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

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 LiPF6 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 PF6− anions, affording the GPE a high ionic conductivity and a high Li+‐ion transference number (0.77). When assembled into Li|electrolyte|LiFePO4 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. A polymer framework decorated with graphene oxide quantum dots of gel polymer electrolytes minimizes the ion−solvent clusters that are present in liquid electrolytes for lithium‐ion batteries. The quantum dots function as acceptors to immobilize anions and lower the degree of Li+ solvation, substantially facilitating ion transport in the electrolyte bulk and transfer at the electrode–electrolyte interface.