PUBLICATION

Advanced Soft Energy Materials Lab

Publication

Publication

3. Significance of ferroelectric polarization in poly (vinylidene difluoride) binder for high-rate Li-ion diffusion
Authors
Woo-Jin Song, Se Hun Joo, Do Hyeong Kim, Chihyun Hwang, Gwan Yeong Jung, Sohyeon Bae, Yeonguk Son, Jaephil Cho, Hyun-Kon Song, Sang Kyu Kwak*, Soojin Park*, SeokJu Kang*
Journal
Nano Energy
Vol
32()
Page
255-262
Date
(2017.02), JCR: 2.29%
Year
2017
An interesting and effective route for improving battery performance using ferroelectric poly(vinylidene difluoride) (PVDF) polymer as a binder material is demonstrated in this work. A ferroelectric PVDF phase developed under the appropriate thermal annealing process enables generation of suitable polarization on active materials during the discharge and charge process, giving rise to longer capacity with lower overpotential at a high current rate. Electrochemical analysis including in situ galvanostatic electrochemical impedance spectroscopy and a galvanostatic intermittent titration measurement revealed that the ferroelectric binder effectively reduced Li-ion diffusion resistance and supported fast migration in the vicinity of active electrodes. Computational results further support that the binding affinity of the ferroelectric PVDF surface is much higher than that of the paraelectric PVDF, confirmed by ideally formed ferroelectric and paraelectric PVDF conformations with Li-ions. Furthermore, we consistently achieved high Li-ion battery (LIB) performance in full cell architecture consisting of a LTO/separator/LFP with a ferroelectric PVDF binder in the anode and cathode materials, revealing that the polarization field is important for fabricating high-performance LIBs, potentially opening a new design concept for binder materials.