From local solvation to bulk-electrolyte regulation: Coupling additive solvation and self-assembly for durable zinc-metal batteries

Current electrolyte-additive strategies in aqueous zinc-metal batteries (ZMBs) mainly optimize the local Zn 2+ solvation. Thus, simultaneously deactivating coordinated H 2 O, confining free H 2 O, and accelerating Zn 2+ reaction kinetics remains challenging because these effects are often coupled in a trade-off. To address this, we integrate individual-molecule solvation with additive self-assembly to extend regulation from local Zn 2+ solvation to the bulk electrolyte. As a proof-of-concept, amphiphilic organosilicon sulfonate 4,4-dimethyl-4-silapentane-1-sulfonate sodium salt (DSS) coordinates Zn 2+ through Zn 2+ –SO 3 2− and self-assembles into aggregates in the bulk electrolyte, where DSS coordination reconstructs Zn 2+ solvation, reducing and deactivating coordinated H 2 O, while its aggregates confine free H 2 O, limit the interfacial H 2 O accessibility, these finally suppressed hydrogen evolution. Meanwhile, the continuously distributed Zn 2+ -philic sites in DSS provide low-energy-barrier pathways for stepwise Zn 2+ migration, facilitating Zn 2+ flux and desolvation. Hence, this multilevel regulation simultaneously improves the H 2 O regulation and Zn 2+ reaction kinetics, overcoming their coupled trade-off. As a result, Zn||Zn symmetric cells cycle stably for over 3100 h at 1 mA cm −2 and 2 mAh cm −2 , and for over 700 h at 5 mA cm −2 and 10 mAh cm −2 . Zn||Cu asymmetric cells operate for more than 2000 cycles with an average Coulombic efficiency of 99.53%, while Zn||ZnVO full cells retain 90% of their initial capacity after 2000 cycles at 2 A g −1 . In short, this work identifies a new electrolyte-regulation mechanism in which individual-molecule solvation and additive self-assembly synergistically govern coordinated H 2 O, free H 2 O and Zn 2+ reaction kinetics, providing a new strategy for designing high-rate, long-life aqueous ZMB electrolytes.