Oligoether/Zwitterion Diblock Copolymers: Synthesis and Application as Cathode-Coating Material for Li Batteries
Department of Materials and Life Sciences, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
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Academic Editor: Antonino S. Aricò
Polymers 2021, 13(5), 800; https://doi.org/10.3390/polym13050800
Received: 19 February 2021
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Revised: 1 March 2021
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Accepted: 2 March 2021
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Published: 5 March 2021
(This article belongs to the Special Issue Advanced Functional Polymers for Energy Applications)
Poly (ethylene oxide) (PEO) has been investigated as an ion-conductive matrix for several decades due to its excellent properties. However, further improvements are needed to enable a PEO-based ion-conductive matrix for practical applications. In order to develop novel solid polymer electrolytes based on zwitterions, we synthesized diblock copolymers (PPEGMA-b-SPBs) with oligoether and zwitterionic side-chains and evaluated their physico-chemical properties. PPEGMA-b-SPBs with various unit ratios were synthesized by RAFT polymerization. PPEGMA-b-SPBs with/without LiTFSA exhibited two distinct glass transition temperatures regardless of the unit ratio of PEGMA and SPB. AFM observations clearly revealed phase-separated structures. The ionic conductivity of PPEGMA-b-SPBs increased even at a high salt concentrations such as [EO]:[Li] = 6:1 and was over 10−5 S cm−1 at 25 °C. This tendency is unusual in a PEO matrix. The oxidation stability of PPEGMA-b-SPBs was about 5.0 V vs. Li/Li+, which is a higher value than that of PEO. The improvement of the electrochemical properties is attributed to the introduction of the SPB block into the block copolymers. PPEGMA-b-SPBs were evaluated as cathode-coating materials for Li batteries. The discharge capacity and coulombic efficiency of the cells employing the cathode (LiNi1/3Mn1/3Co1/3O2 (NMC)) coated with the block copolymers were much higher than those of the cell employing the pristine cathode at the 50th cycle in the cut-off voltage range of 3.0–4.6 V.
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MDPI and ACS Style
Yoshizawa-Fujita, M.; Ishii, J.; Takeoka, Y.; Rikukawa, M. Oligoether/Zwitterion Diblock Copolymers: Synthesis and Application as Cathode-Coating Material for Li Batteries. Polymers 2021, 13, 800. https://doi.org/10.3390/polym13050800
AMA Style
Yoshizawa-Fujita M, Ishii J, Takeoka Y, Rikukawa M. Oligoether/Zwitterion Diblock Copolymers: Synthesis and Application as Cathode-Coating Material for Li Batteries. Polymers. 2021; 13(5):800. https://doi.org/10.3390/polym13050800
Chicago/Turabian StyleYoshizawa-Fujita, Masahiro, Jun Ishii, Yuko Takeoka, and Masahiro Rikukawa. 2021. "Oligoether/Zwitterion Diblock Copolymers: Synthesis and Application as Cathode-Coating Material for Li Batteries" Polymers 13, no. 5: 800. https://doi.org/10.3390/polym13050800
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