A novel polymer composite as cathode binder of lithium ion batteries with improved rate capability and cyclic stability

• Published in: Journal of power sources 2014-09, Vol.261, p.170-174
• Main Authors: Fu, Z., Feng, H.L., Xiang, X.D., Rao, M.M., Wu, W., Luo, J.C., Chen, T.T., Hu, Q.P., Feng, A.B., Li, W.S.
• Format: Article
• Language: English
• Subjects: Applied sciences; Binder; Binders; Cathode; Cathodes; Direct energy conversion and energy accumulation; Electric batteries; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrolytes; Exact sciences and technology; Lithium batteries; Lithium ion battery; Lithium-ion batteries; Maleic anhydride-grated-polyvinylidene fluoride; Materials; Polymer matrix composites; Polyvinylidene fluorides; Scanning electron microscopy
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2014.03.087

In this work, we have developed a novel polymer composite (MPVDF) by embedding maleic anhydride-grated-polyvinylidene fluoride (MA-g-PVDF) into polyvinylidene fluoride (PVDF) as binder of LiCoO2 cathode for lithium ion battery. The cathodes using MPVDF and PVDF as binder have been comparatively investigated with scanning electron microscope (SEM), X-ray diffraction (XRD) and electrochemical measurements. By using MPVDF as the binder for preparing LiCoO2 cathode, the rate capability and cyclic stability of the LiCoO2 cathode in LiCoO2/Artificial graphite battery are improved significantly. Compared to the cathode using PVDF alone, the discharge capacity of the battery increases by 38.5% at 2 C and the capacity retention of the battery is improved from 84.5% to 90.2% after 300 cycles at 0.5 C when the mass ratio of MA-g-PVDF to PVDF in MPVDF binder is 1:4. The improved performance is attributed to the low crystallinity of MPVDF, which allows larger electrolyte uptake. The electrolyte uptake is 43.5% for the LiCoO2 cathode using MPVDF but only 25.3% for the cathode using PVDF alone. •Composite of MA-g-PVDF with PVDF was developed as binder for LiCoO2 cathode of lithium ion battery.•Composite exhibits lower crystallinity than PVDF and increases electrolyte uptake of cathode.•Application of composite improves significantly rate capability and cyclic stability of battery.