Viscosity of Suspensions of Strongly Bonded Spherical Particles of Nickel-Manganese-Cobalt Mixed Oxides (NMC) in Molten Poly(Ethylene Carbonate) for Batteries.

Abstract

Ionically conductive polymers highly filled with active materials, such as metal oxides are increasingly studied for their potential use in all solid-state batteries. They offer the desirable processing ease of polymers for mass production despite interfacial issues that remain to be solved. In this study, it is shown that spherical particles of transition metal oxides can be introduced in co-polymers of alkene carbonate and ethylene oxide at loading close to the maximum packing fraction, without imparting the processability in the melt of the material. In particular, the viscosity does not show any yield stress and the increase of viscosity shows that the intrinsic viscosity of the filler does not match with the usual 2.5 value in the limit of the Einstein's equation. Conversely, rheological data show that the value is rather close to unity consistently with theoretical arguments that predicted that this scaling factor should be unity when particle rotation is precluded. In the present case, this behavior is attributed to strong bonding between polymer and filler that is proved by electronic microscopy and by dynamical mechanical spectroscopy showing a relaxation due to bound polymer.