Competitive solvation with regulated ion-coordination chemistry toward dendrite-free and long-life Zn metal anodes

Aqueous zinc-ion batteries (AZIBs) are emerging as a promising energy storage system due to their low cost and high safety. However, several challenges such as side reactions and uneven Zn deposition limit their broader application. Herein, we introduce potassium sorbate (Ps) as a multifunctional trace additive to enhance the performance of AZIBs. Experimental characterization and theoretical analysis reveal that the sorbate anions (Ps−) ionized by Ps restructure the solvation of Zn2+ ion through strong Zn2+-Ps− coordination and further adsorb onto the Zn anode, forming an anode-molecule interface. Consequently, this leads to amplified spatial steric hindrance effect, occupation of active sites, and a reduction in the number of coordinated H2O, thereby inducing homogeneous Zn2+ ion deposition and inhibiting undesirable side reactions. Noticeably, with the addition of Ps−, the symmetric cell achieves an ultra-long lifespan of nearly 5000 hours at 1 mA cm−2 and 1 mA h cm−2, and the Zn||Cu asymmetric cell delivers an average coulombic efficiency of 99.72% after 2000 cycles. Furthermore, Zn//V2O5 full cell retains a capacity retention rate of 79% after 3000 cycles at 3A g−1.