Ternary polymer electrolyte with enhanced ionic conductivity and thermo-mechanical properties for lithium-ion batteries

Cellulose is the main building block of plant's cell wall that provides structural stability. This idea inspired us to use modified cellulose (Networked cellulose) to provide thermal and mechanical stability to a polymer electrolyte system. The system composed of polyethylene glycol (PEG) (or tetraethylene glycol dimethyl ether (TEGDME)), polyethylene oxide (PEO), networked cellulose (NC) and LiClO₄ as a salt. The PEG (or TEGDME) was used as a high mobility phase for lithium ions, PEO acted as a binder and NC provided structural support for the quasi-solid polymer electrolytes. A high conductivity of the order of 10^-4 S cm^-1 was obtained at room temperature. Dynamic mechanical analysis of PEG (or TEGDME):PEO:NC (70:20:10 wt%) showed an improvement of storage modulus as compared to the pristine PEO in the 60-120 C temperature range. Differential scanning calorimetry (DSC)/Thermal gravimetry analysis (TGA) revealed that the developed ternary polymer electrolyte is thermally stable in the lithium-ion battery operational temperature range.