Synergistic effect of dual additives enables dynamic regulation of zinc deposition for high-performance zinc-ion batteries

The dual-additive electrolyte additive strategies have emerged as a key method of mitigating the undesirable side reactions at the zinc anode in aqueous zinc-ion batteries (AZIBs) due to their simplicity and effectiveness. However, the daul-additive strategy is limited by its reliance on empirical selection, the lack of a universal design framework, and vulnerability to failure under harsh conditions. Herein, we propose an ethylene diamine tetraacetic acid (EDTA) modified coal-based carbon dots (CDs) multifunctional electrolyte additive that promotes homogeneous Zn deposition through the synergistic combination of an in-situ self-assembly carbon protective interphase and dynamic modulation of the hydrogen bond network. The carbon protective interphase can suppress side reactions between the Zn anode and active water species, while simultaneously enhance the interfacial Zn²⁺ flux kinetics. The dynamic presence of EDTA at the interface and in the bulk phase promotes Zn²⁺ migration through its strong chelating capability while also facilitating Zn²⁺ desolvation via the restructuring of the hydrogen bond network. Consequently, the reconstructed electrolyte system containing a multifunctional additive produces durable Zn anodes under high current density. The assembled Zn//Cu cells maintain a superior coulombic efficiency close to 100% for 2000 cycles at 10 mA cm⁻². The assembled Zn//Zn cells achieve steady charge–discharge for 11,700 cycles (1170 h) at 20 mA cm⁻². This work optimizes the solvation structure and interfacial coordination environment through a simple additive strategy, providing a potential strategy for developing advanced anode in ZIBs.