Selective Ion Transporting Polymerized Ionic Liquid Membrane Separator for Enhancing Cycle Stability and Durability in Secondary Zinc-Air Battery Systems.
Rechargeable secondary zinc-air batteries with superior cyclic stability were developed using commercial polypropylene (PP) membrane coated with polymerized ionic liquid as separators. The anionic exchange polymer was synthesized copolymerizing 1-[(4-ethenylphenyl)methyl]-3-butylimidazolium hydroxide (EBIH) and butyl methacrylate (BMA) monomers by free radical polymerization for both functionality and structural integrity. The ionic liquid induced copolymer was coated on a commercially available PP membrane (Celguard 5550). The coat allows anionic transfer through the separator and minimizes the migration of zincate ions to the cathode compartment, which reduces electrolyte conductivity and may deteriorate catalytic activity by the formation of zinc oxide on the surface of the catalyst layer. Energy dispersive X-ray spectroscopy (EDS) data revealed the copolymer-coated separator showed less zinc element in the cathode, indicating lower zinc crossover through the membrane. Ion coupled plasma optical emission spectroscopy (ICP-OES) analysis confirmed over 96% of zincate ion crossover was reduced. In our charge/discharge setup, the constructed cell with the ionic liquid induced copolymer casted separator exhibited drastically improved durability as the battery life increased more than 281% compared to the pure commercial PP membrane. Electrochemical impedance spectroscopy (EIS) during the cycle process elucidated the premature failure of cells due to the zinc crossover for the untreated cell and revealed a substantial importance must be placed in zincate control.
New Energy and Battery Engineering, Yonsei University , 134 Shinchon-dong, Seodaemoon-ku, Seoul 120-749, Republic of Korea.
Ho Jung
HJ
Hwang
Department of Chemical and Biomolecular Engineering, Yonsei University , 262 Seongsanno, Seodaemun-gu, Seoul 120-749, South Korea.
Won Seok
WS
Chi
Department of Chemical and Biomolecular Engineering, Yonsei University , 262 Seongsanno, Seodaemun-gu, Seoul 120-749, South Korea.
Ohchan
O
Kwon
Department of Chemical and Biomolecular Engineering, Yonsei University , 262 Seongsanno, Seodaemun-gu, Seoul 120-749, South Korea.
Jin Goo
JG
Lee
Department of Chemical and Biomolecular Engineering, Yonsei University , 262 Seongsanno, Seodaemun-gu, Seoul 120-749, South Korea.
Jong Hak
JH
Kim
New Energy and Battery Engineering, Yonsei University , 134 Shinchon-dong, Seodaemoon-ku, Seoul 120-749, Republic of Korea.|Department of Chemical and Biomolecular Engineering, Yonsei University , 262 Seongsanno, Seodaemun-gu, Seoul 120-749, South Korea.
Yong-Gun
YG
Shul
anion exchange membrane; durability; ionic liquid; separator; zinc−air battery