Contact
    Start Publications One-step fabrication of robust lithium ion battery separators ...
    ←  Publication Finder
    Attension

    One-step fabrication of robust lithium ion battery separators by polymerization-induced phase separation

    Year: 2022

    Journal: J. Mater. Chem. A, Volume 10, MAY 17, page 10557–10568

    Authors: Manly, Alexander J.; Tenhaeff, Wyatt E.

    Organizations: National Science Foundation [1845805]; University of Rochester Materials Science Program; (DOE) CAMP (Cell Analysis, Modeling and Prototyping) Facility, Argonne National Laboratory; DOE Vehicle Technologies Office (VTO); Div Of Chem, Bioeng, Env, & Transp Sys; Directorate For Engineering [1845805] Funding Source: National Science Foundation

    Conventional lithium ion battery separators are microporous polyolefin membranes that play a passive role in the electrochemical cell. Next generation separators should offer significant performance enhancements, while being fabricated through facile, low cost approaches with the ability to readily tune physicochemical properties. This study presents a single-step manufacturing technique based on UV-initiated polymerization-induced phase separation (PIPS), wherein microporous separators are fabricated from multifunctional monomers and ethylene carbonate (EC), which functions as both the pore-forming agent (porogen) and electrolyte component in the electrochemical cell. By controlling the ratio of the 1,4-butanediol diacrylate (BDDA) monomer to ethylene carbonate, monolithic microporous membranes are readily prepared with 25 mu m thickness and pore sizes and porosities ranging from 6.8 to 22 nm and 15.4% to 38.5%, respectively. With 38.5% apparent porosity and an average pore size of 22 nm, the poly(1,4-butanediol diacrylate) (pBDDA) separator takes up 127% liquid electrolyte, resulting in an ionic conductivity of 1.98 mS cm(-1), which is greater than in conventional Celgard 2500. Lithium ion battery half cells consisting of LiNi0.5Mn0.3Co0.2O2 cathodes and pBDDA separators were shown to undergo reversible charge/discharge cycling with an average discharge capacity of 142 mA h g(-1) and a capacity retention of 98.4% over 100 cycles - comparable to cells using state-of-the-art separators. Moreover, similar discharge capacities were achieved in rate performance tests due to the high ionic conductivity and electrolyte uptake of the film. The pBDDA separators were shown to be thermally stable to 374 degrees C, lack low temperature thermal transitions that can compromise cell safety, and exhibit no thermal shrinkage up to 150 degrees C.
    View publication