Graphene quantum dots enable dendrite-free zinc ion battery

Abstract The practical application of aqueous Zn-ion batteries has been largely plagued by the poor reversibility of Zn anode, mainly associated with the dendritic growth and interfacial parasitic reaction. Hereby, electrochemically stable Zn anode is successfully designed by manipulating nucleation process through the introduction of hydrophilic graphene quantum dots (GQDs). Notably, the enhanced binding effect of GQDs with Zn2+ is aroused from the lower electronegativity of GQDs, which is conducive to accelerating uniform Zn deposition, resulting in the robust Zn anode without dendrites. Concomitantly, interfacial hydrogen bonds are excited by the GQDs with oxygen-containing groups, which is beneficial for mitigating water-induced side reaction and improving Zn ion reaction kinetics. Greatly, polarization voltage of symmetric cells is decreased from 80 to 50 mV at 0.8 mA cm-2, presenting a prolonged lifespan of 2200 h. As a result, the assembled ZIBs with vanadium cathode exhibit superior performance with capacity of 164.3 mAh g-1 after 600 cycles at 1 A g-1. Given this, this elaborate work might inaugurate a potential avenue for rationally tuning the electrode/electrolyte interface evolution towards advanced aqueous batteries.