultra-small-angle neutron scattering (USANS)
- slurry dynamics
- small-angle neutron scattering (SANS)