Solid state electrolytes are of great importance in electrochemical devices such as lithium ion batteries and dye sensitized solar cells as they are safer and eliminate the need for extensive sealing issues. Polyethylene oxide (PEO) is a known solid electrolyte for Li ion batteries; however, its mechanical strength starts deteriorating at higher temperatures. In this work we have used electrospinning technique to form PEO nano-fiber mats with a novel cellulosic reinforcement material named GELPEO. The reinforced fiber mats show a two-fold increase in the tensile strength and up to five times increase in the Young's modulus. Thermal behavior studies revealed that the electrolyte is stable at temperatures above 200 °C and thus can be safely used in Li batteries. Scanning electron microscope (SEM) images showed formation of thinner fibers with the addition of GELPEO in PEO. Ionic conductivity of the order of 10−4 S/cm is achieved for both PEO and PEO/GELPEO samples at 100 °C.