Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator.
Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO2) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB.
Carbon Composite Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeollabuk-do, 55324, Korea.
Sejoon
S
Park
Carbon Composite Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeollabuk-do, 55324, Korea.
Chung Woo
CW
Son
Carbon Composite Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeollabuk-do, 55324, Korea.
Sungho
S
Lee
Center for Materials Architecting, Korea Institute of Science and Technology, Hwarang-Ro 14gil-5, Seongbuk-Gu, Seoul 136-791, Republic of Korea.
Dong Young
DY
Kim
Department of Materials Science and Engineering, Yonsei University 50 Yonsei-Ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
Cheolmin
C
Park
School of Materials Science &Engineering (SMSE), Gwangju Institute of Science &Technology (GIST), Cheomdangwagiro 123 Gwangju, 61005, South Korea.
Kwang Sup
KS
Eom
School of Chemical &Bimolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Thomas F
TF
Fuller
Carbon Composite Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeollabuk-do, 55324, Korea.
Han-Ik
HI
Joh
Carbon Composite Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeollabuk-do, 55324, Korea.
Seong Mu
SM
Jo