High-Yield Carbon Dots Interlayer for Ultra-Stable Zinc Batteries

Abstract

The practical implementation of Zn metal anodes with high volumetric capacity is seriously plagued by the dendritic growth and accompanying interfacial parasitic reactions. Herein, high yield carbon dots (CDs) with abundant polar functional groups (CHO and CN), as a functional artificial interface layer, are rationally designed to optimize electrolyte/Zn interfaces with large-scale viability. Of particular note, the quantum-sized CDs with strong Zn affinity can effectively ameliorate the electric field distribution and ensure that more Zn²⁺ is adsorbed onto the whole electrode, which are beneficial for lowering the barrier of Zn²⁺ nucleation and inducing homogeneous Zn deposition, thus rendering a dendrite-free Zn anode, as extensively confirmed by in situ optical microscope observation and finite element simulation. Meanwhile, the dense and insoluble coating layer with abundant polar functional groups is conducive to arousing the repulsion effect, which is good for shielding the active water and SO₄²⁻, thus eliminating the water-mediated parasitic reactions and improving Zn²⁺ reaction kinetics. More importantly, the electrochemically stable CDs layer endows the Zn anode with a prolonged lifespan of 3000 h at 1 mA cm⁻². This feasible and efficient fabrication of functional CDs layer opens a new avenue for stable dendrite-free metal anodes.