Minimization of Ion–Solvent Clusters in Gel Electrolytes Containing Graphene Oxide Quantum Dots for Lithium‐Ion Batteries

Abstract This study uses graphene oxide quantum dots (GOQDs) to enhance the Li + ‐ion mobility of a gel polymer electrolyte (GPE) for lithium‐ion batteries (LIBs). The GPE comprises a framework of poly(acrylonitrile‐ co ‐vinylacetate) blended with poly(methyl methacrylate) and a salt LiPF 6 solvated in carbonate solvents. The GOQDs, which function as acceptors, are small (3−11 nm) and well dispersed in the polymer framework. The GOQDs suppress the formation of ion−solvent clusters and immobilize anions, affording the GPE a high ionic conductivity and a high Li + ‐ion transference number (0.77). When assembled into Li|electrolyte|LiFePO 4 batteries, the GPEs containing GOQDs preserve the battery capacity at high rates (up to 20 C) and exhibit 100% capacity retention after 500 charge−discharge cycles. Smaller GOQDs are more effective in GPE performance enhancement because of the higher dispersion of QDs. The minimization of both the ion−solvent clusters and degree of Li + ‐ion solvation in the GPEs with GOQDs results in even plating and stripping of the Li‐metal anode; therefore, Li dendrite formation is suppressed during battery operation. This study demonstrates a strategy of using small GOQDs with tunable properties to effectively modulate ion−solvent coordination in GPEs and thus improve the performance and lifespan of LIBs.