Acrylonitrile-grafted poly(vinyl alcohol) copolymer as effective binder for high-voltage spinel positive electrode

• Published in: Journal of power sources Vol. 358; pp. 121 - 127
• Main Authors: Tanaka, Shinichi, Narutomi, Takuya, Suzuki, Shigeru, Nakao, Aiko, Oji, Hiroshi, Yabuuchi, Naoaki
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2017
• Subjects: Binder; Branched copolymer; Positive electrode; Spinel; Binder; Positive electrode; Spinel; Branched copolymer
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.05.032

Acrylonitrile-grafted poly(vinyl alcohol) copolymer with a branched structure is synthesized and used as binder for a LiNi1/2Mn3/2O4 composite electrode. Electrode performances of composite electrodes with different binders are compared in Li cells at 50 °C. The branched copolymer has better coatability to active materials in comparison to a simple mixture of linear polymers and conventional PVdF as evidenced by hard X-ray photoelectron spectroscopy. Cyclability is effectively improved by using the branched copolymer at elevated temperatures because of high chemical stability of the coated polymer layer and formation of a protective layer on cycles. Moreover, excellent rate-capability is realized by applying the branched copolymer with high adhesive strength, and the composite electrode delivers 70 mAh g−1 of discharge capacity at a rate of 1280 mA g−1. [Display omitted] •PAN-grafted PVA copolymer for the binder of LiNi1/2Mn3/2O4.•Highly improved electrode performance of LiNi1/2Mn3/2O4 at elevated temperatures.•The branched structure leading to good coatability with high adhesive strength.