Assessment of poly(vinylidene fluoride) copolymer blends as recent binders for lithium-ion batteries with LiMn2O4 cathode

Abstract

The binder composition of battery electrodes can be linked to their performance in different ways due to the remarkable impact of binder on the external properties of the battery. Even being electrochemically passive, the binding material in lithium-ion polymer battery electrodes significantly improves the operation metrics, including the cycle balance, capacity, and efficiency rate. This study compares the performance of LiMn2O4 cathode material, taking into consideration poly(vinylidene fluoride) (PVDF) binder mixed with other blended copoly­mers, such as polypropylene carbonate-poly(trimethylene carbonate) (PPC-PTMC) and polyethene-poly(ethylene oxide) (PE-PEO). As a mostly amorphous polymer, the PPC-PTMC copolymer is seen to have outstanding mechanical qualities that help to improve the adhesion and structural homogeneity of electrode material. Conversely, PE-PEO copolymer offers improved ionic conductivity within the electrode and binder when used as a polymeric surface-active agent for conductive additives. Compared to unblended PVDF binder, the improved structure homogeneity of the electrode results in remarkably better capacity, efficiency rate, and cycle performance. These results suggest that modifying the PVDF binder by copolymer combination is a workable way to enhance the homogeneity of electrode composites and interfaces.

Keywords

• Li-ion cell
• active materials
• electrode microstructure
• mechanical properties
• battery C rating