Dual-function tetramethylammonium fluoride additive for high utilization aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have attracted extensive attention as promising candidates for next-generation grid-scale energy storage, benefiting from their intrinsic high safety, low cost, and competitive theoretical capacity. However, the rampant dendrite growth, severe hydrogen evolution reaction, and inevitable parasitic corrosion on zinc metal anodes, especially under high zinc utilization conditions, cause rapid interfacial degradation and premature cell failure, which severely restrict their practical commercialization. Herein, tetramethylammonium fluoride (NF) has been developed as a bifunctional electrolyte additive. Through the combination of cation electrostatic shielding and anion interface engineering, it inhibits dendrite growth and a series of adverse side reactions related to water, achieving a synergistic stabilizing effect on the zinc metal anode. Therefore, under the conditions of 20 µm thin zinc foil and 70% high zinc utilization rate, the Zn//Zn symmetric battery can achieve stable cycling for over 230 hours. Moreover, in the Zn//Cu battery, this highly reversible zinc plating/stripping process can be repeated for more than 1000 cycles, with an average coulombic efficiency of 99.64%. The full battery paired with a load of 11.94 mg per cm² KVO exhibits higher discharge specific capacity and cycle stability. After 1000 stable cycles at a current density of 1 A g⁻¹, the capacity shows no significant decline. Even at a high current density of 3 A g⁻¹, it still releases a specific capacity of approximately 145 mAh g⁻¹.