Atomic-Level Regulating Layer-by-Layer Zinc Deposition by High-Entropy Single-Atoms Electrolyte Additive

Aqueous batteries feature intrinsic safety, but how to achieve regular and planar electrodeposits at liquid-solid interfaces has emerged as a fundamental barrier to energy-dense aqueous batteries that use metal anodes. Based on classical crystal growth theory, sluggish metal ion transport during the deposition process will lead to rapid interfacial metal ion depletion, resulting in a sharp increase in interfacial supersaturation and subsequently inducing dendrite growth. Herein, micropore high-entropy single-atoms carbon nanoparticles (CuNiMnCoIr/CNs) were synthesized as a unique electrolyte additive to suppress interfacial Zn²⁺ concentration polarization and strengthen Zn chemistry at the atomic level. The micropore CuNiMnCoIr/CNs not only provide abundant Zn²⁺ transport channels but significantly reduce the migration energy barrier of Zn²⁺ from the bulk electrolyte to electrode interface to promote rapid desolvation kinetics and homogenize Zn²⁺ flux, thereby effectively alleviating interfacial Zn²⁺ supersaturation and guiding layer-by-layer Zn deposition. Consequently, trace CuNiMnCoIr/CNs additive delivers a high Zn²⁺ transference number of 0.89 and enables Zn//Zn cells to cycle stably for over 4000 h at 5 mA cm^-2, and 800 h even at 50 mA cm^-2, with an outstanding cumulative deposition capacity up to 20 Ah cm^-2. Such knowledge may provide new insights to challenge interface chemistry for advanced aqueous metal-ion batteries.