Fabrication of solid polymer electrolyte based on carboxymethyl cellulose complexed with lithium acetate salt as Lithium-ion battery separator

Polymer electrolyte is a crucial component of solid-state-lithium-ion batteries that role both as separators and electrolytes. The host polymer and lithium salt selection are crucial for producing a solid polymer electrolyte with optimum characteristics. This research aims to study the effect of lithium acetate (LiCH3COO) salt on carboxymethyl cellulose (CMC)-based solid polymer electrolytes. The LiCH3COO-complexed CMC solid polymer electrolyte was prepared using the solution casting method with various weight percentages of LiCH3COO, that is, 0%wt, 10%wt, 20%wt, and 30%wt. The ionic conductivity analysis was conducted by using electrochemical impedance spectroscopy (EIS), infrared analysis by Fourier transform infra-red (FTIR), mechanical analysis, crystallinity degree analysis with X-ray diffraction (XRD), and thermogravimetry analysis (TGA), differential thermogravimetry (DTG), and differential scanning calorimetry (DSC). The interaction between Li+ ions and CMC enhanced ionic conductivity, decreased mechanical strength, reduced crystallinity degree, and lowered thermal properties. The CMC/LiCH3COO (70/30) SPE was selected as the optimum condition because it exhibited good ionic conductivity and sufficient thermal stability, while it needs a mechanical strength improvement. Molecular dynamics simulations were also performed at the density-functional tight-binding (DFTB) level to unravel the molecular mechanism of the Li-ion hopping in CMC. The CMC/LiCH3COO (70/30) showed the highest electrochemical window as high as 3.5 V. Based on the results, CMC complexed with 30 (%wt) LiCH3COO salt showed high potential as a polymer electrolyte for lithium-ion battery applications.HighlightsFabrication of solid polymer electrolyte based on carboxymethyl cellulose complexed with lithium acetate salt was conducted by simple casting solution method.The 30%wt LiCH3COO into carboxymethyl cellulose (CMC)-polymer host showed the highest ionic conductivity of 2.47 x 10-5 S cm-1.The 30%wt LiCH3COO-complexed CMC shows some degradation peaks, they are water evaporation, decomplexation, depolymerization, melting, and completely degraded.The density-functional tight-binding method suggests that the Li-ions hop both in perpendicular and parallel directions of the cellulose layers.The CMC/LiCH3COO (70/30) showed the highest electrochemical window as high as 3.5 V. Fabrication SPE Based on CMC complexed with Lithium Acetate as Lithium-ion Battery Separator.image