Fig. 1. Schematic illustrations depicting the particle size dependent phase evolutions of olivine FePO4 particles during lithiation or sodiation. From G. Yan et al., © 2024 Springer Nature Limited
With renewable energy sources at the forefront of the energy marketplace, the demand for lithium (Li) to use in ubiquitous lithium-ion (Li-ion) batteries continues to rise. Given that so much of the readily available Li supply is not found within the U.S., new techniques for obtaining Li from unexpected sources is increasingly the subject of intense research.
One-dimensional (1-D) olivine iron phosphate (FePO4) has been a popular candidate for use in electrochemical Li extraction from dilute water sources. But ion selectivity (the critical ability to select for specific ionic species, i.e. in this case Li) was governed by different physical characteristics of the particles. Gaining an understanding of the ways particle features influence Li and sodium (Na) co-intercalation (the reversible inclusion or insertion of a molecule or ion into layered materials with layered structures) is crucial for system design and for enhancing Li selectivity.
A team of researchers from the University of Chicago; the Illinois Institute of Technology; Argonne National Laboratory; and the University at Buffalo, The State University of New York studied a variety of FePO4 particles with different features. They discovered the criticality of using the kinetic and chemo-mechanical barrier difference between lithiation and sodiation to promote selectivity.
They employed X-ray diffraction to characterize the components of synthesized FePO4 powder. To carry out these studies, they utilized both an in-house diffractometer and several synchrotron X-ray beamlines at the U.S. Department of Energy’s Advanced Photon Source (APS) including anomalous small- and wide-angle x-ray Scattering (ASWAXS) facility of NSF’s ChemMatCARS.
For the synchrotron x-ray studies, the team designed and employed an innovative 3-electrode cell for in situ measurements. This device let them alter the current and monitor phase transformations as the aqueous electrolyte solution flowed across the electrode containing FePO4 particles.
Their results allowed them to categorize the FePO4 particles into two groups. These groups are based on their distinctly paired phase evolutions upon lithiation (where a lithium atom replaces a hydrogen atom in an organic molecule) and sodiation (the replacement of metal ions [typically Li] with those of sodium) (Fig. 1), providing quantitative correlation maps based on Li preference, morphological features, and electrochemical properties. By selecting FePO4 particles with specific features, the results show the potential for fast Li extraction from a high-Li source, and high selectivity from a low-Li source in a single step.
See: Gangbin Yan1, ,Jialiang Wei2, Emory Apodaca1, Suin Choi1, Peter J. Eng1, Joanne E. Stubbs1, YuHan1, Siqi Zou1, Mrinal K. Bera1, Ronghui Wu1, Evguenia Karapetrova3, Hua Zhou3, Wei Chen2,4, and Chong Liu1*, “Identifying critical features of iron phosphate particle for lithium preference,” Nat. Commun. 15, 4859 (2024).
Author affiliations: 1The University of Chicago; 2Illinois Institute of Technology; 3Argonne National Laboratory; 4the University at Buffalo, The State University of New York
Correspondence: *chongliu@uchicago.edu
This work was supported by the University of Chicago Materials Research Science and Engineering Center, which is funded by the National Science Foundation under award number DMR-2011854. The x-ray diffraction and STEM characterizations received support from Department of Energy Office of Science (DE-SC0023317). This work made use of instruments in the Electron Microscopy Core, Research Resources Center in University of Illinois at Chicago. Portions of this work were performed at GeoSoilEnviroCARS , which is supported by the National Science Foundation-Earth Sciences (EAR-1634415). J.E.S and P.J.E. received further support from Department of Energy-Geosciences (DE-SC0019108). This research used resources of the Advanced Photon Source, a U.S. Department of Energy Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No.DE-AC02-06CH11357. NSF’s ChemMatCARS is supported by the Divisions of Chemistry and Materials Research, National Science Foundation, under grant number NSF/CHE-1834750.
For information on the Anomalous Small and Wide Angle X-ray Scattering (ASWAXS) program at NSF’s ChemMatCARS contact:
Mrinal Bera
(630) 252-0472
mrinalkb@uchicago.edu