Aromatic additives with designed functions ameliorating chemo-mechanical reliability for zinc-ion batteries

Zn-ion batteries (ZIBs) emerge as potential candidates for scalable energy storage due to their advantages of high safety and excellent performance. However, the implementation of zinc-metal anode faces challenges, such as dendrite growth, hydrogen evolution, and by-product formation. Herein, we explore an archive of aromatic molecules with different ligands, encompassing carboxyl, hydroxyl, aldehyde, and sulfonate groups as electrolyte additives. Testing results provided an insight into the molecular structure, charge state, and chelating groups on the chemo-mechanical stability of ZIBs. The calculation results reveal that carboxyl and hydroxyl ligands allow stronger chemisorption on metallic Zn. Chelating properties of salicylate and catecholate ligands facilitate efficient solvation based on additive-Zn2+ coordination. The aldehyde and sulfonate ligands promote a textural growth of the (002) plane attributed to their lipophilic properties. The sulfonate-based molecules offer collective benefits owing to their large polar surface and designed textural deposits. The deposition of additive-Zn2+ complexes yields a robust layer with concentration gradients, thus hindering the crack propagation induced by oxidative stress. Zn//Zn stability tests show that sulfonate additives improved a lifetime from 50 to 3000 cycles at 2 mA cm−2 and 1 mAh cm−2. The results open a new strategy to develop and optimize advanced electrolytes for aqueous energy storage.