Controlling the Potential of Affordable Quasi-Solid Composite Gel Polymer Electrolytes for High-Voltage Lithium-Ion Batteries

This study focuses on the development of a composite gel polymer electrolyte membrane (CGPEM) as a solution to address safety concerns arising from the reactivity of lithium metal and the formation of dendrites. The CGPEM integrates a solid polymer matrix, solid-electrolyte LSiPS (Li10SiP2S12), with a plasticizer that countering the performance decline caused by sulfide solid electrolyte (SSE) interactions with the cathode. Poly ethylene oxide (PEO) emerges as a promising polymer matrix due to its flexibility, cost-effectiveness, eco-friendliness, solvability for Li-salt, mechanical processing adaptability, adhesive strength, and ionic conductivity. Conductivity and processability of CGPEM were optimized through meticulous adjustment of liquid plasticizer concentration. The CGPEM ' s chemical and electrochemical stability were systematically investigated using in-situ electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRTs). A lithium metal battery is constructed against a high voltage cathode and newly developed CGPEM. Impressively, the cell exhibited outstanding performance, maintaining a discharge capacity of around 146.22 mAh/g after 200 cycles, retaining 86.38 % of its initial capacity. The formation of a LiF-rich interface layer near the lithium surface, a vital element in curbing CGPE degradation and dendritic growth, resulted in enhanced overall cell performance. A composite gel polymer electrolyte membrane (CGPEM), consisting of a solid polymer matrix, solid-electrolyte LSiPS (Li10SiP2S12), and a plasticizer, was prepared. The CGPEM showed good stability against Li metal by forming a LiF-rich compound at the Li interface. image