Cellulose Acetate/PEG Nanocomposite Polymer Electrolytes with Improved Electrochemical Performance

Cellulose and its derivatives emerge as highly beneficial candidates for solid electrolytes. Their advantages include low‐cost production, no leakage, biodegradability, solid‐state stability, ease of processing, and good electrochemical stability. Although a strong ionic conductivity is essential for cellulose‐based solid electrolytes, the relatively low ionic conductivity of current cellulose‐based solid electrolytes remains a substantial challenge. This research seeks to address this critical gap with the development of a novel composite polymer electrolyte (CPE). Our approach utilizes a primary polymer matrix of cellulose acetate, which is supplemented by nanofillers, polyoxometalate (POM), along with LiPF 6 as the lithium salt and (polyethylene glycol) PEG as a plasticizer. The strategic incorporation of nanofillers is crucial as they enhance ionic conductivity and aid in the formation of pathways for ion movement within the electrolyte. The optimized CPE with a 5 wt.% nanofiller demonstrates an electrochemical stability window greater than 5 V, a lithium‐ion transference number of 0.58, and an impressive ionic conduction of 2.2 × 10 −4 S cm −1 at room temperature (RT). The prepared CPE indicated 86.03% Coulombic efficiency, the charge capacity value of 169.7 mAh/g, and capacity retention was more than 98% after 25 cycles at 0.5 C. Also, the electrolyte has good compatibility with lithium‐metal anodes, which allows the lithium symmetric cells to run steadily for over one hundred hours at 0.3 mA cm −2 current density.