Optimization of LiFePO₄ Nanoparticle Suspensions with Polyethyleneimine for Aqueous Processing

Journal Article · Tue Jan 31 00:00:00 EST 2012 · Langmuir

DOI:https://doi.org/10.1021/la205157d· OSTI ID:1037632

Li, Jianlin ^[1]; Armstrong, Beth L. ^[1]; Kiggans, Jim ^[1]; Daniel, Claus ^[2]; Wood, David L. ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division; Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary Research and Education

Addition of dispersants to aqueous based lithium-ion battery electrode formulations containing LiFePO₄ is critical to obtaining a stable suspension. The resulting colloidal suspensions enable dramatically improved coating deposition when processing electrodes. This research examines the colloidal chemistry modifications based on polyethyleneimine (PEI) addition and dispersion characterization required to produce high quality electrode formulations and coatings for LiFePO₄ active cathode material. The isoelectric point, a key parameter in characterizing colloidal dispersion stability, of LiFePO₄ and super P C45 were determined to be pH = 4.3 and 3.4, respectively. PEI, a cationic surfactant, was found to be an effective dispersant. It is demonstrated that 1.0 wt % and 0.5 wt % PEI were required to stabilize the LiFePO₄ and super P C45 suspension, respectively. LiFePO₄ cathode suspensions with 1.5 wt % PEI demonstrated the best dispersibility of all components, as evidenced by viscosity and agglomerate size of the suspensions and elemental distribution within dry cathodes. In conclusion, the addition of PEI significantly improved the LiFePO₄ performance.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: Work for Others (WFO); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1037632
• Journal Information: Langmuir, Vol. 28, Issue 8; ISSN 0743-7463
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Zeta potential
isoelectric point
LiFePO4
polyethyleneimine
dispersant
Materials processing
lithium-ion batteries