Graphene oxide quantum dots as an additive in the electrolyte for enhanced cycle retention of zinc-ion secondary battery

Abstract

The increasing global demand for renewable energy has intensified the need for efficient and stable energy storage systems capable of compensating for the intermittent nature of renewable power sources. Among various candidates, aqueous zinc-ion batteries have attracted significant attention as promising alternatives to conventional lithium-ion batteries, owing to their abundant zinc resources, high theoretical capacity, and excellent intrinsic safety derived from aqueous electrolytes. However, several technological limitations, such as zinc dendritic growth, hydrogen evolution reaction, corrosion, and byproduct formation, still hinder their practical application. Here, graphene oxide quantum dots (GOQDs) synthesized via pulsed laser ablation in liquid media are introduced as multifunctional electrolyte additives to stabilize the interface between Zn and electrolyte. The oxygen-rich GOQDs reconstruct the Zn2+ solvation shell and homogenize interfacial charge distribution, thereby suppressing dendrite formation and hydrogen evolution while accelerating Zn2+ transport. The Zn//Zn symmetric cell with GOQDs-added electrolyte exhibits an extended lifespan exceeding 150 h, which was approximately three times longer than that of the pristine electrolyte. Also, the Na2V6O16·2H2O//Zn full cell delivers 81.0 % capacity retention after 3000 cycles at 1 A g−1. This work establishes a laser-engineered nanocarbon strategy that enables controlled interfacial chemistry and facet-selective stabilization, providing molecular-level insight into electrolyte design principles for achieving dendrite-free, durable, and intrinsically safe batteries.