Ultra-Trace Electrolyte Additives for Ah-Level Zinc-Ion Batteries Through Lattice-Matching Strategy.

Aqueous zinc ion batteries (AZIBs) represent a highly promising technology; however, practical deployment remains impeded by uncontrolled dendritic growth and side reactions. To address these fundamental limitations, the rational design and synthesis of a novel electrolyte additive is reported here, guided by the lattice matching principle, in which thioctic acid (TA) is covalently grafted onto an Anderson-type polyoxometalate (POM). During electrochemical operation, TA moieties selectively adsorb onto the Zn anode surface and undergo in situ electrochemical polymerization. Due to the Zn-S interaction, Zn2+ preferentially bind to the sulfur rich polymer chains with a periodic distance of 4.62 Å for S···S, which is perfect in agreement with the distance of zinc atoms (4.55 Å) along [1 1 ¯ 0] direction within (002) crystal plane, thereby inducing the atomic level deposition of Zn2+. The Zn||I2 cell exhibits outstanding longevity, retaining stable performance for more than 20 000 cycles at 10 A g-1. Furthermore, a pouch battery with 1.6 Ah capacity retains over 99% of its initial capacity after 325 cycles. Remarkably, even at an ultralow concentration of 0.001%, the prepared electrolyte additive can enhance cycling stability. Through this work, an ultra-trace additive-enabled, atomic-scale interfacial engineering paradigm for AZIBs is established.