Networked cellulose entrapped and reinforced PEO-based solid polymer electrolyte for moderate temperature applications

A novel solid polymer electrolyte (SPE) composed of poly (ethylene oxide) (PEO) and networked cellulose (NC) is developed for moderate temperature applications typically 50 to 100°C. The SPE thus formed demonstrates enhanced strength; high thermal and appropriate electrochemical stability. NC is a high strength polymeric material with a network structure possessing open spaces in its construction. The NC open spaces shrink on drying. The SPEs are formed by solution casting different amounts of NC in dissolved PEO. NC was formed by the acid hydrolysis and regeneration of microcrystalline cellulose (MCC). SEM, TEM and in-situ optical images revealed that the dissolved PEO solidified around the suspended NC and the open structure of NC entraps PEO upon drying. NC provides structural and thermal stability to the SPE. With an addition of 15wt% NC in SPE there was about five-time increase in both tensile as well as storage modulus measured via tensile testing and Dynamic mechanical analysis (DMA) respectively. The enhancement of mechanical strength is explained using the Zener model. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) studies validated that the electrochemical stability window of PEO+15 wt %NC with salt and that of neat PEO with salt are analogous.